Download - Immunization ATUL
-
8/2/2019 Immunization ATUL
1/26
Immunization
-
8/2/2019 Immunization ATUL
2/26
Approach for prevention of
infectious diseases
Improvement and maintenance of good
socioeconomic conditions
Preventive engineering Prompt management
Surveillance and diagnostic awareness
Immunization
-
8/2/2019 Immunization ATUL
3/26
Rationale of Immunization
The objective is to produce, without harm
to the recipients a degree of resistance
sufficient to prevent a clinical attack of the
natural infection and to prevent the spread
of infections to susceptible in the
community.
-
8/2/2019 Immunization ATUL
4/26
Passive immunization
1) Artificial passive immunization
Homologous
Heterologus
2) Immunoglobulins
-
8/2/2019 Immunization ATUL
5/26
Active immunization
Vaccines are of various types Attenuated whole cell vaccine Killed whole cell vaccine
Toxoids Recombinant vaccines Subunit vaccines Conjugated vaccines
DNA based vaccines Anti idiotype vaccines Plant based vaccines
-
8/2/2019 Immunization ATUL
6/26
Properties of an ideal vaccine
Promotes effective immunity
Confers lifelong protection
Safe ( no side effects) Stable
Cheap
Seen to be good and effective by thepublic
-
8/2/2019 Immunization ATUL
7/26
Live vaccine
Viral attenuation Serial passage in cell culture. Eg Polio,
Measles, Mumps
Variants from other species. eg Smallpox,
Rotavirus
Resorted genomes. Eg Rota virus, Influenza
Temperature selected mutants. Eg Influenza
Recombinant virus. Eg HSV
Recombinant viral vector. Eg Vaccinia,
Adenovirus
-
8/2/2019 Immunization ATUL
8/26
Live vaccine - Bacterial
Serial subculture BCG
Recombinant Bacteria Eg S typhi (Ty21a)
Recombinant bacterial vector Eg Salmonella,Vibrio
-
8/2/2019 Immunization ATUL
9/26
Live vaccine - Advantages
They activate all phases of immune
system.
They raise immune response to all
protective antigens.
They offer more durable immunity and are
more cross-reactive.
They cost less to produce
They give quick immunity in majority of
vaccinees
Administration is easy
They can lead to elimination of wild type
-
8/2/2019 Immunization ATUL
10/26
Live vaccine Disadvantages
Mutation. This may lead to reversion to virulence Spread of the vaccine virus that is not
standardized and may be mutated
Sometimes there is poor "take" in tropics
Cannot be administered to patients with
immunodeficiency.
-
8/2/2019 Immunization ATUL
11/26
Killed Vaccine
Whole Cell
Bacteria Pertusis, Cholera
Virus Polio, Rabies
Protein based
Natural Hepatitis B
Chemically inactivated TT & DT
Genetically inactivated Pertusis
Recombinant polypeptide Hepatitis B
-
8/2/2019 Immunization ATUL
12/26
Killed Vaccine
Peptide based eg Malaria, Anti Fertility
Polysaccharide based - Hemophilus influenzae b
(Hib), Pneumococcal and Meningococcal
-
8/2/2019 Immunization ATUL
13/26
Killed vaccine - Advantages
They give sufficient humoral immunity if boosters
given
There is no mutation or reversion (This is a bigadvantage)
They can be used with immuno-deficient patients
Sometimes they perform better in tropical areas
-
8/2/2019 Immunization ATUL
14/26
Killed vaccine - Disadvantages
Some vaccinees do not raise immunity
Boosters tend to be needed
There is little mucosal / local immunity (IgA)
Higher cost
failures in inactivation leading to immunization
with virulent virus eg Smallpox
-
8/2/2019 Immunization ATUL
15/26
Newer Strategies - DNA based vaccination
Based on the deliberate introduction of a DNAplasmid into the vaccinee.
The plasmid carries a protein-coding gene that
transfects cells in vivo at very low efficiency and
expresses an antigen that causes an immune
response.
-
8/2/2019 Immunization ATUL
16/26
-
8/2/2019 Immunization ATUL
17/26
DNA vaccination - Advantages
Plasmids are easily manufactured in large amounts
DNA is very stable
Storage and transport are straight forward
Sequence can be changed easily in the laboratory.
Antigen produced by this method behaves in the same
way as antigen produced in natural infection would
behave
The plasmid does not replicate
-
8/2/2019 Immunization ATUL
18/26
DNA vaccination - Problems
Potential integration of plasmid into host genome
leading to insertional mutagenesis
Induction of autoimmune responses (e.g.pathogenic anti-DNA antibodies)
Induction of immunologic tolerance
-
8/2/2019 Immunization ATUL
19/26
Newer Strategies Anti idiotype antibodies
Idiotype - unique amino acid structure in the
antibody complementary to epitope is
known as the idiotype
-
8/2/2019 Immunization ATUL
20/26
antibody
New methods
Anti-idiotype vaccine
epitope
Antibody
with epitopebinding site
Virus
-
8/2/2019 Immunization ATUL
21/26
Antibodies (anti-ids) can be raised against
the idiotype by injecting the antibody into
another animal, these anti idiotype antibodieshave a structure that mimics antigenic epitope
structure.
-
8/2/2019 Immunization ATUL
22/26
antibody
Anti-idiotype vaccine cont
Make antibody
against antibody
idiotype
Anti-idiotype
antibody
Anti-idiotype
antibody mimics
the epitope
-
8/2/2019 Immunization ATUL
23/26
The anti-idiotype antibody is injected into a
vaccinee, anti-anti-idiotype antiobodies are
formed that recognize a structure similar to partof the virus and might potentially neutralize the
virus
A i idi ib d
-
8/2/2019 Immunization ATUL
24/26
Anti-anti-idiotype
antibody
Anti-idiotype antibody cont2
Use anti-idiotype antibody as
injectable vaccine
Antibody to anti-
idiotype
antibody
Binds andneutralizes virus
Anti-idiotype
antibody
Anti-anti-idiotype
antibody
Anti-anti-idiotypeantibody
Use as
vaccine
-
8/2/2019 Immunization ATUL
25/26
-
8/2/2019 Immunization ATUL
26/26