Imm 4 - B Cells And Antibodies Flashcards
What are the 2 cytokines that the helper T cells produced in order to stimulate B cells?
IL-4. IL-5.
What are 8 surface markers that B cells have?
CD19. CD20. CD21. IgM. IgD. MHCII. B7 protein. CD40.
What two surface markers does NK Cells have?
CD56. CD16.
What is Antiboyd-dependent cell mediated cytotoxicity (ADCC)?
When NK cells bind to the constant region of immunoglobulins with the surface marker CD16 they have and kill the antibody-coated infected cells.
What 4 surface markers does macrophages have?
CD14. MHC II. B7 protein. CD40. All nucleated cells have MHC I.
What is the structure of an Antibody (Ab)?
It has 2 heavy chain regions and 2 light chain regions. At the very tip of each chain, it has hypervariable region on the amino portion. The Ab is held together by disulfide bonds. They have two different functional regions: the Fab region and Fc region.
What does the Fab region of an Ab do?
It is the Antigen binding fragment (which includes the variable region on the amino terminal end of the Ab) it is what determines the idiotype (the unique antigen) to which that Ab can combine.
What does the Fc region of an Ab do?
The constant region, found in the carboxyl terminal of the Ab, and only includes the heavy chains. This is the only region of the Ab that can bind to complements. This is the portion of the Ab that is recognized by the CD16 on NK cells. It is the region that determines the Isotype of the Ab (whether its IgG or IgM or IgA).
Which portion of the Ab determines the idiotype? The Isotype?
The idiotype is determined by the Fab region. The isotype is determined by the Fc region.
What are the five different types of heavy chains that determine the isotype of an Ab?
Mu (IgM). Delta (IgD). Gamma (IgG). Alpha (IgA). Epsilon (IgE).
What are the two different types of light chains in an Ab?
Lambda. Kappa. No functional difference b/w the two.
What is the normal ratio of kappa to lambda light chains in Ab?
About 2:1.
What do Antibodies do?
They bind to antigens. Can neutralize and/or opsonize pathogen. Activate complement.
What is V(D)J recombination?
Rearrangements of the DNA segments named variable (V), diversity (D), and joining (J) compose the coding region for each specific antigen receptor on B and T cells. This explains the Ab variability and the variability of antigen specificity in T cells.
Describe the process of V(D)J recombination.
The rearrangement process begins w/ breaks in the dsDNA at Recombination Signal Sequences (RSSs) that flank the V, D, and J coding regions. V(D)J recombination is initiated by the recombination activating gene complex (RAG-1 and RAG-2; these proteins recognize the RSSs).