1.
allele: one of two genes present at a specific locus
2.
beta 2 microglobulin: the invariant chain of the class I MHC cell surface protein
3.
CD4+ T cells: T cells whose role is cytokine secretion
4.
CD8+ T cells: T cells whose role is cytotoxicity
5.
class I MHC (major histocompatibility complex): proteins present on all nucleated cells- antigenic fragments are displayed on the target cell surface within the protein groove
6.
class I MHC restriction: refers to the fact that the antigen receptors on CD8+ T cells can only recognize antigenic fragments displayed in the groove of class I MHC proteins
7.
class II MHC (major histocompatibility complex): "proteins present on all APC; antigenic fragments are displayed within their groove, complex on cell surface"
8.
class II MHC restriction: refers to the fact that the antigen receptors on CD4+ T cells can only recognize antigenic fragments when displayed with class II MHC on the surface of an antigen presenting cells
9.
codominant expression: both alleles are expressed
10.
costimulatory molecules: molecules that are required for activation of some cells
11.
endosome: a vacuole that is formed within the cytosol
12.
human leukocyte antigens (HLA): in humans the MHC proteins may also be referred to as HLA proteins
13.
invariant chain (Ii): "a protein that is the same in all cells, blocks the class II MHC antigen binding site in the endoplasmic reticulum"
14.
polymorphism: the occurrence of different forms of particular MHC proteins within a population
15.
professional antigen presenting cell: cells whose primary role is to present antigen to T cells
16.
proteasome: a complex of proteolytic enzymes that degrade cytosolic proteins to which ubiquitin has been attached proteins
17.
transporter of antigen processing (TAP): proteins to which peptides that have been degraded by the proteasome bind to enter the endoplasmic reticulum
