Antigen Recognition by T cells (9)

What does the T cell receptor resemble?

Immunoglobulin

What are some characteristics of immunoglobulin/BCR?

Membrane-bound, secretion following antigen recognition, isotype switching following antigen recognition, and somatic hypermutations following antigen recognition

What are the differences in characteristics between BCR and TCR?

TCR do not have secretion, isotype switching, or somatic hypermutations following antigen recognition

What are the shared characteristics of BCR and TCR?

Membrane-bound

What makes up the T cell receptor complex?

TCRalpha-abeta or TCRgamma-delta, CD3epsilon-delta, CD3gamma-epsilon, and CD3zeta-zeta

What are the T lymphocytes (CD3) receptors?

TCRalpha-beta and TCRgamma-delta

What are the co-receptors of TCRalpha-beta?

CD4+ and CD8+

What is the CD4+ T cell?

T helper (Th)

What are the CD8+ T cell?

Cytotoxic T cell (CTL)

Role of T helper (Th)

Helps B cells, macrophages, and some other cells

Role of cytotoxic T cell (CTL)

Kill virus- and other intracellular pathogen-infected cells and tumor cells

Recognize antigens bound to MHCII

CD4 T cells

Recognize antigens bound to MHCI

CD8 T cells

Binds the alpha3 domain of MHC class 1

CD8

Binds the beta2 domain of MHC class 2

CD4

Expressed by all nucleated cells

MHC 1

What is MHC 2 expressed by?

B cells, macrophages, dendritic cells, and epithelial cells of the thymus