Question

Place the events of activation of a T helper cell in order. - Helper T cell binds APC - Helper T cell proliferates - APC engulfs antigen and presents it on an MHC class II molecule - Helper T cell secretes IL-2

Answer 1

The activation of a T helper cell involves the binding of a helper T cell to an APC presenting an antigen on an MHC class II molecule, followed by the release of cytokines and proliferation of the activated helper T cell.

Step-by-step explanation:

1. An antigen-presenting cell (APC) engulfs the antigen and presents it on an MHC class II molecule.
2. A CD4+ helper T cell binds to the MHC II-antigen complex on the APC.
3. The helper T cell releases cytokines, such as IL-2, which activate the helper T cell.
4. Once activated, the helper T cell proliferates, dividing into clonal naïve helper T cells that differentiate into subtypes with different functions.