Lymphocytes III Flashcards
What T cell types are associated with the Th1 and Th2 pathways?
Helper T cells (p.196)
What is the function of cytotoxic T cells?
To kill virus infected, neoplastic, and donor graft cells by inducing apoptosis (p.197)
What is released by cytotoxic T cells?
Cytotoxic granules containing preformed proteins- perforin, granzyme, granulysin (p.197)
What is a perforin?
A preformed protein released by CD8+ T cells that helps to deliver the content of granules into a target cell (p.197)
What is a granulysin?
A preformed antimicrobial protein released by CD8+ T cells that induces apoptosis (p.197)
What is a granzyme?
A serine protease released by CD8+ T cells that activates apoptosis inside a target cell (p.197)
What is the function of regulatory T cells?
To help maintain specific immune tolerance by suppressing CD4 and CD8 T cell effector functions (p.197)
What cell surface molecules are expressed by regulatory T cells?
CD3, CD4, CD25 (a chain of IL-2 receptor) (p.197)
What cytokines are produced by activated regulatory T cells?
Anti-inflamatory cytokines- IL-10, TGF-b (p.197)
What part of the antibody structure recognizes antigen?
The variable parts of H and L chains (p.197)
What portions of the antibody structure fix complement?
The Fc portion of IgG and IgM (p.197)
What part of the antibody structure does the heavy chain contribute?
Fab and Fc portions (p.197)
What part of the antibody structure does the light chain contribute?
Fab fraction only (p.197)
What is the Fab fraction of an antibody?
The antigen binding fragment (p.197)
What chains make up the Fab fraction of an antibody?
Heavy and light chains (p.197)
What chains make up the Fc fraction of an antibody?
Heavy chains only (p.197)
What is the function of the Fab fragment of an antibody?
To determine idiotype; it is a unique antigen binding pocket with only 1 antigenic specificity expressed per B cell (p.197)
What are four features of the Fc region of an antibody?
Constant portion; contains a Carboxy terminal; Allows Complement binding at CH2 (IgM and IgG only); contains carbohydrate sidechains (p.197)
What portion of an antibody determines isotype?
Fc region (p.197)
What is antibody isotype?
IgG, IgD, etc. (p.197)
What portion of an antibody determines idiotype?
Fab region (p.197)
In what four ways is antibody diversity generated?
By random recombination of VJ (light chain) or V(D)J heavy chain genes; by somatic hypermutation (following antigen stimulation); by random recombination of heavy chains with light chains; and by the addition of nucleotides to DNA during VJ/ V(D)J recombination by terminal deoxynucleotidyl transferase (p.197)
What is the difference between VJ chains and V(D)J chains?
VJ chains are light chains; V(D)J chains are heavy chains (p.197)
To what part of the antibody do compliment and macrophages bind?
To the Fc regions of the heavy chain (p.197)
What immunoglobulins are expressed by mature B lymphocytes?
IgM and IgD (p.198)
