The ratio of helper T4 cell to suppressor T cells is normally 2:1 . A lower than normal ratio may indicate acquired immunodeficiency syndrome (AIDS). This is because T4 cells:

Question

a. enhance humoral immune response.
b. suppress the humoral response.
c. suppress the cell-mediated response.
d. are a feature of an autoimmune disease.

Answer 1

A
Once contact is made with a specific antigen, the T lymphocyte differentiates into helper/inducer T cells, suppressor T cells, and cytotoxic killer cells. Although these T cells are microscopically identical, they can be distinguished by proteins present on the cell surface called cluster of differentiation (CD). Helper T cells (also known as T4 cells because they carry a CD4 marker) enhance the humoral immune response by stimulating B cells to differentiate and produce antibodies. Suppressor T cells downgrade and suppress the humoral and cell-mediated responses. The ratio of helper to suppressor T cells is normally 2:1, and an alteration in this ratio may cause disease. For example, a depressed ratio (a decrease of helper T cells in relation to suppressor T cells) is found in acquired immunodeficiency syndrome (AIDS), whereas a higher ratio (a decrease in suppressor T cells in relation to helper T cells) is a feature of an autoimmune disease.