blanco et al 2013 b epitope multiplicity and b/t epitope orientation influence immunogenicity of...

Hindawi Publishing CorporationClinical and Developmental ImmunologyVolume 2013 Article ID 475960 9 pageshttpdxdoiorg1011552013475960

Research ArticleB Epitope Multiplicity and BT Epitope Orientation InfluenceImmunogenicity of Foot-and-Mouth Disease Peptide Vaccines

Esther Blanco1 Carolina Cubillos1 Noelia Moreno1 Juan Baacutercena1 Beatriz G de la Torre2

David Andreu2 and Francisco Sobrino13

1 Centro de Investigacion en Sanidad Animal (CISA-INIA) Valdeolmos 28130 Madrid Spain2Departament de Ciencies Experimentals i de la Salut Universitat Pompeu Fabra 08003 Barcelona Spain3 Centro de Biologıa Molecular ldquoSevero Ochoardquo (CSIC-UAM) Cantoblanco 28049 Madrid Spain

Correspondence should be addressed to Francisco Sobrino fsobrinocbmuames

Received 12 August 2013 Accepted 31 October 2013

Academic Editor Pedro A Reche

Copyright copy 2013 Esther Blanco et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Synthetic peptides incorporating protective B- and T-cell epitopes are candidates for new safer foot-and-mouth disease (FMD)vaccines We have reported that dendrimeric peptides including four copies of a B-cell epitope (VP1 136 to 154) linked to a T-cellepitope (3A 21 to 35) of FMD virus (FMDV) elicit potent B- and T-cell specific responses and confer protection to viral challengewhile juxtaposition of these epitopes in a linear peptide induces less efficient responses To assess the relevance of B-cell epitopemultivalency dendrimers bearing two (B

2T) or four (B

4T) copies of the B-cell epitope from typeO FMDV (awidespread circulating

serotype) were tested in CD1 mice and showed that multivalency is advantageous over simple B-T-epitope juxtaposition resultingin efficient induction of neutralizing antibodies and optimal release of IFN120574 Interestingly the bivalent B

2T construction elicited

similar or even better B- and T-cell specific responses than tetravalent B4T In addition the presence of the T-cell epitope and its

orientation were shown to be critical for the immunogenicity of the linear juxtaposed monovalent peptides analyzed in parallelTaken together our results provide useful insights for a more accurate design of FMD subunit vaccines

1 Introduction

Foot-and-mouth disease (FMD) is a highly infectious diseaseof cloven-hoofed animals admittedly the most importantlivestock disease in terms of economic impact [1 2] In manyareas of the world (Africa Asia and to some extent SouthAmerica)where it remains endemic FMDseverely handicapsaccess to international meat markets [3] FMD control inendemic regions is implemented mainly by using chemicallyinactivated whole-virus vaccines whose production (large-scale growth of virulent FMD virus (FMDV) virus inactiva-tion antigen concentration and purification) has remainedlargely the same for decades [4 5] This practice posesserious biosafety concerns as the risk of virus release duringvaccine production is well documented [4 6] Additionalshortcomings of current FMD vaccines include the need fora cold chain to preserve virus stability and the difficultyof serological distinction between infected and vaccinated

animals [4] These concerns along with the severe traderestrictions applied in any vaccination campaign have ledFMDV-free countries to adopt nonvaccination policies inthe event of an FMD outbreak Such policies have involvedmassive slaughtering of infected or suspected (contact) herdsas well as strict limitations on farm animal movements all ofwhich have raised significant controversies [7 8]

In this context peptide-based approaches appear to bean attractive strategy for FMD vaccine development Peptidevaccines offer several advantages over other types of vaccinessuch as (i) lack of infectious agent which ensures absolutesafety (ii) accurate molecular delineation of the immunogenwhich allows to exclude detrimental sequences present infull-length antigens or other pathogen-relatedmolecules andpermits easy differentiation of infected from vaccinated ani-mals (referred as DIVA vaccines) (iii) easy access and scaleup by peptide synthesis methods and (iv) uncomplicatedtransport and storage [9 10] However despite their promises

2 Clinical and Developmental Immunology

candidates for next-generation vaccines and peptides aretypically poorly immunogenic

In the case of FMD the main antigenic sites recognizedby B lymphocytes have been identified at defined structuralmotifs exposed on the surface of the FMDV capsid whoseamino acid sequences accumulate variations among differentserotypes [11 12] A continuous immunodominant B-cellsite located in the GH loop around positions 140 to 160 ofcapsid protein VP1 has been widely used as an immunogenicpeptide [13] However the protection against FMD conferredto natural hosts by linear peptides spanning the GH loopof VP1 is limited [13 14] Although it is generally acceptedthat protective immunity to FMDV is mostly due to neu-tralizing antibodies a T-cell response is also necessary foreffective immunity [15] We have reported that inclusion ofa specific T-cell epitope located in residues 21 to 35 of FMDVNS protein 3A [16] juxtaposed in a linear fashion to theabove-mentioned B-cell epitope affords significant reductionin virus excretion and clinical scores after challenge [17]This monomeric peptide B-T however did not afford fullprotection in challenged pigs

In order to enhance the effectiveness of presentation ofthe above B- and T-cell epitopes to the immune systema multimerization approach consisting of a dendrimericpeptide bearing four copies of the B-cell epitope and oneof the Th epitope was explored The branched constructgenerically known as B

4T elicited high titers of FMDV-

neutralizing and IgA antibodies in both pig and outbredmice (CD1 strain) activated T-cells and induced IFN120574 releaseThe dendrimer performed as an effective peptide vaccineconferring solid protection in swine against type C FMDVchallenge [18]

With a view to extending these proof-of-conceptresults to epidemiologically relevant FMDV serotypes wehave designed and produced new B

4T constructs harbor-

ing sequences from type O FMDV (currently the mostwidespread serotype) [3 19] as B-cell epitopes To assess therelevance of B-cell epitope multivalency constructs bearingtwo (B

2T) or four (B

4T) copies of the B-cell epitope were

tested in CD1 mice showing that multivalency is advant-ageous over simple B-T-epitope juxtaposition but also thatbivalent B

2T constructions elicit similar or even better

humoral and cellular specific responses than tetravalent ones[20] Herein we show that epitope density is essential forinducing an efficient humoral immune response includingneutralizing antibodies but also for optimal release ofIFN120574 a relevant antiviral cytokine In addition we evaluatethe orientation of T-relative to B-cell epitopes in juxta-posed monovalent constructs in terms of efficient T-Bcell cooperation and induction of cellular response Takentogether our results provide useful insights for a more accu-rate design of subunit vaccines

2 Materials and Methods

21 Peptides Peptides reproducing the B [VP1(136ndash150)] andT [3A(21ndash35)] epitopes of type O FMDV (O-UKG 1101) indifferent arrangements are shown in Table 1 Linear B T BTand TB peptides were made by Fmoc solid phase synthesis as

previously described [17] Bi- and tetravalent constructs B2T

and B4Tweremade by thioether ligation protocols as detailed

in Monso et al [20] and Cubillos et al [18] respectively Allsix peptides were purified by reverse phase HPLC to gt95purity and satisfactorily characterized by MALDI-TOF massspectrometry

22 Virus A virus stock derived from serotype O-UKG 1101(supplied by The Pirbright Institute UK) by two amplifi-cations in IBRS-2 cells which maintained the consensussequences at the capsid protein region was used in this study

23 Mice and Immunization The immune response inducedby the various peptide constructions on Table 1 was assessedin outbred Swiss mice (Swiss ICR-CD1 Harlan Laboratories)5- to 6-week-old female mice in groups of 6 to 9 were main-tained under standard housing conditions in the CBMSOAnimal Care unit Mice were immunized subcutaneouslyat days 0 and 18 with 100 120583g of each peptide emulsified inMontanide ISA 50V2 (Seppic France) and sacrificed at day39 Two groups of 4 mice each were immunized as controlswith either adjuvant or PBS Blood samples were collected bytail bleeding before priming (day 0) and at days 14 20 and39 (sacrifice) All experimental procedures were conductedin accordancewith protocols approved by theCBMSO ethicalcommittee

24 Virus Neutralization Test (VNT) Virus neutralizationactivity was determined in sera by a standard microneutral-ization test performed in 96-well plates by incubating serialtwofold dilutions of each serum sample with 100 50 tissueculture infective dose (TCID50) of FMDVO-UK01 for 1 h at37∘CThe remaining viral activity was determined in 96-wellplates containing freshmonolayers of BHK-21 cells Endpointtiters were calculated as the reciprocal of the final serumdilution that neutralized 100 TCID50 of FMDV (O-UK01)in 50 of the wells [22]

25 Detection of Specific Anti-FMDV Antibodies By ELISATotal antibodies against FMDV were examined by ELISAin serum samples collected at day 39 Briefly Maxisorp 96-well plates (Nunc) were coatedwith sucrose gradient-purified140rsquos FMDV O UKG 112001 particles in PBS overnight at4∘C (01120583gwell) Then wells were washed with PBS andblocked with 5 skimmed milk in PBS for 2 h at 37∘CDuplicate threefold dilution series of each serum sample wereprepared starting at 1100 and made up at 50 120583L Preim-mune sera from peptide-immunized mice and sera fromnonimmunized animals were used as negative controls Spe-cific antibodies were detected with horse radish peroxidase-(HRP-) conjugated goat anti-mouse IgG (Zymed Invitro-gen) diluted 13000 Colour development was obtained afteraddition of 100 120583Lwell of the soluble substrate 331015840551015840-tetramethylbenzidine (TMB Sigma) and stopped by an equalvolume of 1M H

2SO4 Plates were read in a Fluostar Omega

microplate reader at 450 nm In this assay it was found thatthe point on the titration curve corresponding to an A

450of

10 invariably fell on the linear part of the curve Antibodytiters were therefore expressed as the reciprocal of the last

Clinical and Developmental Immunology 3

Table 1

Peptidename FMDV protein (residues) Structurelowast

B VP1 (136ndash154) PVTNVRGDLQVLAQKAART

T 3A (21ndash35) AAIEFFEGMVHDSIK

BT VP1 (136ndash154)-3A (21ndash35) PVTNVRGDLQVLAQKAARTAAIEFFEGMVHDSIK

TB 3A (21ndash35)-VP1 (136ndash154) AAIEFFEGMVHDSIKPVTNVRGDLQVLAQKAART

B2T [VP1 (136ndash154)]2-3A (21ndash35)

Ac-PVTNVRGDLQVLAQKAARTC


O

O

KKndashKAAIEFFEGMVHDSIK






O

O

O

O

K

K


lowastAll peptides in C-terminal carboxamide form The arrow in B2T and B4T structures indicates a putative cathepsinD cleavage site [21]

dilution calculated by interpolation to give an absorbance of1 above background

26 Detection of Isotype-Specific Anti-FMDV Antibodies byELISA FMDV-specific IgG1 IgG2a IgG2b (in sera) and IgA(in sera and nasal swabs) weremeasured using amodificationof the ELISA described above 100 120583L volumes were usedthroughout In the case of nasal swabs two consecutiveincubations with sample were performed before adding thecommercial antibody (Sigma) to mouse IgA in order toincrease the sensitivity of the assay Isotyping ELISA was per-formed using a goat anti-mouse specific for mouse isotypesand as secondary a rabbit anti-goatHRP-IgG (both by Sigma)Plates were developed by TMB before the stop solution(016M H

2SO4) was added and read at 450 nm as above

Endpoint titers were expressed as the reciprocal log10

ofserumdilutions giving the absorbance recorded in the controlwells (serum collected day 0) plus twice standard deviationThese data were calculated by interpolation IgA titers innasal swabs were expressed as the absorbance at a dilution of1 10

27 IFN-120574 Detection by ELISPOT A mouse IFN-120574 ELISPOTreagent kit was used according tomanufacturerrsquos instructions(BD Biosciences) Briefly after red blood cell lysis (1 and8 times 105) splenocytes were distributed in triplicate wells of

Immobilon-P hydrophobic PVDF 96-well plates (Millipore)previously coated with an anti-mouse IFN-120574 antibody andthen blocked with RPMI 1640 (Gibco) supplemented withglutamine penicillinstreptomycin and 10 inactivated FSBCells were stimulated with either autologous peptide at aconcentration of 04120583gwell or with 1120583gwell of sucrosegradient-purified FMDV (O UKG 112001) Triplicate wellswith 8 times 105 cells without peptide were used to estimatenonspecific activation As positive control triplicate wellswith 8 times 105 cells were stimulated with phytohemagglutinin(Sigma) at 10120583gmL per well After 48 h at 37∘C 5 CO

2and

95 relative humidity plateswerewashed and incubatedwitha biotinylated anti-mouse IFN-120574 antibody followed by HRP-streptavidin Antibody binding was visualized by the sub-strate 3-amino-9-ethylcarbazole The frequency of peptide-and virus-specific T cells present in the responding popula-tion was expressed as the mean number of spot-forming cells(SFC) counted in stimulated wells per 106 splenocytes

28 Statistical Analyses Statistical significance between threeand more groups was calculated with one-way ANOVAfollowed up by multiple comparison post-tests (Bonferronior Tukey test depending on the sample sizes compared) Sta-tistical tests were performed using Prims software (GraphPadSoftware) 119875 values are depicted as follows lowast119875 lt 005 lowastlowast119875 lt001 and lowastlowastlowast119875 lt 0001


0 14 20 390

1

2

3

4

5

TBB

BT

Days postimmunization

B4TB2T

FMD

V an

tibod

y tit

ers (

log1

0)

Figure 1 Time course study of antibody responses to FMDV in seraanalyzed by ELISA Specific antibody titers against FMDV (O UKG112001) measured by ELISA in serum samples collected at days 014 20 and 39 postimmunization Antibody titers were expressed asthe reciprocal log

10of the last dilution calculated by interpolation to

give an absorbance of 1 above background Each point correspondsto the geometric mean of a least two determinations In all cases thestandard deviation was lt10 Arrows indicate immunization (firstdose and boost) dates

3 Results

31 B and T Epitope Relative Positioning and B Epitope Multi-plicity Are Both Essential for Anamnestic Humoral Responsesagainst FMDV Various presentations of the FMDV B andT epitopes (Table 1) were used to address issues such as (i)the effect of a T epitope on immunogenicity or the idealrelative orientation of juxtaposed B and T epitopes displayedin linear peptides and (ii) how B epitope multiplicity bore onthe immune response of branched constructs B

2T and B

4T

In contrast to B cell epitopes for which multiple presentationhas a favourable effect on the immune response (see below)T-cell stimulation and the ensuing enhancement in immuneresponse are achievable by a single copy of the epitopeUpon this rationale T

2B and T

4B architectures though

synthetically feasible were predicted as unpromising hencedisregarded for this study

Specific anti-FMDV antibodies were determined byELISA in the sera of peptide-immunized mice collected atdays 0 14 20 and 39 As expected no anti-FMDV antibodieswere detected in animals inoculated with peptide T (data notshown) On the contrary all peptides in Table 1 containingthe B cell epitope elicited significant (gt 1log

10) anti-FMDV

titers after a single dose (Figure 1) However clear differencesamong the peptides were recorded in the humoral responseinduced by the booster injection Thus only the branchedB4T and B

2T constructs and monomeric BT with the B at

the N-terminus and followed by the T-cell epitope sequence

BT TB B0

1

2

3

Peptides

lowastlowastlowast lowastlowastlowast

B4T B2T

VN

T (lo

g10

)

Figure 2 Antibody responses to FMDV in sera analyzed byneutralization assay at day 39 postimmunization The VNT titersdetermined in each group of mice were expressed as the reciprocal(log10) of the last dilution able to neutralize 100 TICD

50of homolo-

gous virus Animals with VNT ge 1 are considered seropositive Eachsymbol represents the value for an individual animal Horizontallines indicate the mean value for each group of animals Statisticaldifferences between B

2T group and the others are indicated by 119875

values

were able to induce secondary antibody responses after re-exposure to immunogenThis suggests that placing the B-cellepitope at the N-terminal to the T-cell epitope is essential foreffective cooperation particularly for specific B-cell memoryinduction

Regarding the magnitude of humoral response the titreof specific antibodies against FMDV was highest in miceimmunized with dendrimeric B

2T (average titer 42plusmn06 SD)

well above (about 1 log) those of tetravalent B4T and linear

BT both of which induced similar responses

32 Multiple Presentation of B-Cell Epitopes in DendrimericConstructions Significantly Enhances the Generation of SpecificVirus Neutralizing Antibodies Clear and significant differ-ences in the virus neutralizing antibody titers (VNT) werefound after immunization with either dendrimeric or linearpeptides The highest VNT was detected in mice immunisedwith bivalent B

2T (Figure 2) All the animals within this

group (119899 = 9) had significant VNT (gt 1 log) The magnitudeof neutralizing antibody response in B

2T group was even

significantly higher than that induced by the other den-drimeric peptide assayed the B

4T construction (119875 lt 0001)

These statistical differences in the neutralizing antibody titersinduced by the peptide B

2T were also found relative to the

monomeric constructions (BT TB and B) (Figure 2)Regarding VNT induced by the monomeric peptides

(BT TB and B) they were only detectable in the first (BT-immunized) group albeit below the significance threshold(3 out of 6 immunized mice) These results suggest thatmultimeric presentation of B-cell epitopes in the dendrimersas well as the presence of a T-cell epitope in an adequateorientation in linear peptides enhance the induction of VNantibodies Again no anti-FMDV neutralizing antibodies


BT TB B0

2

4

6

Peptides

lowast

lowastlowast

lowastlowast

lowastlowast

IgG1

titer

s (lo

g10

)

B4T B2T

(a)

BT TB B0

2

4

6

Peptides

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

IgG2

a tite

rs (l

og10

)

B4T B2T

(b)

BT TB B0

2

4

6

Peptides

lowastlowastlowastlowast

IgG2

b tit

ers (

log1

0)

B4T B2T

(c)

Figure 3 Isotype-specific antibody (IgG1 and IgG2aG2b) responses to FMDV in sera analyzed by ELISA at day 39 postimmunizationEndpoint titers were expressed as the reciprocal log

10of serum dilutions giving the absorbance recorded in the control wells (serum collected

day 0) plus twice standard deviation Each symbol represents the value of individual mouse Horizontal lines indicate the mean value for eachgroup of animals

were detected in animals inoculated with peptide T (data notshown)

33 Incorporation of the T-Cell Epitope Is Required to ElicitIgG2 Responses We next investigated the ability of thedifferent peptides delivered subcutaneously to induce specificisotype IgG1 and IgG2aIgG2b antibodies As shown in Figure3 B2T was the construction that induced significantly higher

levels of the anti-FMDV antibodies of the three isotypes Inaddition isotyping of the anti-FMDV antibodies revealed aTh1Th2 balanced profile when the peptides harbour the T-cell epitope in a suitable orientation Thus animals immu-nized with peptides TB and B did not show specific IgG2btiters and only one of the mice immunized with peptide B

elicited IgG2a titersThese results suggest that class-switching(production of IgG2a and IgG2b) of the FMDV antibodiesinduced by linear peptides requires the cooperation of CD4+lymphocytes On the other hand multimerization of the B-cell epitope in the T-cell epitope-containing divalent den-drimers results in improved titers of the three IgG isotypes

34 Multiple Presentation of the B-Cell Epitope EnhancesSystemic and Local Specific IgA Responses To investigate thecapacity of the peptides assessed to elicit systemic and localspecific IgA responses serum samples and nasal fluids wereanalysed by an IgA-specific ELISA (Figure 4)The higher IgAresponses in most of the immunized mice were elicited bymultimeric peptides (B

4T and B

2T) Statistical differences


BT TB B0

1

2

3

4

5

Peptides

lowastlowast

lowastlowast

lowast

B4T B2T

Sera

IgA

tite

rs (l

og10

)

(a)

BT TB B00

05

10

15

Peptides

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowast

Nas

al Ig

A ti

ters

(OD

450

)

B4T B2T

(b)

Figure 4 Systemic (serum) and local (nasal) IgA antibody responses to FMDV determined by ELISA at day 39 postimmunization (a) IgAantibody titers against FMDV Endpoint titers were expressed as described in Figure 3 Each symbol represents the value for an individualmouse Horizontal lines indicate the mean value for each group of animals (b) IgA antibody titers against FMDV determined in nasal fluidsTiters are expressed as the OD at 450 nm value obtained using a 1 10 dilution

were found between FMDV-specific IgA antibodies titerselicited by peptides B

2T and B

4T and the three monomeric

peptides but not between both dendrimeric constructions(Figure 4)Thus multimerization of the B-cell epitope resultsin an improvement of both sera and nasal specific IgA titers

35Multiple Presentation of the B-Cell Epitope Improves T-CellMediated IFN-120574 Release Freshly collected splenocytes werestimulated in vitro with either the immunizing peptide orFMDV After 48 h incubation cells were harvested and theiractivation was analyzed by an IFN-120574 ELISPOT assay All thesynthetic peptides including that corresponding to the T-cellepitope were able to induce significant release of this cytokineafter in vitro recall with the corresponding antigens peptideand virus (Figure 5)The highest release of IFN-120574 in responseto in vitro recall with FMDV was induced by B

4T followed

by B2T construction However when the corresponding

peptides were used as in vitro stimuli IFN-120574 release washigher induced by B

2T peptide Differences with monomeric

peptides were statistically significant between B2T andor

B4T versus BT TB and B after stimulation with peptide

and virus respectively Only 3 out of 6 animals immunizedwith linear peptides were responders in the ELISPOT assaywhile all the dendrimeric peptide-immunized mice releaseddetectable quantities of IFN-120574

4 Discussion

The development of successful peptide vaccines has beenlimited mainly by difficulties associated with in vivo stabilitypoor immunogenicity of linear peptides and by the MHC

polymorphism of the host species [23 24] However recentadvances on the requirements for induction andmaintenanceof immune responses as well as on the pharmacokinetics ofpeptides have provided new strategies to enhance both pep-tide immunogenicity and stability and thus returned peptide-based technologies to the forefront of vaccine design [9 10]

The epitope density of a single antigen molecule isconvincingly regarded as a selfnon-self-discriminator ofhumoral responses [25 26] Usually repetitive viral surfaceantigens of high epitope density induce efficient direct cross-linking of the surface Ig receptors of immature B cellswhereas monomeric antigens of low epitope density ratherinduce apparent B-cell tolerance [25 26]This effect togetherwith the facilitation of antigen internalization in antigenpresenting cells (APC) such as dendritic cells has beenproposed as an explanation for the ability of multimericpresentations to trigger an efficient antibody response [27]In line with this multimerization approach we previouslyreported full protection against FMDV following vaccinationof pigs with dendrimeric peptides (B

4T) displaying B- and

T-cell epitopes of FMDV serotype C [18] However thesame B and T epitopes juxtaposed colinearly elicited onlypartial protection highlighting the relevance of T-cell epitopeinsertion and multimeric presentation [17]

To extend this proof of concept to epidemiologically rele-vant FMDV serotypes in the present study we havedesigned new linear and dendrimeric peptides bearingtype O FMDV B-cell epitope sequences (from the GHloop of VP1) and the same T-cell epitope used in previousstudies [16ndash18] which is highly conserved among FMDVserotypes [28] We have explored the contribution to


immunogenicity of T-cell epitope incorporation in typeO FMDV linear monomeric peptides by analyzing howthe lack of such T-cell epitope (peptide B) or the N- orC-terminal attachment of the T to B epitope (peptides BTan TB) affects the immune response Our results showthat T-cell epitope incorporation in monomeric peptides isessential for an efficient induction of antibodies includingdevelopment of anamnestic response and anti-FMDVneutralizing antibodies Furthermore data for the linearpeptides support that incorporation of the T-cell epitope inthe proper orientation relative to the B epitope (peptide BT)is essential for the induction of effective T-cell help Thuseither the lack of T-cell epitope or its positioning at the N-terminus of the B-cell epitope abrogates both the secondaryhumoral response after re-exposure to immunogen (Figure 1)and the induction of specific neutralizing antibodies (Figure2) Class-switching (production of IgG1 IgG2a and IgG2b) isa process that requires the contribution ofCD4+ lymphocytes[4] ImmunizationwithTBorBpeptides did not elicit specificIgG2 antibodies (Figure 3) Therefore adequate orientationof the T-cell epitope in the monomeric peptides results inboth enhanced humoral response and in a bias towards Th-1type immunity In this regard it is worth recalling that in bothlinear constructions the B and T epitopes are juxtaposednot separated by any connecting unit These two differentepitope arrangements define in fact rather different structuralpatterns in spite of identical amino acid composition Oneshould therefore not exclude that such different molecularpositioning underlies the different processing of BT and TBpeptides altering the T-cell epitope binding to MHC or therecognition of the B-cell epitopes by B cells

From these results we can conclude that in CD1 micethe immune response to this particular B-cell epitope in theGH loop of VP1 is T-cell-dependent requiring an efficientcooperation of specific CD4+ lymphocytes This result isconsistent with studies in cattle by Juleff et al [29] whofound that CD4 depletion substantially inhibited antibodyresponses to GH loop peptide VP1(135ndash156) indicatingthat responses to this particular site in cattle were T-cell-dependent Interestingly while N-terminal positioning ofthe T-cell epitope (TB peptide) failed to elicit anti-FMDVantibodies cellular responses were evoked in immunizedmice (Figure 5) This suggests that T-cell epitope orientationis only relevant for efficient B-T cooperation but does notsignificantly affect in vivo priming of peptide-specific T-cellsupon in vitro recall to release IFN120574 in response to suchstimulation (Figure 5) In this regard some questions stillremain to be addressed For example it would be interestingto determine more precisely how effector and memory Tcells are activated after immunization with the dendrimericpeptide andwhich cell subset (T NKTNK B or professionalAPCs) is responsible for IFN120574 production These analyseswould likely provide some explanation for the differencesbetween tetra- and bivalent constructions in their IFN120574response to virus or peptide This study has also confirmedour previous findings with type C FMDV dendrimeric con-structions ResultswithB

4TandB

2Tdendrimers support that

multiple presentation of the B-cell epitope is advantageousover simple juxtaposition for induction of humoral and

Peptide Virus0

50

100

150

200

250

BTTB

TBNaive

Mice groups

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast


lowastlowastlowast

lowastlowastlowast


lowastlowast

lowastlowast

lowastlowast

lowastlowast

lowastlowast

IFN120574

spot

s106

sple

nocy

tes

B4TB2T

Figure 5 Frequency of peptide- and virus-specific IFN120574-producingcells in the spleen of immunized mice IFN120574-producing cells weremeasured by ELISPOT assay in four animals from each group Cellswere stimulated with peptide (white bars) or FMDV (grey bars)Data are presented as the mean for four mice error bars representstandard deviation

cellular immune responses [17 18] Furthermore we haveshown that B

2T a downsized version of B

4T with only two

copies of the B-cell epitope elicits similar or even betterresponses [20] We still do not have an explanation for thissomewhat unexpected observation although one could con-jecture that differences in epitope multiplicitydisplay mightreduce B-cell receptor cross-linking efficiency and eventuallylower B

4T immunogenicity relative to B

2T

Dendrimeric and linear peptides also performed differ-ently with regard to IgA antibody titers As most pathogensFMDV included enter the body through mucosal surfaces[30] mucosal IgA responses are an effective front-line wayof fighting infection There is early evidence of the role ofspecific IgA in protection against FMDV [31] pointing outthat effective stimulation of mucosal IgA response would becrucial for the successful development of FMDV vaccines[17 32 33] Consistently with our previous results [18 20]FMDV type O bi- and tetravalent constructions inducedhigh mucosal responses by parenteral administration (Figure4(b)) while none of the monomeric peptides were ableto induce nasal FMDV IgA titers The natural pathway ofmucosal immune induction involves direct delivery of theimmunogen to a mucosal surface and local processing of theantigen in specialized aggregates of lymphoid tissue termedmucosal inductive sites [34 35] Stimulated lymphocytesthen migrate to the corresponding mucosal surface whereantigen-specific IgA and IgG are locally produced andspecific T cells reside to protect that mucosal surface frompathogen attack [35] In contrast to this natural induction


pathway B4T and B

2T dendrimers can induce high mucosal

immune responses by parenteral administration Alternativenonmutually exclusive mechanisms can be invoked for theproduction of secretory antibodies after parenteral adminis-tration of the antigen including (i) direct diffusion of solubleor phagocytosed antigens to mucosa-associated lymphoidtissue andor (ii) activation of antigen-presenting cells atdraining lymph nodes which then migrate to mucosa-associated lymphoid tissue [35 36]Thedendrimeric peptidesare more stimulatory for the mucosal immune system thanmonomeric peptides probably due to better targeting to den-dritic cells Taken together these results confirmdendrimericpeptides as good candidates for future mucosal vaccines ableto overcome some of the main problems associated withmucosal administration (local degradation physical ejectionof the vaccine etc) [34]

In addition to confirming that multimerization is animportant strategy in the triggering of a humoral responseherein we have shown it can also improve IFN-120574 releaseby primed splenocytes after in vitro recall Thus higherIFN-120574 release levels were observed after immunization withdendrimeric (particularly B

4T) than with linear peptides

IFN120574 a key cytokine produced primarily by NK and T cellsfacilitates host defense against intracellular pathogens [23]CD4+ T cell activation by DCs triggers their differentiationalong two distinct and mutually exclusive pathways (i) Th1-type CD4+ T cells essentially produce IFN-120574 and TNF-120572which assist in the elimination of intracellular pathogens bothdirectly (cytokine responses) and indirectly via their supporttomacrophage activation andCD8+T cell differentiation and(ii)Th2-type CD4+ T cells essentially produce IL-4 IL-5 andIL-13 which are directly involved in the defense against extra-cellular pathogens such as helminths [26] Enhanced uptakeby DCs of high epitope density antigens such as dendrimericpeptides andor their mechanism of internalization [27 37]might explain upregulated IFN-120574 production In contrastprocessing of linear peptides by other APCs (macrophagesneutrophils and B cells) not so efficient in activation of Th1responses could explain the lower IFN-120574 release levels inmice immunized with these peptides

Finally the fact that a bivalent peptide is more immuno-genic than its tetravalent congener has also importantimplications for developing cost-effective FMDV peptidevaccines Production of B

4T required exhaustive purification

and even so yielded a not-quite-homogeneous end product[18] whereas the simpler design and improved conjugationchemistry of the B

2T constructs translated into significantly

improved yields purity and hence much lower productioncosts [20] At the time of this writing it seems clear that theB2T construct shows undeniable advantages as a candidate

for a peptide-based FMDV vaccine

5 Conclusions

The above results highlight the relevance of adequatelyselecting specific B- and T-cell epitopes to be included in apeptide vaccine as well as the importance of BT cell epitoperelative positioning for successful eliciting of an immune

response In our FMDV model B-cell epitope multivalencyby means of dendrimeric constructions is shown to improveimmunogenicity including induction of mucosal IgA rela-tive to mere linear juxtaposition of B- and T-cell epitopesMoreover bivalent dendrimeric constructions elicit similaror even better immune responses than tetravalent ones

Acknowledgments

We thankBeatrizGuerra for her valuable technical assistanceResearch at CBMSO was funded by Spanish MINECO(BIO2011-24351) and by an institutional grant from Fun-dacion RamonAreces Research at Universitat Pompeu Fabrawas funded by the Spanish MINECO (SAF2011-24899) andby Generalitat de Catalunya (SGR2009-00492) Research atINIA was funded by the European Communityrsquos SeventhFramework Programme (FP7 2007-2013) Research Infras-tructures action under the grant agreement no FP7-228394(NADIR) and Spanish MINECO (AGL2010-22200-C02-02and CC07-062) Noelia Moreno is a predoctoral (FPI) fellowfrom the Spanish MEC

References

[1] A D James and J Rushton ldquoThe economics of foot and mouthdiseaserdquo Revue Scientifique et Technique vol 21 no 3 pp 637ndash644 2002

[2] J-F Valarcher Y Leforban M Rweyemamu et al ldquoIncursionsof foot-and-mouth disease virus into Europe between 1985 and2006rdquo Transboundary and Emerging Diseases vol 55 no 1 pp14ndash34 2008

[3] K Sumption M Rweyemamu and W Wint ldquoIncidence anddistribution of foot-and-mouth disease in Asia Africa andSouth America Combining expert opinion official diseaseinformation and livestock populations to assist risk assessmentrdquoTransboundary and Emerging Diseases vol 55 no 1 pp 5ndash132008

[4] L L Rodriguez and C G Gay ldquoDevelopment of vaccinestoward the global control and eradication of foot-and-mouthdiseaserdquo Expert Review of Vaccines vol 10 no 3 pp 377ndash3872011

[5] T R Doel ldquoFMD vaccinesrdquo Virus Research vol 91 no 1 pp81ndash99 2003

[6] E M Cottam J Wadsworth A E Shaw et al ldquoTransmissionpathways of foot-and-mouth disease virus in the United King-dom in 2007rdquo PLoS Pathogens vol 4 no 4 Article ID e10000502008

[7] P Kitching J Hammond M Jeggo et al ldquoGlobal FMD control-Is it an optionrdquo Vaccine vol 25 no 30 pp 5660ndash5664 2007

[8] F Sobrino and E Domingo ldquoFoot-and-mouth disease inEurope FMD is economically the most important disease offarm animals Its re-emergence in Europe is likely to have con-sequences that go beyond severe alterations of livestock produc-tion and traderdquo EMBO Reports vol 2 no 6 pp 459ndash461 2001

[9] A W Purcell J McCluskey and J Rossjohn ldquoMore than onereason to rethink the use of peptides in vaccine designrdquo NatureReviews Drug Discovery vol 6 no 5 pp 404ndash414 2007

[10] A Brun J Barcena E Blanco et al ldquoCurrent strategies for sub-unit and genetic viral veterinary vaccine developmentrdquo VirusResearch vol 157 no 1 pp 1ndash12 2011


[11] R Acharya E FryD Stuart G FoxD Rowlands and F BrownldquoThe three-dimensional structure of foot-and-mouth diseasevirus at 29 A resolutionrdquo Nature vol 337 no 6209 pp 709ndash716 1989

[12] M G Mateu and N Verdaguer ldquoFunctional and structuralaspects of the interaction of foo-and-outh disease virus withantibodiesrdquo in Foot-and-Mouth Disease Current PerspectivesF Sobrino and E Domingo Eds pp 223ndash260 Horizon Bio-science Norfolk UK 2004

[13] J L Bittle R A Houghten and H Alexander ldquoProtectionagainst foot-and-mouth disease by immunization with a chem-ically synthesized peptide predicted from the viral nucleotidesequencerdquo Nature vol 298 no 5869 pp 30ndash33 1982

[14] O Taboga C Tami E Carrillo et al ldquoA large-scale evaluation ofpeptide vaccines against foot-and-mouth disease lack of solidprotection in cattle and isolation of escape mutantsrdquo Journal ofVirology vol 71 no 4 pp 2606ndash2614 1997

[15] K C McCullough F De Simone E Brocchi L Capucci J RCrowther and U Kihm ldquoProtective immune response againstfoot-and-mouth diseaserdquo Journal of Virology vol 66 no 4 pp1835ndash1840 1992

[16] E Blanco M Garcia-Briones A Sanz-Parra et al ldquoIdentifica-tion of T-cell epitopes in nonstructural proteins of foot-and-mouth disease virusrdquo Journal of Virology vol 75 no 7 pp 3164ndash3174 2001

[17] C Cubillos B Garcia de la Torre J Barcena D Andreu FSobrino and E Blanco ldquoInclusion of a specific T cell epitopeincreases the protection conferred against foot-and-mouth dis-ease virus in pigs by a linear peptide containing an immun-odominant B cell siterdquo Virology Journal p 66 2012

[18] C Cubillos B G de la Torre A Jakab et al ldquoEnhancedmucosal immunoglobulin A response and solid protectionagainst foot-and-mouth disease virus challenge induced by anovel dendrimeric peptiderdquo Journal of Virology vol 82 no 14pp 7223ndash7230 2008

[19] K Sumption P Pinto J Lubroth et al ldquoFoot-and-Mouth dis-ease situation worldwide and major epidemiological eventsin 2005-2006rdquo FAO EMPRES Focus on 2007 httpwwwfaoorgdocseimsupload225050Focus ON 1 07 enpdf

[20] M Monso B G de la Torre E Blanco N Moreno and DAndreu ldquoInfluence of conjugation chemistry and B epitopeorientation on the immune response of branched peptideantigensrdquo Bioconjugate Chemistry vol 24 no 4 pp 578ndash5852013

[21] F Borras-Cuesta Y Fedon and A Petit-Camurdan ldquoEnhance-ment of peptide immunogenicity by linear polymerizationrdquoEuropean Journal of Immunology vol 18 no 2 pp 199ndash2021988

[22] S M Golding R S Hedger P Talbot and J Watson ldquoRadialimmuno diffusion and serum neutralisation techniques for theassay of antibodies to swine vesicular diseaserdquo Research inVeterinary Science vol 20 no 2 pp 142ndash147 1976

[23] C Leclerc ldquoNew approaches in vaccine developmentrdquo Compar-ative Immunology Microbiology amp Infectious Diseases vol 26pp 329ndash341 2003

[24] D Rowlands ldquoFoot-and-mouth disease virus peptide vaccinesrdquoin Foot-and- Mouth Disease Current Perspectives F Sobrinoand E Domingo Eds pp 335ndash354 Horizon Bioscience Nor-folk UK 2004

[25] M F Bachmann U H Rohrer T M Kundig K Burki HHengartner and R M Zinkernagel ldquoThe influence of antigen

organization on B cell responsivenessrdquo Science vol 262 no5138 pp 1448ndash1451 1993

[26] R M Zinkernagel ldquoOn natural and artificial vaccinationsrdquoAnnual Review of Immunology vol 21 pp 515ndash546 2003

[27] A Gamvrellis D Leong J C Hanley S D Xiang P Mottramand M Plebanski ldquoVaccines that facilitate antigen entry intodendritic cellsrdquo Immunology and Cell Biology vol 82 no 5 pp506ndash516 2004

[28] C Carrillo E R Tulman G Delhon et al ldquoComparativegenomics of foot-and-mouth disease virusrdquo Journal of Virologyvol 79 no 10 pp 6487ndash6504 2005

[29] N Juleff M Windsor E A Lefevre et al ldquoFoot-and-mouthdisease virus can induce a specific and rapid CD4+ T-cell-independent neutralizing and isotype class-switched antibodyresponse in naıve cattlerdquo Journal of Virology vol 83 no 8 pp3626ndash3636 2009

[30] K C McCullough and F Sobrino ldquoImmunology of foot-and-mouth diseaserdquo in Foot-and-Mouth Disease Current Perspec-tives F Sobrino and E Domingo Eds pp 173ndash222 HorizonBioscience Norfolk UK 2004

[31] M J Francis and L Black ldquoAntibody response in pig nasalfluid and serum following foot-and-mouth disease infection orvaccinationrdquo Journal of Hygiene vol 91 no 2 pp 329ndash334 1983

[32] D Fischer D Rood R W Barrette et al ldquoIntranasal immu-nization of guinea pigs with an immunodominant foot-and-mouth disease virus peptide conjugate induces mucosal andhumoral antibodies and protection against challengerdquo Journalof Virology vol 77 no 13 pp 7486ndash7491 2003

[33] P L Eble A Bouma K Weerdmeester J A Stegeman andA Dekker ldquoSerological and mucosal immune responses aftervaccination and infection with FMDV in pigsrdquo Vaccine vol 25no 6 pp 1043ndash1054 2007

[34] J Holmgren and C Czerkinsky ldquoMucosal immunity and vac-cinesrdquo Nature Medicine vol 11 no 4 pp S45ndashS53 2005

[35] P Brandtzaeg ldquoInduction of secretory immunity and memoryat mucosal surfacesrdquo Vaccine vol 25 no 30 pp 5467ndash54842007

[36] J-P Bouvet N Decroix and P Pamonsinlapatham ldquoStim-ulation of local antibody production parenteral or mucosalvaccinationrdquo Trends in Immunology vol 23 no 4 pp 209ndash2132002

[37] L M Silva-Flannery M Cabrera-Mora M Dickherber and AMoreno ldquoPolymeric linear peptide chimeric vaccine-inducedantimalaria immunity is associated with enhanced in vitroantigen loadingrdquo Infection and Immunity vol 77 no 5 pp 1798ndash1806 2009

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013

Oxidative Medicine and Cellular Longevity

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

The Scientific World Journal

International Journal of

EndocrinologyHindawi Publishing Corporationhttpwwwhindawicom

Volume 2013

ISRN Anesthesiology


OncologyJournal of


PPARRe sea rch


OphthalmologyJournal of


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BioMed Research International


ObesityJournal of


ISRN Addiction



Computational and Mathematical Methods in Medicine

ISRN AIDS


Clinical ampDevelopmentalImmunology

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2013

Diabetes ResearchJournal of


Evidence-Based Complementary and Alternative Medicine

Volume 2013Hindawi Publishing Corporationhttpwwwhindawicom


Gastroenterology Research and Practice


ISRN Biomarkers


MEDIATORSINFLAMMATION

of


candidates for next-generation vaccines and peptides aretypically poorly immunogenic

In the case of FMD the main antigenic sites recognizedby B lymphocytes have been identified at defined structuralmotifs exposed on the surface of the FMDV capsid whoseamino acid sequences accumulate variations among differentserotypes [11 12] A continuous immunodominant B-cellsite located in the GH loop around positions 140 to 160 ofcapsid protein VP1 has been widely used as an immunogenicpeptide [13] However the protection against FMD conferredto natural hosts by linear peptides spanning the GH loopof VP1 is limited [13 14] Although it is generally acceptedthat protective immunity to FMDV is mostly due to neu-tralizing antibodies a T-cell response is also necessary foreffective immunity [15] We have reported that inclusion ofa specific T-cell epitope located in residues 21 to 35 of FMDVNS protein 3A [16] juxtaposed in a linear fashion to theabove-mentioned B-cell epitope affords significant reductionin virus excretion and clinical scores after challenge [17]This monomeric peptide B-T however did not afford fullprotection in challenged pigs

In order to enhance the effectiveness of presentation ofthe above B- and T-cell epitopes to the immune systema multimerization approach consisting of a dendrimericpeptide bearing four copies of the B-cell epitope and oneof the Th epitope was explored The branched constructgenerically known as B

4T elicited high titers of FMDV-

neutralizing and IgA antibodies in both pig and outbredmice (CD1 strain) activated T-cells and induced IFN120574 releaseThe dendrimer performed as an effective peptide vaccineconferring solid protection in swine against type C FMDVchallenge [18]

With a view to extending these proof-of-conceptresults to epidemiologically relevant FMDV serotypes wehave designed and produced new B

4T constructs harbor-

ing sequences from type O FMDV (currently the mostwidespread serotype) [3 19] as B-cell epitopes To assess therelevance of B-cell epitope multivalency constructs bearingtwo (B

2T) or four (B

4T) copies of the B-cell epitope were

tested in CD1 mice showing that multivalency is advant-ageous over simple B-T-epitope juxtaposition but also thatbivalent B

2T constructions elicit similar or even better

humoral and cellular specific responses than tetravalent ones[20] Herein we show that epitope density is essential forinducing an efficient humoral immune response includingneutralizing antibodies but also for optimal release ofIFN120574 a relevant antiviral cytokine In addition we evaluatethe orientation of T-relative to B-cell epitopes in juxta-posed monovalent constructs in terms of efficient T-Bcell cooperation and induction of cellular response Takentogether our results provide useful insights for a more accu-rate design of subunit vaccines

2 Materials and Methods

21 Peptides Peptides reproducing the B [VP1(136ndash150)] andT [3A(21ndash35)] epitopes of type O FMDV (O-UKG 1101) indifferent arrangements are shown in Table 1 Linear B T BTand TB peptides were made by Fmoc solid phase synthesis as

previously described [17] Bi- and tetravalent constructs B2T

and B4Tweremade by thioether ligation protocols as detailed

in Monso et al [20] and Cubillos et al [18] respectively Allsix peptides were purified by reverse phase HPLC to gt95purity and satisfactorily characterized by MALDI-TOF massspectrometry

22 Virus A virus stock derived from serotype O-UKG 1101(supplied by The Pirbright Institute UK) by two amplifi-cations in IBRS-2 cells which maintained the consensussequences at the capsid protein region was used in this study

23 Mice and Immunization The immune response inducedby the various peptide constructions on Table 1 was assessedin outbred Swiss mice (Swiss ICR-CD1 Harlan Laboratories)5- to 6-week-old female mice in groups of 6 to 9 were main-tained under standard housing conditions in the CBMSOAnimal Care unit Mice were immunized subcutaneouslyat days 0 and 18 with 100 120583g of each peptide emulsified inMontanide ISA 50V2 (Seppic France) and sacrificed at day39 Two groups of 4 mice each were immunized as controlswith either adjuvant or PBS Blood samples were collected bytail bleeding before priming (day 0) and at days 14 20 and39 (sacrifice) All experimental procedures were conductedin accordancewith protocols approved by theCBMSO ethicalcommittee

24 Virus Neutralization Test (VNT) Virus neutralizationactivity was determined in sera by a standard microneutral-ization test performed in 96-well plates by incubating serialtwofold dilutions of each serum sample with 100 50 tissueculture infective dose (TCID50) of FMDVO-UK01 for 1 h at37∘CThe remaining viral activity was determined in 96-wellplates containing freshmonolayers of BHK-21 cells Endpointtiters were calculated as the reciprocal of the final serumdilution that neutralized 100 TCID50 of FMDV (O-UK01)in 50 of the wells [22]

25 Detection of Specific Anti-FMDV Antibodies By ELISATotal antibodies against FMDV were examined by ELISAin serum samples collected at day 39 Briefly Maxisorp 96-well plates (Nunc) were coatedwith sucrose gradient-purified140rsquos FMDV O UKG 112001 particles in PBS overnight at4∘C (01120583gwell) Then wells were washed with PBS andblocked with 5 skimmed milk in PBS for 2 h at 37∘CDuplicate threefold dilution series of each serum sample wereprepared starting at 1100 and made up at 50 120583L Preim-mune sera from peptide-immunized mice and sera fromnonimmunized animals were used as negative controls Spe-cific antibodies were detected with horse radish peroxidase-(HRP-) conjugated goat anti-mouse IgG (Zymed Invitro-gen) diluted 13000 Colour development was obtained afteraddition of 100 120583Lwell of the soluble substrate 331015840551015840-tetramethylbenzidine (TMB Sigma) and stopped by an equalvolume of 1M H

2SO4 Plates were read in a Fluostar Omega

microplate reader at 450 nm In this assay it was found thatthe point on the titration curve corresponding to an A

450of

10 invariably fell on the linear part of the curve Antibodytiters were therefore expressed as the reciprocal of the last


Table 1









O

O







O

O

O

O

K

K










2and




0 14 20 390

1

2

3

4

5

TBB

BT


B4TB2T

FMD

V an

tibod

y tit

ers (

log1

0)




3 Results


2T and B

4T


2B and T




10) anti-FMDV




BT TB B0

1

2

3

Peptides


B4T B2T

VN

T (lo

g10

)


50of homolo-



values









2T group was even








BT TB B0

2

4

6

Peptides

lowast

lowastlowast

lowastlowast

lowastlowast

IgG1

titer

s (lo

g10

)

B4T B2T

(a)

BT TB B0

2

4

6

Peptides

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

IgG2

a tite

rs (l

og10

)

B4T B2T

(b)

BT TB B0

2

4

6

Peptides


IgG2

b tit

ers (

log1

0)

B4T B2T

(c)









4T and B



BT TB B0

1

2

3

4

5

Peptides

lowastlowast

lowastlowast

lowast

B4T B2T

Sera

IgA

tite

rs (l

og10

)

(a)

BT TB B00

05

10

15

Peptides

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowast

Nas

al Ig

A ti

ters

(OD

450

)

B4T B2T

(b)



2T and B




4T followed







4 Discussion










4TandB



Peptide Virus0

50

100

150

200

250

BTTB

TBNaive

Mice groups

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast



lowastlowastlowast

lowastlowastlowast


lowastlowast

lowastlowast

lowastlowast

lowastlowast

lowastlowast

IFN120574

spot

s106

sple

nocy

tes

B4TB2T




4T with only two



2T



pathway B4T and B












5 Conclusions



Acknowledgments


References















































Volume 2013

ISRN Anesthesiology


OncologyJournal of


PPARRe sea rch




ISRN Allergy




ObesityJournal of


ISRN Addiction




ISRN AIDS




Volume 2013








ISRN Biomarkers



of


Table 1









O

O







O

O

O

O

K

K










2and




0 14 20 390

1

2

3

4

5

TBB

BT


B4TB2T

FMD

V an

tibod

y tit

ers (

log1

0)




3 Results


2T and B

4T


2B and T




10) anti-FMDV




BT TB B0

1

2

3

Peptides


B4T B2T

VN

T (lo

g10

)


50of homolo-



values









2T group was even








BT TB B0

2

4

6

Peptides

lowast

lowastlowast

lowastlowast

lowastlowast

IgG1

titer

s (lo

g10

)

B4T B2T

(a)

BT TB B0

2

4

6

Peptides

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

IgG2

a tite

rs (l

og10

)

B4T B2T

(b)

BT TB B0

2

4

6

Peptides


IgG2

b tit

ers (

log1

0)

B4T B2T

(c)









4T and B



BT TB B0

1

2

3

4

5

Peptides

lowastlowast

lowastlowast

lowast

B4T B2T

Sera

IgA

tite

rs (l

og10

)

(a)

BT TB B00

05

10

15

Peptides

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowast

Nas

al Ig

A ti

ters

(OD

450

)

B4T B2T

(b)



2T and B




4T followed







4 Discussion










4TandB



Peptide Virus0

50

100

150

200

250

BTTB

TBNaive

Mice groups

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast



lowastlowastlowast

lowastlowastlowast


lowastlowast

lowastlowast

lowastlowast

lowastlowast

lowastlowast

IFN120574

spot

s106

sple

nocy

tes

B4TB2T




4T with only two



2T



pathway B4T and B












5 Conclusions



Acknowledgments


References















































Volume 2013

ISRN Anesthesiology


OncologyJournal of


PPARRe sea rch




ISRN Allergy




ObesityJournal of


ISRN Addiction




ISRN AIDS




Volume 2013








ISRN Biomarkers



of


0 14 20 390

1

2

3

4

5

TBB

BT


B4TB2T

FMD

V an

tibod

y tit

ers (

log1

0)




3 Results


2T and B

4T


2B and T




10) anti-FMDV




BT TB B0

1

2

3

Peptides


B4T B2T

VN

T (lo

g10

)


50of homolo-



values









2T group was even








BT TB B0

2

4

6

Peptides

lowast

lowastlowast

lowastlowast

lowastlowast

IgG1

titer

s (lo

g10

)

B4T B2T

(a)

BT TB B0

2

4

6

Peptides

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

IgG2

a tite

rs (l

og10

)

B4T B2T

(b)

BT TB B0

2

4

6

Peptides


IgG2

b tit

ers (

log1

0)

B4T B2T

(c)









4T and B



BT TB B0

1

2

3

4

5

Peptides

lowastlowast

lowastlowast

lowast

B4T B2T

Sera

IgA

tite

rs (l

og10

)

(a)

BT TB B00

05

10

15

Peptides

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowast

Nas

al Ig

A ti

ters

(OD

450

)

B4T B2T

(b)



2T and B




4T followed







4 Discussion










4TandB



Peptide Virus0

50

100

150

200

250

BTTB

TBNaive

Mice groups

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast



lowastlowastlowast

lowastlowastlowast


lowastlowast

lowastlowast

lowastlowast

lowastlowast

lowastlowast

IFN120574

spot

s106

sple

nocy

tes

B4TB2T




4T with only two



2T



pathway B4T and B












5 Conclusions



Acknowledgments


References















































Volume 2013

ISRN Anesthesiology


OncologyJournal of


PPARRe sea rch




ISRN Allergy




ObesityJournal of


ISRN Addiction




ISRN AIDS




Volume 2013








ISRN Biomarkers



of


BT TB B0

2

4

6

Peptides

lowast

lowastlowast

lowastlowast

lowastlowast

IgG1

titer

s (lo

g10

)

B4T B2T

(a)

BT TB B0

2

4

6

Peptides

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

IgG2

a tite

rs (l

og10

)

B4T B2T

(b)

BT TB B0

2

4

6

Peptides


IgG2

b tit

ers (

log1

0)

B4T B2T

(c)









4T and B



BT TB B0

1

2

3

4

5

Peptides

lowastlowast

lowastlowast

lowast

B4T B2T

Sera

IgA

tite

rs (l

og10

)

(a)

BT TB B00

05

10

15

Peptides

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowast

Nas

al Ig

A ti

ters

(OD

450

)

B4T B2T

(b)



2T and B




4T followed







4 Discussion










4TandB



Peptide Virus0

50

100

150

200

250

BTTB

TBNaive

Mice groups

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast



lowastlowastlowast

lowastlowastlowast


lowastlowast

lowastlowast

lowastlowast

lowastlowast

lowastlowast

IFN120574

spot

s106

sple

nocy

tes

B4TB2T




4T with only two



2T



pathway B4T and B












5 Conclusions



Acknowledgments


References















































Volume 2013

ISRN Anesthesiology


OncologyJournal of


PPARRe sea rch




ISRN Allergy




ObesityJournal of


ISRN Addiction




ISRN AIDS




Volume 2013








ISRN Biomarkers



of


BT TB B0

1

2

3

4

5

Peptides

lowastlowast

lowastlowast

lowast

B4T B2T

Sera

IgA

tite

rs (l

og10

)

(a)

BT TB B00

05

10

15

Peptides

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowast

Nas

al Ig

A ti

ters

(OD

450

)

B4T B2T

(b)



2T and B




4T followed







4 Discussion










4TandB



Peptide Virus0

50

100

150

200

250

BTTB

TBNaive

Mice groups

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast



lowastlowastlowast

lowastlowastlowast


lowastlowast

lowastlowast

lowastlowast

lowastlowast

lowastlowast

IFN120574

spot

s106

sple

nocy

tes

B4TB2T




4T with only two



2T



pathway B4T and B












5 Conclusions



Acknowledgments


References















































Volume 2013

ISRN Anesthesiology


OncologyJournal of


PPARRe sea rch




ISRN Allergy




ObesityJournal of


ISRN Addiction




ISRN AIDS




Volume 2013








ISRN Biomarkers



of




4TandB



Peptide Virus0

50

100

150

200

250

BTTB

TBNaive

Mice groups

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast



lowastlowastlowast

lowastlowastlowast


lowastlowast

lowastlowast

lowastlowast

lowastlowast

lowastlowast

IFN120574

spot

s106

sple

nocy

tes

B4TB2T




4T with only two



2T



pathway B4T and B












5 Conclusions



Acknowledgments


References















































Volume 2013

ISRN Anesthesiology


OncologyJournal of


PPARRe sea rch




ISRN Allergy




ObesityJournal of


ISRN Addiction




ISRN AIDS




Volume 2013








ISRN Biomarkers



of


pathway B4T and B












5 Conclusions



Acknowledgments


References















































Volume 2013

ISRN Anesthesiology


OncologyJournal of


PPARRe sea rch




ISRN Allergy




ObesityJournal of


ISRN Addiction




ISRN AIDS




Volume 2013








ISRN Biomarkers



of





































Volume 2013

ISRN Anesthesiology


OncologyJournal of


PPARRe sea rch




ISRN Allergy




ObesityJournal of


ISRN Addiction




ISRN AIDS




Volume 2013








ISRN Biomarkers



of

blanco et al 2013 b epitope multiplicity and b/t epitope orientation influence immunogenicity of...

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