Term
| Types of Binding Forces between Antigen and Antibody |
|
Definition
[image] (Strongest at the top, Weakest at the bottom) |
|
|
Term
| Specificity of Antibody Recognition of Antigen Based On: |
|
Definition
| Sequence of amino acids (primary structure) as well as secondary and tertiary structures of the antigen |
|
|
Term
| Five Isotypes of Immunoglobulin |
|
Definition
IgG IgM IgD IgA IgE Each has 2 heavy chains and 2 light chains Light chains attached to heavy chains by disulfide bonds; heavy chains attached to each other by disulfide bonds Constant regions: IgG, IgD and IgA have 3; IgM and IgE have 4 Difference in amount of glycosylation between isotypes |
|
|
Term
| Secondary and Tertiary Structure of Immunoglobulin Molecule |
|
Definition
[image] Fab= antigen binding fragment (above hinge); both arms recognize the same epitope (they are homogenous) Fc= compliment binding fragment (below hinge) CDRs= complimentarity determining regions (at least 1 CDR from both the heavy and light chains must bind to antigen--preferably more than one from each) Hinge is flexible to allow two arms to react to different sized antigens |
|
|
Term
Complimentarity Determining Regions (CDR) |
|
Definition
At least 1 CDR from both the heavy and light chains must bind to antigen--preferably more than one from each AKA hypervariable regions (HVR) As the immune system matures, antibodies bind more tightly to antigens because of gene rearrangement and mutation in HVRs CDRs are seaparated by framework regions (FR) that do not mutate as much as CDRs |
|
|
Term
| Optional Immunoglobulin Components |
|
Definition
J Chain = Joining Chain -- when immunoglobulin exists as polymer, it joins monomers in Fc region; produced by B cells or mature plasma cells along with the heavy and light chains (e.g. secretory IgA typically found as a dimer or trimer; IgM always found as a pentomer -- more monomers per polymer = better at agglutinating antigens) Secretory Component --provides protection against proteolytic digestion and aids in translocation of IgA from producing cell (B cell) to secretory fluid (into collecting duct); NOT produced in B cells or plasma cells, but rather in specialized cells called secretory epithelial cells (located in salivary glands and other mucosal sites of the body) |
|
|
Term
|
Definition
Based on amino acid sequences over entire heavy chain constant region There are five isotypes (IgG, IgA, IgE, IgM, and IgD) |
|
|
Term
|
Definition
Based on distinct small regions of amino acid sequences in heavy chain constant region There are at least 20 IgG allotypes in humans |
|
|
Term
|
Definition
| Based on distict regions of amino acid sequence in heavy and light chain variable regions |
|
|
Term
|
Definition
Based on subtle amino acid sequences over entire heavy chain constant region 4 IgG subclasses 2 IgA subclasses Other isotypes do not have subclasses |
|
|
Term
| Properties of Immunoglobulins |
|
Definition
[image] IgM is much larger because of the fact that it is a pentomer IgA is the most prevalent throughout the entire body (most found in gatrointestinal tract and repiratory tract) IgG is the most prevalent in the blood stream IgG1, IgG2, and IgG3 can cross the placenta of a pregnant woman; NO OTHER IMMUNOGLOBULINS CAN |
|
|
Term
| Immunoglobulin Isotype Distributions |
|
Definition
IgG - Blood, extracellular space and fetus IgM - Blood IgA - mucosal epithelial surfaces and breast milk IgE - epithelial surfaces (key role in type I hypersensitivity) Brain - note absence of Ig |
|
|
Term
| Effector Functions of Antibodies |
|
Definition
|
|
Term
PMN Opsonization and Phagocytosis |
|
Definition
PMN have receptors for both the Fc region of antibodies and for C3 and C3b of the complement system Abundance of FcγR on surfaces of PMN in circulation Abundance of FcαR on surfaces of PMN at mucosal surfaces PMN that enter mucosal sites from the circulation gradually lose their FcγR and gain more FcαR |
|
|
Term
|
Definition
| Some targets may be too large to be fully phagocytosed or they avoid engulfment, resulting in frustrated phagocytosis in which no phagosome is formed. These may be killed extracellularly. However, tissue damage occurs when neutrophil (or macrophage) microbicidal products are released extracellularly to such an extent that host defences (antioxidant and antiprotease screens) in the immediate vicinity are overwhelmed. |
|
|
Term
| Key Characteristics of the Anamnestic Response (Secondary or Memory Response) |
|
Definition
Faster rising antibody levels Higher antibody levels Longer-lasting antibody levels [image] The first isotype that is always induced (in every exposure to a new or recurrent antigen) is IgM followed by IgG and IgA; in the primary exposure IgM is expressed at the highest levels, while in all subsequent exposures IgG is expressed at the highest levels The higher resonse to secondary exposure is the theory behind booster shots and mult-shot immunizations The immune response to secondary exposure is much more rapid than the first -- this is the reason that you don't get chickenpox a second time; once you are exposed a second time the immune system reacts quick enough that no symptoms are seen The more times the immune system is exposed to the same antigen, the higher the antibody affinity for the antigen making the immune system more effective |
|
|
Term
| Clonal Selection Induces Large Number of Identical Responding B Cells |
|
Definition
[image] Induction of one naïve B cell results in many clones being made resulting in plasma cells and memory B cells that will produce antibodies to the antigen (Ag) This is a clonal response -- all future cells produce exactly the same antibody that respond to exactly the same angtigenic epitops |
|
|
Term
| Phases of the Humoral Immune Response |
|
Definition
|
|
Term
| Time Course of Immunoglobulin Synthesis, Bacterial Colonization and Tooth Eruption |
|
Definition
|
|
