118k views
0 votes
Cd₄⁺ T cells are activated by?

1) complement
2) cytokines released by dendritic cells
3) interaction between TCRs and MHC II
4) interaction between Cd₄⁺ and MHC II
5) cytokines released by B cells

User Avelino
by
8.9k points

1 Answer

3 votes

Final answer:

CD4+ T cells are activated by the interaction between their T-cell receptors (TCRs) and MHC II molecules on antigen-presenting cells, with cytokines also playing a role in this process.

Step-by-step explanation:

Activation of CD4+ T Cells

CD4+ T cells, commonly known as helper T cells, are primarily activated by the interaction between their T-cell receptors (TCRs) and antigen-presenting cells (APCs) displaying peptides on major histocompatibility complex class II (MHC II) molecules. Upon encountering an APC, the CD4+ T cell's TCR binds to the MHC II molecule that is presenting an antigenic peptide. This binding is necessary for the activation of the naive helper T cell. In addition to this interaction, the activation process involves both the APC and the T cell releasing cytokines, which are signaling molecules that aid in the proliferation and differentiation of T cells.

The direct answer to the student's question is that CD4+ T cells are activated by Option 3) interaction between TCRs and MHC II. Option 4) interaction between CD4+ and MHC II is partially correct, as the interaction of CD4+ with MHC II is part of the larger binding event involving the TCR.

User Josh Yeager
by
8.4k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.