Question

Proliferation of Na¯ CD4 T cells requires:

I. Recognition by the TCR of a peptide presented by MHC II
II. Co-Stimulation from B7 ligands
III. Interaction between CD4 and MHC II
IV. Recognition of PAMPs by T cell

a. I only
b. I II
c. I, II, III
d. I III
e. IV only
1) I only
2) I II
3) I, II, III
4) I III
5) IV only

Answer 1

Naïve CD4 T cells require recognition by the TCR of a peptide presented by MHC II, co-stimulation from B7 ligands, and interaction between CD4 and MHC II for proliferation. Thus, the correct answer is I, II, and III.

Step-by-step explanation:

The proliferation of Naïve CD4 T cells requires several key interactions and signals. Firstly, the T cell receptor (TCR) must recognize a peptide presented by MHC II on an antigen-presenting cell (APC). Additionally, there needs to be co-stimulation, such as the interaction between B7 ligands on the APC and CD28 on the T cell. Another point of interaction is between CD4 itself and MHC II, reinforcing the specificity of the immune response. Therefore, the correct options for T cell proliferation are the recognition by the TCR of a peptide presented by MHC II, co-stimulation from B7 ligands, and interaction between CD4 and MHC II.

The recognition of pathogen-associated molecular patterns (PAMPs) by the T cell itself is not part of the activation process for T cells, as these are typically recognized by innate immune receptors, not TCRs. Hence, the answer to the student's multiple choice question is I, II, III, indicating that these three conditions are necessary for the proliferation of Naïve CD4 T cells.