1. TCR complex and its 8 chains’ functions
a. TCRs recognize the peptides of these proteins after being processed and presented by APCs as a complex with MHC molecules
b. The effector function of the T cells is carried out via Ag-specific direct interactions with other either pathogenic or normal cells, or via effects of the cytokines secreted by the T helper cells.
c. The TCRs are similar to the BCR, as they:
i. Have Immunoglobulin protein structure
ii. Are highly diverse in their Ag-specificity
iii. Have a unique Ag specificity in each T cell
iv. Have the variability in the V region is a result of gene rearrangement
d. However, they are different in that:
i. no somatic hypermutation, and no isotype switching occur in the T cells after priming with Ag
ii. TCRs are always cell membrane-bound
iii. Each chain has a variable (V, binding an Ag) & a constant (C) regions
e. TCR 8 chain functions
i. and chains of TCR- main part; recognition of an AG
ii. 2 chains- signal transduction
iii. CD3 receptors- transfer newly synthesized TCR to the cell surface
1. and chain
2. 2 chains