Immunology Flashcards
What is the function of macrophages?
Phagocytosis and activation of bactericidal mechanisms
Antigen presentation
What is the function of dendritic cells?
Antigen uptake in peripheral sites
Antigen presentation
What is the function of neutrophils?
Phagocytosis and activation of bactericidal mecahnisms
What is the function of eosinophils?
Killing of antibody-coated parasites
What is the function of basophils?
Promotion of allergic responses ad augmentation of anti-parasitic immunity
What is the function of mast cells?
Release of granules containing histamine and active agents
What is the ratio of the amounts of the two types of lymphocyte?
20% B cells, 80% T cells
What are epitopes?
Sub-protein specific elements
What do T-cell receptors bind to?
A complex of an antigen fragment and a self molecule, MHC
Which cells bind to MHC class 1?
CD8+ Tc cells
Which cells bind to MHC class 2?
CD4+ Th cells
What does the TCR resemble?
A membrane bound Fab fragment
What is the structure of the T cell receptor?
Membrane bound heterodimer
Under what circumstances can TCR see its cognate antigen?
When the antigen is presented to it bound to a specific MHC molecule
What is the main difference between the way MHC classes I and II bind peptides?
MHC class I are held tightly at each end whereas MHC class II extend beyond the groove
Which MHC class bind antigen peptides along their length?
MHC class II
Which MHC class bind antigen peptides at the end?
MHC class I
Do T cells express CD4 or CD8 surface proteins?
They express both, but any particular T cell only expresses one or the other
Where are the binding sites for CD4 and CD8 on MHCII and MHC respectively?
The immunoglobulin domains
What are the four main processes that allow for huge immunoglobulin diversity?
Combinatorial diversity during segment recombination
Junctional diversity during segment joining
Cominational diversity driven by different combinations of heavy and light chain
Somatic hypermutation
How are MHCI molecules transported from cytosol to the endoplasmic reticulum?
They are actively pumped across the membrane by the TAP complex
