Question

What is the nature of the epitope-specific receptors of T cells (TCRs)?

a) Membrane-bound molecules on their cell surfaces.
b) Soluble molecules.
c) Genetically distinct from B cell receptors.
d) Genetically distinct from B cell epitopes.

Answer 1

The nature of T-cell receptors (TCRs) is that they are membrane-bound molecules on T cell surfaces and are involved in the recognition of processed foreign epitopes presented with MHC I or MHC II molecules. TCRs interact with antigenic epitopes within MHC, while BCRs can interact with epitopes on free antigens or intact pathogens.

Step-by-step explanation:

The nature of the epitope-specific receptors of T cells (TCRs) is that they are membrane-bound molecules on the cell surfaces. T-cell receptors are involved in the recognition of processed foreign epitopes presented with MHC I or MHC II molecules. They come from the same receptor family as the antibodies IgD and IgM, but the structure of TCR is smaller and less complex than immunoglobulin molecules. TCRs can only interact with antigenic epitopes that are presented within the antigen-binding cleft of MHC I or MHC II, while BCRs can interact with epitopes on free antigens or with epitopes displayed on the surface of intact pathogens.