Question

A T cell receptor that is positive for CD4 and CD8 is:

A. a helper and a killer T cell
B. a double negative lymphocyte
C. an immature or a tumor cell
D. a T- suppressor cell

Answer 1

A T cell expressing both CD4 and CD8 receptors indicates c)an immature or tumor cell, as mature T cells should only express one or the other, distinguishing them as either helper or cytotoxic T cells.

Step-by-step explanation:

A T cell receptor that is positive for both CD4 and CD8 is typically an indication of an immature or a tumor cell. In a normal differentiation process, T cells will mature in the thymus where they become either CD4+ or CD8+, but not both.

CD4+ T cells are known as helper T cells and are involved in activating other cells of the immune system, whereas CD8+ T cells are cytotoxic T cells that directly kill infected or cancerous cells.

The expression of both CD4 and CD8 receptors on a T cell is an indication that the cell has not fully matured or has potentially become dysregulated, as in the case with some tumor cells.