Final answer:
The similar aspects of TCR and BCR signaling are that both involve protein kinases that phosphorylate ITAMs and both activate transcription factors to change gene expression. The correct answer is (d) A & B
Step-by-step explanation:
The signaling mechanisms of T-cell receptors (TCRs) and B-cell receptors (BCRs) exhibit some parallels. Answer choice (e) A, B & C is not correct because both TCR and BCR signaling pathways do not use Igα and Igβ; it is specific to BCR signaling.
Therefore, the correct answer is (d) A & B, because both have protein kinases that phosphorylate immunoreceptor tyrosine-based activation motifs (ITAMs) and both result in transcription factors being activated to change gene expression.
TCRs are composed of α and β peptide chains that span the cytoplasmic membrane of the T cell, each contributing to the formation of the antigen-binding site.
BCRs, on the other hand, are membrane-bound forms of immunoglobulins such as IgD and IgM and can recognize diverse epitopes without the need for MHC presentation, unlike TCRs that only recognize epitopes presented by MHC molecules.
The diversity in the antigen-binding sites for both TCRs and BCRs is generated through genetic rearrangement of variable (V), diversity (D), and joining (J) gene segments. This rearrangement allows a vast repertoire of unique antigen receptors capable of recognizing an almost unlimited variety of epitopes.
Both TCRs and BCRs are involved in the immune response, where they bind to specific antigens, leading to the activation and differentiation of T and B cells, respectively. Option d.