1. Antibody class switching declines significantly once helper T cell function fails.

2. Compared to those of two nationalities, the helper T cell percentage and CD4/CD8 ratio of Uygur male were lower than those in Han male.

3. Before a helper T cell can trigger a response to a pathogen or parasite, it has to "feel" these molecular bits of an invader displayed on the surface of an antigen-presenting cell (APC).

4. This review summarizes theory and method-ology of prediction for helper T cell epitopes, and their application in vaccine development against parasites, and new research directions are also discussed.

5. These effects are primarily due to the loss of any helper T cell that can interact with the B lymphocyte correctly.