02 Ag Processing Presentation A (copy)

Antigen Processing

The mechanisms by which antigens are broken down and presented by antigen-presenting cells to T cells.

Class II MHC

Major Histocompatibility Complex molecules involved in presenting antigens to CD4+ T cells.

HLA

Human leukocyte antigens, which are the MHC genes in humans.

Alleles

Different forms of a gene, with many genes having multiple alleles.

Hybrid Class II MHC molecule

A heterodimer where one polypeptide chain is from the mother and the other from the father.

Antigen Presenting Cells

Cells that process and present antigens to T cells, including macrophages, B cells, and dendritic cells.

Co-dominant gene expression

Both alleles for a particular gene locus are expressed in an individual.

Exogenous Pathway

The pathway where exogenous antigens are processed and presented via Class II MHC molecules.

Polymorphic gene

A gene with multiple alleles in the population.

Peptide Binding Cleft

The region of the MHC molecule where peptides bind for presentation to T cells.

Invariant Chain

A protein that prevents peptide binding to MHC class II molecules and directs MHC class II to acidic vesicles.

CLIP

A fragment of the invariant chain that remains bound after cleavage in vesicles.

HLA-DM and HLA-DO

Proteins involved in removing CLIP from MHC class II molecules to allow antigen peptide binding.

Chimeric Vesicle

A vesicle where the invariant chain is degraded, allowing peptides to bind in the peptide binding groove of MHC class II.