Digging up the Bones Microbiology

IMMUNOLOGY Type I Hypersensitivity reaction (anaphylactic and atopic)

Get reaction second time stung by bee; pre-existing IgE antibody specific for bee venom is made on first sting. Rash Hives IgE binds (Fe portion) to basophils and mast cells (Fe receptors).

Type II Hypersensitivity reaction - (Cytotoxic) IgM/IgG bind to cell antigen: lysis and phagocytosis. (i.e., Goodpastures) Antibody can bind and lead to basement membrane damage. Antibody can inappropriately excite TSH receptor. Deposit complement on glomerular basement membrane.

Myasthenia Gravis, Immuno thrombocytopenia purpura, hemolytic anemia, bullous pemphigoid and Graves disease. (NOT urticaria)

Type III Hypersensitivity reaction - (Immune Complexes)

Immune complexes lodge in a tissue and cause damage. Antibody is complement activating antibody. Ag-Ab complexes deposited Hypersensitivity pneumonitis, Systemic Lupus Erythematosus (lip swelling, skin rash, fever, inflammation of kidneys and joint pains), Arthus reaction, Serum sickness

Type IV Hypersensitivity reaction - (Cell-mediated, delayed type)

Delayed Type Hypersensitivity (DTH). CD4 is DTH T-cell MIF is a mediator of DTH. Examples: Allergic contact dermatitis/TB skin test. Part of normal immunity. After recognize antigen, T cells release lymphokines and activate macrophages.

Paratope - Antibody Combining site; the part of the antibody that binds to the

antigenic determinant. Epitope - Antigenic determinant. (On a complex antigen.) Bacterial DNA May contain integrated sex plasmids and prophage

Peptidoglycan Cell wall prevents rupture and gives shape.

Gram +, is thick but is susceptible to lysozyme. Resistance to osmotic shock. Gives rigidity of membrane.

Cell membrane No sterols except mycobacterium Bacteriophage - That replicate their nucleic acid by means of a replicative intermediate (or replicative form) would be expected to contain: ssDNA ssRNA Repair of damaged bacterial DNA by photoreactivation (photolyase)

Does NOT require a DNA polymerase nor an excision of about 20 nucleotides adjacent to the lesion

Missense mutation - Would most likely be associated with a formation of a mutant bacterial protein which is weakly functional (partially active) DNA transcription and DNA replication Both require Nucleoside triphosphates (not DNA polymerase III) Microorganisms - Can be both eukaryotic and prokaryotic Sigma factor - Specificity for promotor site recognition resides with this factor of bacterial RNA polymerase Mutation in the deletion of 1 base pair in the middle of a structural gene coding for a polypeptide Results in changes in several amino acid residue within that polypeptide. Establishment of the state of lysogeny requires functional host bacterial cell ATP synthesis, ribosomes Ouchterlony test Infection of a sensitive bacterial culture with a temperate bacteriophage might result in: Lysis of some of the cells

IgA O IgG O O O IgM Anti- IgG

Lysogenic (phage) conversion of some of the cells Transformation In bacteria uptake naked DNA from solution into the cell. Bacteria could acquire transposons (No F factor needed) Specialized transducing phage Contains both phage and bacterial DNA Can result in naturally formed recombinant DNA Arises after aberrant excision of lysogen. (NO sex factor needed) Transduction Requires a bacteriophage, (NOT a sex or fertility plasmid) Requires bacterial virus Co transduction

Map bacterial genes by random breakage of chromosome during phage lytic growth.

Conjugation

Can result in passage of phage DNA from donor to recipient [F (fertility) factor].

Bacterial conjugation and bacterial transduction

Differ in range of size of exogenetic DNA, (but dont differ in requirement that the transferred genes be recombined by rec.-A mediated recombination) With bacteria that have abruptly acquired resistance to several antibiotics the same resistance genes may be passed to recipient bacteria by these ways.

Transduction passes transposons from bacterial cell to bacterial cell. Transducing DNA

Found only in one cell within a colony arising following an abortive transduction event

Transformation (NOT conjugation) Bacterial gene transfer mechanism, used often to select recombinant DNA

molecules. Lysogenization Phage to prophage requiring ATP and ribosomes. Example is diphtheria toxin. Lysogenic (temperate) vs Lylic (virulent) bacteriophage Different capacity to synthesize functional phage repressor protein.

Lytic bacteriophage replication requires host ATP and RNA polymerase. dgal Virus formed by aberrant excision of a prophage. Hfr formation Integrates F into the chromosome. During bacterial conjugation, acts as a donor of chromosomal DNA. Cannot transfer prokaryolic genes among bacteria by meiosis nor mitosis. Phage chromosomes

Some contain only single-stranded RNA, some may be so small they have genetic information sufficient for only 3 or 4 protein molecules.

Phage repressor protein

Ability to code for this is expected to differ in temperate and virulent phage

Phage restriction endonuclease appears in:

Successful genetic recombination (after bacterial conjugation) was observed to drop nearly 1000 fold following lysogenization of recipient (F-) E. coli cells with P1 phage.

E. coli high frequency of recombination (Hfr) strain Does NOT contain an extrachromosomal sex plasmid Does NOT act as a recipient in bacterial conjugation R factors in E. coli contain both: Transposons and an element analogous to the sex (fertility) plasmid F. Some plasmids May not be able to initiate bacterial conjugation May be carried within the head of a bacteriophage Generalized transducing particles Contain bacterial genes (but not phage genes) Antibody and macrophages (not cytotoxic T-lymphocytes, nor Natural Killer cells) Most important in host defense against extracellular invaders Mal Ser E. coli grows on : Glucose and 1 amino acid Serine media. When separating lymphocytes on a density gradient Lymphocytes are separated from red blood cells (not monocytes). Red blood cells are more dense than lymphocytes

Immunoelectrophoresis - Detects monoclonal gammopathy RID - Quantitative gel diffusion Immunofluorescence - Fluorescent labeled antibody binds to tissue antigen ELISA - Enzyme-Substrate reactions; measures the changes

in color, (NOT the radioisotope) Not done in antigen excess. Western Blot - Definitive evidence for AIDS RAST assay - Measures specific antibodies against allergens, skin

test results. The mouse Class 1 MHC: H-2K and H-2D A nude mouse has no thymus The mouse MHC is called H-2 Syngeneic mice are genetically identical HLA-D Is called the immune response region in man. It codes for antigens Important in cell-cell communication (Not code for

class I Ags) Its antigens are present on -cells. (does NOT code for certain complement proteins) An assay for HLA-A, B, -C typing performed by cytotoxicity testing requiring- Abs to known alleles to MHC Trypan blue,

Complement, (not cytotoxic T-lymphocytes) May prevent Graft vs. Host disease which can result from bone marrow transplantation Match MHC antigens of host and donor before transplantation Pretreat bone marrow to remove mature T-lympocytes prior to

transplantation. (Not remove all lymphoid cells and precursors from the marrow prior to

transplantation, not use bone marrow from the mother for the transplantation) Hyperacute graft rejection results when Preformed antibodies prevent the graft from taking

Second set graft rejection is faster that First set rejection because: Memory cells are present to facilitate a rapid response MHC antigens are codominantly expressed every cell that expresses antigen expresses both alleles. T-cells see antigen in the context of MHC antigens. CD2: Receptor for Sheep Red Blood Cells (SRBC) On majority of T-lymphocytes. Is a monoclonal antibody that binds to SRBC receptor on thymocytes. T11. CD3: T-cell receptor associated complex. CD4: Helper cell, Small cortical thymocyte CD8: Suppressor cell, Small cortical thymocyte SRBC receptor: CD2, T11, T cells. (NOT Fe receptor). Valence - Number of binding sites Class - Isotype Suppressor T-cells Regulate immune responses. Express CD8+ (human) or Lyt 23+ (mouse) antigens. Exert effects on helper T-cells, and B-cells to inhibit immune response. CD3+, CD2+ (NOT activated by helper or inducer T-cells.) Helper T-cells CD4+ CD3+ CD2+ Lyt 1+23(-). B-Lymphocytes Triggered by: Antigen binding to surface immunoglobulin, Activated T helper cells. Helper factors IL-1, IL-2, and BCGE. Macrophages Have a role in induction and amplification of immune response by: Presenting antigen in an appropriate form to B and T-cells.

Expressing receptors for C3b, Fe part of IgG,m and lymphokines on their membranes.

(NOT secreting lymphokines, and NOT by expression of antigen-specific receptors on membranes.)

Macrophages and Neutrophils Both have C3 receptors. Both respond to chemotactic factors. Both use lysosomal enzymes to kill bacteria. Macrophages generate oxygen radical less efficiently than neutrophils. (Both can NOT present antigens to T-cells). Class I MHC Cytotoxic T-lymphocyte (CTL). Both B-cells and T-cells. Class I antigens called Serologically Defined (SD). Present on mast cells. H-2K, and HLA-A. Associated with beta2-microglobulin on surface. T-Suppressor cells recognize antigens with MIIC class I molecules. (Remember 1 x 8 = 8) CD8+ Class II MHC (Remember 11 x 4 = 8) CD4+

Delayed type hypersensitivity T-cells (DTII) Helper T-cell Helper inducer T-suppressor inducer cells B-cells, macrophages and activated T-cells Gene products are HLA-D Lymphocyte Defined (LD) Class II MHC genes: Are expressed on B-cells Are involved in cell-cell communication Are called lymphocyte defined or LD genes Are important in antigen presentation

C5a - Most chemotactic molecule (not C5b, C3a, C3b, C1q) C5a and LTB4 - Directly chemotactic for neutrophils (NOT LPS, NOT 1L-2). Neutrophils accumulate at inflammatory sites. Spleen - Contains antigen processing macrophages, Is a secondary lymphoid organ Is a site of antibody formation. Opsonization Pathway to effective opsonization include: Alternative complement pathway activation of C3.

IgG-antigen complexes alone (not IgM-Ag alone). Classical pathway activation of C3. Opsonins - IgG1, IgG3, C3b, (NOT C8) Congenital deficiency of the following complement components results in patient with recurrent meningococcal infections C8 and C5 (not C1-1NH, nor C2) Activators of alternative complement pathway Most bacteria, Yeast cells, Rabbi rbcs E. Coli Virus infected cells. (NOT normal lymphocytes, NOT Sheep RBC) Overall

Macrophages release IL-1 excites T-cells release IL-2 which increases Cytotoxic T-lymphocytes, Natural killer cells, BCGF (B-cells growth factor), and T-cells.

Activation of classical pathway is more specific than alternate. Antigen binding site Binds to one epitope, Has idiotypic determinants. (NOT isotypic, NOT a hypervariable or constant regions.) MHC complex Involved in graft rejection Cell communication Host defense. Anaphylatoxins C#a, C4a, and C5a (not C9a, Ba, C6a, C2a nor C1q) Complement activators Ag-IgG1 complexes Ag-IgM complexes Bacterial endotoxin Fungal cell walls (not neutrophil surfaces) Participate in B-cell activation BCGF, Antigen, IL-2 Antigen-specific helper factors

IL-1: Is produced by macrophages Is a genetically unrestricted and an immunologically nonspecific factor,

Is a polypeptide cytokine and is stable at temperatures (-750C to +560C) and pH (3 to 11). Known as LAF (lymphocyte activating factor), Excites T-cells for IL-2 production, reaction to injury and other purposes. Induces differentiation of T-lymphocytes by increasing metabolism. (Not only effects T-lymphocytes) (NOT MHC restricted NOT heat labile at high temp.)

IL-2: Its major activity is it induces T-cell proliferation, Excites CTLs Excites BCGF, BCDF secretion and activates NK (natural killer) cells. An immunologically non-specific T-cell growth factor.

Magnitude of T-cell clonal expansion depends on concentration of IL-2, IL-2 receptor density, and affinity of receptor for IL-2.

(Unstimulated T-cells do NOT express IL-2 receptors.) (does NOT act on its own secreting cell.) Normal regulation of an immune response, the following events may occur to dampen the response: Induction of anti-idiotype antibodies

Production of high affinity IgG antibody to remove antigen from the system.

Neutrophils have receptors for: IgG, C5a, and C3b (opsonins) Metabolic stimulation of neutrophils includes: H2O2 production, Incr. Glycolysis, Incr. Oxygen consumption., Decreased phagolysosomal pH (Not incr.. enzyme synthesis) TdT+: Marker on pre-B and immature T-cells Least mature T-cell. Helper cells required for the activation of the following effector cells: DTH and CTL (not macrophages and NK) Suppressor cells are CD8+ T8+ Ltl 23+ CD3+ Involved in regulation of B-cell response, Regulate DTH and CTL responses Decreased in patients with autoimmune disorders, but not absent.

Produce swelling (inject subcutaneously) C3a, C2 kinin, C5a (NOT c3b) Properdin In alternate complement pathway, stabilized C3Bb. The following could show an anamnestic response B-cell DTHT-cell (not K-cell nor macrophage) Specific immune response

To occur it is not necessary for T and B-cells to recognize determinants of antigens.

CD4+: Helper inducer, Suppressor inducer, Helper cells, TDTH cells

In normal person, the number of CD4 lymphocytes is twice the number of CD8 lymphocytes (ratio of 2:1) (NOT suppressor effector, not TCTL) (Not suppressor)

DTH (delayed type hypersensitivity) T-cell: Is antigen specific Releases lymphokines when activated Response in positive skin test indicates a CMI response occurred (NOT a helper cell for B-cell response.)

Mediators involved are: MIF, MAF,MCF and CD4+ cells (NOT CD8+ cells and NOT C-reactive protein.)

The effectors of protective cell-mediated immunity are CTL (cytotoxic T-lymphocytes), DTH (delayed type hypersensitivity T-cells), (NOT neutrophils, nor B-cells) Tc cells - Do NOT recognize antigens with MHC class II molecules. CTL - Cytotoxic T-Lymphocytes CD8+ CD3+

Lyt1-23+ CD2+

CMI against viral infection Express CD8 and specific TcR/CD3 complex, Recognize viral antigen with self MHC class I molecules. TI antigens - (T-Independent) Are often polyclonal B cell activators. Excite B-cell to produce mainly IgM antibodies, and have little or no anamnestic (secondary) response to second stimulation.

TD antigens (T-Dependent) Can be IgE and IgA antibody-eliciting antigens. Excite B-cells to make IgM antibody.

Generates anamnestic response to second stimulation (because antibody switches to making IgG)

Antibody response, both T and B-cells have antigen specificity. (Cell-cell contract is NOT essential). A T-cell mediated Immune reaction can result in Granuloma formation, A DTH reaction, Graft-versus-host disease, Tumor cell destruction. T-cell receptor complex Recognized by anti-T3 (CD3) antibodies; the following cells express T3 antigens: Cytotoxic T-lymphocytes, Suppressor cells, Helper cells (not T-stem cells) The effects of IL-2 on a precursor CTL that has not yet seen antigen in the context of MHC: NONE, since IL-2 receptors do not appear until after specific stimulation. Altered-self means The self-cell is altered (not the MHC antigens) Myeloperoxidase deficient patients can still produce H2O2 O2, and O1I. Marcophages Present antigen to the helper T-cell. Phagocytose and kill some pathogens. Remove immune complexes from the circulation. Release II,-12 Important host defense mechanism because: Process antigen and present antigen with MHC Class II (1a) molecule. Produce cytokines, and an immune response. Have nonspecific effector functions for specific DTH (NOT CTL).

Have important role as APC (antigen presenting cell). Survive after phagocytosis (Neutrophils do NOT). Activated Macrophages Have enhanced phagocytic activity. Increased intracellular microbicidal activity. Increased release of toxic produts (e.g., TNF). Increased size and lysosomal content. Macrophages Are involved in: Presenting antigen to B and T cells Induration seen in DTH skin test, (NOT involved in immediate wheel/flare skin test type I hypersensitivity)

Are the major cell type used as host cells by: amastigotes of cutaneous leishmaniasis.

Adaptive immunity Atopic allergy Anamnestic response Immunoglobulins Specific antibodies, DTH (NOT interferons, NOT complement) Innate Resistance Comp;e,emt Monocytes Macrophages Natural killer cells C-reactive protein (NOT natural antibodies, Not DTH) Mature B-cell When it can respond to immunogen by making antibody IgD and other immunoglobulins (IgM), expressed on its surface (Not when gene rearrangement of chain or express dId) B-lymphocytes- Development begins in fetal liver, Surface IgM, IgG, IgA (NOT increased with MHC molecules nor IFN) To determine if B-lymphocytes are functionally active the following tests should be performed Serum immunoglobulin levels. Serum protein electrophoresis (NOT natural killer cell assays

not mitogen assays with PHA) To determine if T-lymphocytes are functionally active the following tests should be performed Skin test for delayed type hypersensitivity.

(NOT NK cell assay, nor assays for complement components, nor serum immunoglobulin levels.)

The following systems of antigenic specificities would be useful in paternity testing Allotypes HLA antigens Blood group antigens (Not isotypes) 90% of the small cortical thymocytes DIE

(so Not express T cell receptors, nor go to the Thymic medulla, nor go into circulation.)

B cell primarily reside in The primary follicles of the lymph node.

(NOT the cortex of the thymus, not deep cortical zones of the lymph node, not follicles of red pulp of spleen.)

Antigen driven activation of B cells Usually requires interaction of macrophages, B cells, T cells and antigen. Leads to clonal expansion.

Occurs in the secondary lymphoid organs (NOT primary lymphoid organs).

In the presence of antigen A mature B cell can be activated An immature B cell may become tolerant.

A pre B cell will NOT undergo gene rearrangements to form the appropriate Ab.

A plasma cell will NOT be stimulated to divide. B cell stimulated with DNP-BSA can cooperate with T-cell stimulated with ovalbumin to produce an anti-DNP antibody response to DNP ovalbumin In a 51Cr release assay, tumor cells release their 51Cr because they have been killed by a cytolytic effector cell.. Lymphokines on the cells involved in an immune response

IL-1 IL-2 (gamma) IFN

Interferons Are anti-viral substances Augment NK activity, CTL and macrophage cytotoxicity. IFN- is most species specific, and is heat and acid Labile lymphokine. Are produced by leukocytes or fibroblasts

(Not susceptible to low or high dose tolerance, not induced by anti-idiotype or anti-allotype antibodies.)

TNF (Tumor nercrosis factor) Macrophages - - - - - produce TNF- = cachectin. Lymphocytes TNF- = Lymphotoxin/

Lymphokine Excites IL-1 production from macrophages. Excites fibroblast proliferation. Primary lymphoid organs Bone Marrow Thymus Secondary lymphoid organs Spleen [B-cells mainly in white pulp / follicle (not medulla / red pulp)] Lymph Nodes. Thymus

Cortex is mostly immature lymphocytes, therefore cells with TdT and CD1+

Monoclonal Antibodies: produced by fusing the following cells Immune spleen cells and myeloma cells (HPGRT negative) (Not normal spleen cells and myeloma cells (HGPRT positive)] Cyclosporin A Biological response modifier useful in heart, kidney, and bone marrow Transplantation. Inhibits T helper cell function. Prevents IL-2 synthesis Factors that influence tolerance induction Low or high dose antigen (vs. optimum dose antigen). Route of antigen administration. (Not amount of IL-2 secreted nor expression of Class I molecules) Preventing the activation of Immune responses to autoantigens, the following mechanisms may occur Clonal abortion, Activation of specific suppressor T-lymphocytes. (Not induction of IFN, nor production of T helper cells.)

BCDF - (B-cell differentiating factor) Is a lymphokine produced by T-cells, Is a non-specific-MHC unrestricted lymphokine that induces proliferating B cells to differentiate.

(Not a protein induced in macrophages by IL-1, not a glycoprotein on the surface of B-cells)

Important in innate resistance Macrophages, NK cells, Lysozyme, CRP. In Humoral immune response The anamnestic Ab response requires CD4+ helper T cells

T-dependent (TD) antigen fails to stimulate antibody production in nude mice. T-independent (T1) antigen stimulates B cells to produce predominantly IgM antibody. TI antigen stimulates Ab production in nude mice

Host defense against mycobacterial infection is primarily due to DTH response (Not CTL, enhanced NK, nor Ab response) Cytokines produced by T-DTH cells include: (gamma) IFN, MIF, MCF, (not TNF, NOT IL-1) Have role in B-cell differentiation. IL-4, IL-5, and IL-6. TdT is present on Pre-B and pre- T cells (not on immature B cells, nor medullary thymocytes) The idiotype of the surface immunoglobulin present on an early B-cell Is reflected in the antigen binding site Does NOT change when these cells are activated Is the idiotype of secreted IgM (changes NOT only when the DNA rearranges to allow isotype switching) Tumor cell or virus infected target cell lysis by specific cytotoxic T lymphocytes requires: Cell-cell contact and specific recognition by T-cell receptor / T3

complex of CTL. No antibody.

Divalent cations Mg 2+ and Ca2+ (Not complement) Some antibodies against tumor target cells may block CTL killing of target cells, but may help K cells to kill target. Helper T-cells respond to: IL-2, IL-1, Antigen in context of Ia, (Not hapten) NK cells Are distinct from classical T and B cells. Increased by IFN and IL-2 Are primarily LGL. Are induced by tumor cells. Have a degree of specificity more than macrophages but less than T. cells.

(do Not require natural antibodies to kill target cells.) (NOT induced by natural antigens.) (NOT restricted by class I or II molecules) (Are NOT thymus derived cells.)

IFN - (Interferon) Increase NK activity, therefore used in immunotherapies, Have anti-proliferation activity against tumor cells, Immunoregulatory activities. (NOT lymphokines) Cytotoxic lymphocytes (CTL) Recognize class I MHC Have surface markers: CD2, CD3, and CD8 (not CD4) ADCC - Mediated by: K cells (by expressing receptors for the Fe portions of IgG) NK cells,

Macrophages. (NOT B-cells) Avidity - Measure how strong a polyclonal or monoclonal antibody binds to a

complex antigen. Affinity Measures strength of binding, equal to the same determinant of different

complex negatives Probably weaker to cross-reactive epitope or avidity. Codominant expression Products of both alleles are expressed on all positive cells. Magnitude of T-cell clonal expansion is dependent upon

IL-2 concentration, IL-2 receptor density, The duration of IL-2, IL-2 receptor interaction, Affinity of the receptor for IL-2. Cyclosporin A Inhibits helper T-cells. Prevents IL-2 synthesis

(Not a potent suppressor T-cell activator, not inhibit B-cells) Non-immune early response to viral infections involve: Interferons, Natural killer cells, Complement, (Not cytotoxic T-lymphocytes) Hybridoma technology produces Monoclonal antibodies which Can cross react with tow different antigens Can be made without having a pure antigen. Important as a research tool, and has application for clinical medicine,

(Not Increased specificity following absorption with cross-reacting antigens).

Western Blot Used to confirm HIV antibodies. Known HIV antigens separated using electrophoresis. Goal is to confirm a positive ELISA. Positive bands when antibodies from patient serum binds to HIV antigens. T cell Receptors Both alpha and beta chains, have variable and constant domains. Recognize antigen in the context of MHC class I or classes II. (MHC Class II or la antigen do NOT fix complement)

(CTL doesnt recognize and kill specific virus-infection target cells because CTL recognize mainly virus antigens in the context of MHC class II antigen.)

It is easier to induce tolerance in neonates than adults. Felton demonstrated dose dependent tolerance. If mother had measles or measles vaccination, her baby may not respond well to the measles vaccine before 12 months of age. Suppress and immune reaction by Antigen specific suppressor cells Nonspecific suppressor cells, Monocytes, B-cell products.

B cell tolerance May occur if a single signal is received by a B cell Is easier to induce in immature B-cells than mature B-cells May be mediated by anti-idiotypic Ab. May be either low zone or high zone or high zone tolerance. Severe combined immunodeficiency (Not complement/B/T-cell immunodefic.)

is suggested by the combination of overwhelming and repeated viral, fungal, Hemophilus and Streptococcus infections.

Suppress and immune reaction by Antigen specific suppressor cells,

Nonspecific suppressor cells, Monocytes, B-cell products.

B cell tolerance-

May occur if a single signal is received by a B cell. is easier to induce in immature B-cells than mature B cells. May be mediated by anti-idlotypic Ab. May be either low zone or high zone tolerance.

Severe combined immunodeficiency(Not complement/B/T-cell immunodefic.)

Is suggested by the combination of overwhelming and repealed viral, fungal, Hemophilus and Streptococcus infections.

AIDS patients are-

Infected with HIV-1, HIV-2, or LAV. Infected with, HTLV-III. Infected with CD4+ T cell trophic retroviruses. Infect CD4+ cells, destroy T-helper cells, and decrease CMI. See polyclonal B cell activation / hypergammaglobulinemia. See depressed lymphocyte count (not normal levels) with reversed T4/T8 ratio. Lymphopenia. NOT primary immunodeficiency disease, it IS a secondary Immunodeficiency disease.

May die of pneumocystis carinii, or CMV infection. Virus could infect T helper cells, monocytes, macrophages, glial cells and any CD4+ cells.

(NOT Infected with IITLV-II retroviruses, not increase in NK cell activity) Immunodeficiency - Result of Malignancy and aging.

(NOT from vaccination and Increased intellectual activity.) Immunodominant The most immunogenic determinant of a complex antigen. Second set Graft rejection involves:

CMI. CTL, DTI IT-cells. (NOT antibody)

Antibody role In regulation of Immune response: Feedback inhibition of immune response caused by high affinity IgG

antibodies Interfering with antigen presentation. Idiotype-anti-idiotype network.

Affects immunogenicity of antigen by complexing with antigen. (Does NOT provide specific antibody to arm suppressor T cel Is.)

Immunize goat with rabbit bodies-

Will produce anti- isotype antibodies. Treat the following by Passive Immunization-

B-cell immunodeficiency (NOTT-cell ID). Rabies. (NOT autoimmunity)

A Mixed Lymphocyte Response (MLR)Measures I ILA-D differences.

Lymphocytes are dividing in response to IILA-D allele (NOT A, B, or C). mostly B cells, MHC class II (Ia antigens). (NOT measures 311-thymidine release, not called a plaque assay not used to characterize Class I MI IC Alleles)

Light chain genes-

do Not have D, diversity region gene segments but do have: V, variable region gene segments. J, Joining region gene segments. C, constant region gene segments.

Ig classes can be distinguished based on their HEAVY chains (NOT light chains). With regard to molecular weight IgG is larger than kappa chains.

IgM is larger that IgG. Secretory IgA is usually larger than serum IgA. (Feb fragments are NOT larger than IgG.)

General topography of an immunoglobulin gene has-Leader sequences, Intron sequences,

Exon sequences. In Serum Electrophoresis, y-globulins have:

The negative charge of the 5 protein fractions, A net mobility to the anode.

IgG: The primary effector functions of IgG are:

Opsonization (Not Incr. vasodilation, not binding to basophils)

The IgG gene, is composed of: One exon for each constant domain. A hinge region exon. DNA.

IgG crosses the placenta, At birth serum IgG is > IgM. When human IgG is injected into a rabbit, isotypic specificities antibodies are the predominant antibodies. The concentration of normal adult serum IgG is approximately 10 mg/ml.

(or 1000 mg/dl) The number of subclasses of human IgG is: 4 (four)

When IgG is digested with pepsin the following fragments are generated: F(ab)2 which have two antigen binding si sites fragment. (Fragments will f ix complement.)

IgG molecule:

The light and heavy chains are identical. The carbohydrate is in the constant region of heavy chains. (The hinge region does not join heavy and light chains.)

The IgG and the fragments of IgG were isolated from anti.- sheep red blood cell antiserum: Agglutination occurs if IgG and sheep red blood cells F(ab)2 and sheep red blood cells (not Fab and sheep rbc, not Fc and sheep rbc)

In a secondary antibody response IgG >IgM. IgA: Is the predominant immunoglobulin class in secretions.

Has one J chain. Two subclasses of human IgA. Secretory IgA has both SC (secretory component) and J chain. Secretory IgA present in tears, but NOT present in serum. Does NOT cross the placenta. (Does Not fix complement by the classical pathway, does not bind to phagocytes) Protects against human shigellosis, Found in saliva.

IgM- A pentamer. Immunoglobulin class with greatest molecular weight. Is Initially produced by most B cells. (NOT produced by switching from IgA. not encoded by 12 centimorgans 5 of the centromere of chromosome 4)

Serum IgM: Has J chain Is a pentamer (Does NOT have 2 Ab combining sites per molecule, Not fix complement less efficiently than igG)

IgE- Involved in type I hypersensitivity,

Binds firmly to mast cells and triggers anaphylaxis, Plasma cells produce immunoglobulins.

Highest concentration of antigen X is found with lowest cpm. Highest concentration of radial diffusion assay is seen with highest diameter. Highest titer in a hemagglutination assay in Inst agglutinated tube: (spread out not dot)

Serum IgM and membrane IgM have different properties for the following- Size of heavy chain, Molecular weight, Number of I chains. (Not size of light chains)

Idiotypic determinants. Can induce anti.-idiotype Abs. Are found in variable regions. (Not found In constant . ) (can NOT produce anti.-allotype Abs)

Isotypic determinants- Identify classes. Are found on constant regions. Are present among gamma globulins. (NOT found on variable regions)

The product of one normal plasma cell Has two identical light chains and two identical heavy chains.

Kappa and Lambda light chains- Are encoded on chr. 2 and 22 in man. (NOT same chromosome, do not each have multiple constant regions)

Secretory component is found in secretory IgA (not serum IgA only, not secretory IgG, not IgE) In most organ specific autoimmune diseases there is a strong association between the disease an d HLA allele.

Immune response- Immunogen injected in the muscle > Immunogen taken orally. If immunogen given to a 25 yr. old > If administered to a 10 year old. Foreign immunogen > self immunogen. Particulate immunogen > soluble immunogen

In rheumatic fever, the possible mechanism for inducing the autoimmune phenomenon is-

Infection with Streptococcus group A, a bacteria similar to host antigen. To prove by Witebskys postulates that Juvenile Diabetes is an autoimmune disease, Antibodies to the pancreas must be-

Found in most affected individuals. Capable of causing the destruction of the pancreas when injected into another member of the animal model. (Not capable of Inducing anti-idiotype Abs when injected into an animal not able to Interact with MIHC molecules)

Brutons agammaglobulinemia X-Unked. Pyogenic bacterial infections. Pt. has recurrent infections with extracellular organisms. Pt. has IgG levels less than 0.5 mg/ ml (50 mg/dl). (not usually female, not unusually high T-suppressor cell counts.) (NOT intracellular, not infections from viruses)

DiGeorge Syndrome- pt. has... Failure to produce IgG In response to T-dependent antigens, causes a Decrease in the number of helper T cells. Little or no thymic tissue. Few lymphocytes (

Macrophage cell line

Cell has NO rearranged DNA detected by either probe. Autoimmune disease Target antigen Systemic lupus erytematosus- DNA Encephalomyelitis- Neural tissue Hashimotos disease- Thyroid Myasthenia gravis- Acetylcholine receptor Juvenile Diabetes- Pancreas DO NOT Suspect a primary immunodeficiency for a 65 yr. old with recurrent infections, total immunoglobulin levels are 35 mg/mi with a monoclonal spike by serum protein electrophoresis. Rh(-) woman is pregnant with her first Rh+ child-

If fetal blood enters her circulation it will initiate a primary immune response. IgM and IgG antibodies will be produced in response to Rh antigens. Second Rh+ child may have erythroblastosis fetalis if she did not prevent immunization against Rh of first child with passive immunization. (NOT since she is Rh- she has preformed anti-bodies to Rh antigens, not Ab to Rh antigens is exclusively IgG)

Antibodies against Rh isoantigens cause erythroblastosis fetalis

Since can bind to and agglutinate rbcs of an Rh baby. Since they are IgG antibodies and can cross placenta

(NOT IgM) . Type B blood

ABO blood typing, serum will agglutinate blood from a type A individual

Has anti-A antibodies in serum. Rbcs will agglutinate in the presence of an equivalent concentration of anti-B antiserum. (Agglutinates with anti-B antibodies.) NEGATIVE agglutination will look like a button of rbcs on the bottom of the tube. (Serum does not have anti-B anti bodies in it.)

Type AB blood-

Has NO antibodies to ABO blood. Will agglutinate if incubated with anti-A or anti-fl antiserum, since it has both A and B antigens.

Hapten- Can be immunogenic if attached to a carrier molecule,

Small DNP Epitope and an antigen (but N01 an immunogen/ mitogen) (Not LPS)

Monoclonal Antibody binds to 2 complex antigens with different avidities

This could result from the antibody binding to similar determinants on the 2 antigens. The same determinant could be present In different concentrations on the 2 antigens. This is possible. (Not result from the monoclonal Ab binding to 2 completely different determinants on the antigens.)

Need an antibody with a valence of 2 or more for

Agglutination Precipitation Hemagglutination Lattice formation

The following cells can respond to specific Antigen-

Activated 0 cell (NOT cortical thymocyte, plasma cell, nor Ia positive macrophage)

Anti-mumps titer of serum from A Is 1,520 and the anti-mumps titer of serum front B I: 2; the following are possible individual A has had mum~.

Individual A has been vaccinated against mumps. Individual B has not been exposed to mumps. Individual B has not been vaccinated against mumps.

In Laboratory, in the Pregnancy assay-

Urine was tested for the presence of Human Chorionic Gonadotropin (HcG). If no HcG was present In the urine, anti-HcG would agglutinate HcG coated latex particles. If HcG was present in urine, reactivity of antibody was removed. Results can be obtained In a matter of a few minutes. Positive if NO agglutination, because urine HcG neutralized the anti-HcG.

Lines of identity in an Ouchterlony Indicate that two antigens are similar with respect to the specificity of the

antibody in the opposing well. (Not appear in areas of antibody excess, not develop within 2 hours, not indicate that 2 antigens are identical) Determine presence of same protein in sera from 2 different sources. Trypan blue exclusion- Assay used for tissue typing (I ILA-A, B, and C) by utilizing complement

mediated lysis (stains dead cells), requires typing antisera against appropriate alleles. Used clinically. (does NOT measure cell division, NOT a difficult lest.)

C5a: An anaphylatoxin (also, C3a and C4a) Chemotactic

(NOT neutralize viruses, NOT an opsonin)

C3b: In both alternative and classical pathways of complement activation can react with other serum components to form an enzyme which cleaves C3. It is an opsonin.

(NOT an anaphylatoxin, does NOT react directly with iron)

T-cells- Thymus: Stem cells ---> T-cells, Function in cell-mediated immunity, Have membrane antigenic determinants different from B cells, Important in IgA antibody response. B Lymphocytes- Have an integral membrane Ig on their surface. Major histocompatibility class I antigens-

Polymorphic surface proteins on virtually all cells. MHC Class I -

Wide cell distribution, Contains beta 2 microglobulin Composed of 2 non-covalently linked polypeptide chains (Not of equal

molecular weight), present on most cells and almost all nucleated cells (Not just B lymphocytes).

HLA-A, HLA-B, HLA-C (Not T1a). The A locus encodes for Class I antigens, serologically defined by microcytotoxicity testing. CD8 + cytotoxic T-lymphocytes recognized antigen of MIHC I recognized by CTL effectors.

MHC Class II Antigens

Composed of 2 non covalently linked polypeptide chains ( and ). CD4 + helper T-lymphocytes recognize antigen as MHC II. On surface of antigen-presenting cells that activate helper T cells.

F(ab)2 fragments-

Result from cleavage of IgG by pepsin, Have 2 combining sites for antigen.

Fab fragment and N-terminal amino acids

Fixes complement Antigen interacts with IgE - (atopy) Causes hay fever and Prausnitz-Kustner reaction. IL-1: Fever, NOT pain. PGE2: Pain LTD4: Neutrophil activation Neutralizing antibodies-

Largely responsible for preventing influenza virus infection. Terminally-differentiated B-lymphocyte = an antibody secreting plasma cell. Amplification of host defense reactions - By activating coagulation, fibrinolytic, and bradykinin-generating paths.

cause: leukocyte recruitment, vasodilation, and increased capillary permeability, neutrophil margination and trans-endothelial migration

Abortive bacterial transduction-

DNA fragments fail to replicate within recipient cells. Type III hypersensitivity-

Antigen-antibody complexes deposit in tissue, complement binds, and inflammatory events lead to tissue damage.

Recipient with HLA Antigens HLA-A I, HLA-B, DW1, DW5 lymphocytes to stimulate a minimal mixed

lymphocyte response (MLR) with this patient must have DW1 and DW5

Antigenic drift Many times involves single nucleotide base change in a virus genome. Contributes to minor antigenic changes in hemagglutinin, and Neuraminidase of influenza viruses.

T cell maturation Rearrangement of DNA which codes for T-cell receptor.

Migration to cortex to the medulla Migration to periphery. Division in response to stimulating antigens.

Anamnestic response is faster and more specific, longer lasting and greater then primary immune response. Infection - Of a sensitive bacterial culture with a bacteriophage result in: Lysogeny, Vegetative phage reproduction (lytic cycle), Integration of phage nucleic acid within bacterial chromosome, Lysogenic conversion. Primary lymphoid organ = bone marrow Secondary lymphoid organ = Spleen

BACTERIOLOGY Gram Positive bacteria Have teichoic acids, Have muramic acid Have greater peptidoglycan than gram negative bacteria Can convert to protoplasts Gram Negative bacteria Have peptidoglycan, Have muramic acid, Have flagella, O-antigens, pili, mesosomes, Have endotoxin with outer membranes (do NOT have endospore) Staphylococcus aureus Gram + cocci, Produces coagulase,

Catalase positive Mannitol fermentation Perform a catalase test, the an accustaph test Certain strain produces an exfoliative toxin and a disease called Scaled Skin Syndrome Outbreak of Staph food poisoning from contaminated common food supply.

Strep. Pneumonia Gram + cocci, alpha-hemolytic, bile+, Optochin + (zone of inhibition) Cryptococcosis - Differential diagnosis should include TB Cryptococcus neoformans (Not acid-fat, Not cause chronic subacute mycosis Not cause mycetoma, dermatomycosis, not griseofulvin D.O.C.) Rheumatic Fever - Immune response to strep. pyogenes group A. Increase ASO titer, diagnosis. Penicillin = D.O.C., long-term, cardiac Identify: Latex Agglutination Tests- Staph aureus Strep. pyogenes group A India ink test- Positively identifies Cryptococcus neoformans If stool sample for anaerobes Clostridium difficile

Prions Diseases are confined to CNS, have prolonged incubation periods, have progressive course leading to death (Are NOT exclusively in humans) Lipopolysaccharide = an Endotoxin Endotoxin - Lipid A Causes gram (-) sepsis Fever and endotoxic shock Hypotension and anoxia of organs like heart, lung and brain Dipicolinic acid is found in bacterial endospores. Composition of cell wall determines whether a bacterial cell stains gram + or (-) M protein; there are 62 types group A strep Disease: Granuloma inguinale Donovan bodies are seen from histology of genital lesion. Bacterial division lacks mitotic process. Bacteroides Gram negative rods in anaerobic disease SOD (superoxide dismutase) In aerobic bacteria (NOT in anaerobic bacteria) SOD ( superoxide dismutase) and catalase Allows facultative bacteria to be tolerant to superoxide and H2O2. Obligate anaerobe bacterial pathogen Usually lack SOD and / or catalase. Core polysaccharide

Made of 5 sugars: Glucose, galactose, N-acetylglucosamine, heptose, and keto-deoxyo oclulonic acid.