Which one of the following steps would be included in the primary response in humoral immunity?
A. Antigen binds to antibodies
B. Cytotoxic T cells bind to infected body cells and destroy them
C. Helper T cells activate cytotoxic T cells
D. A macrophage consumes a virus and displays antigens on its surface and signals helper T cells to divide.

Respuesta :

The answer is letter A.

Humoral immunity is a situation in which antigen binds to antibodies. It is also called as the anitbody-mediated beta cellularis immune system that is found in the extracellular fluids (e.g. antibodies, complement proteins, antimicrobial peptides. Humoral immunity is mediated by macromolecules and is so named because it can be found in the humours or body fluids.