Pod 7B Chap 5 Parham Antigen Recognition By Tcells

Front 1

Describe 5 ways in which TCRs are similar to immunoglobulins

Back 1

1) overall structure to the Fab segment of Ig: antigen binding site, two variable domains & 2 constant domains
2) TCRs & IG are both generated thru somatic recombination
3) the variable region contains 3 CDRs by Valpha and 3 CDRs encoded by Vbeta, analogous to the CDRs encoded by the Vh and VL of Ig
4) diversity in the TCR repertoire and its generated int eh same way as the B-cell repertoire (combination of different gene segments, junctional diversity, combination of 2 different chains)
5) TCRs need some support on the PM: CD3 gamma, delta, epsilon, chains for stabilization and signal transduction, analogous to the IGalpha and Igbeta chains for immunoglobulin cell-surface expression and signal transduction

Front 2

Describe 5 differences between TCRs and immunoglobulins

Back 2

1) TCR has ONE antigen binding site; Ig has atleast TWO
2) TCRs are NEVER secreted
3) TCRs are generated in the Thymus, not the bone marrow
4) constant region of TCR has no effector fx; does not switch isotype
5) TCRs do not undergo somatic hypermutation

Front 3

compare organization of T-cell receptor alpha and B genes with the organization of immunoglobulin heavy chain and light chains genes

Back 3

TCRalpha = Ig light chain= V&J, no D gene segments
TCR beta= Ig heavy chain= contain V, D & J gene segments

Front 4

T cell receptors do not undergo isotype switching. Why?

Back 4

T-cells are not made in a secreted form and their constant regions do not contribute to T-cell effector functions. Other molecules secreted by T-cells are used for effector functions

Front 5

What is the role of the CD 3 proteins and the zeta chain?

Back 5

to transduce signals to the interior of the cell

Front 6

the immunological consequence of severe combines immunodeficiency disease (SCID) caused by genetic defect in either RAG-1 or RAG-2 is ?

Back 6

lack of somatic recombination in T-cell receptor loci

Front 7

Amino acid variation among MHC Class II allotypes that present antigens to CD4 T cells is concentrated where?

Back 7

where the MHC molecule contacts peptide and the TCR