31. Which of the following cell types produce and release antibodies?

Answer: C

Explanation:

Plasma B cells produce and release antibodies.

Plasma B cells are specialized cells that produce and secrete antibodies into the bloodstream, which are essential for the immune response against pathogens.

A) Helper T cells

Helper T cells do not produce antibodies; instead, they assist other immune cells by releasing cytokines that help activate B cells and cytotoxic T cells. Their role is primarily in regulating the immune response rather than directly producing antibodies.

B) Cytotoxic T cells

Cytotoxic T cells are responsible for directly killing infected or cancerous cells. They do not produce antibodies; their function is focused on cell-mediated immunity, targeting cells that display abnormal or foreign antigens.

C) Plasma B cells

Plasma B cells are the primary antibody-producing cells in the immune system. Upon activation by helper T cells, they differentiate from B cells and begin to secrete large quantities of antibodies that specifically target antigens encountered by the body.

D) Natural Killer cells

Natural Killer cells play a vital role in the innate immune response by identifying and destroying infected or tumorigenic cells. However, they do not produce antibodies, as their function is distinct from that of B cells and plasma cells.

Conclusion

Plasma B cells are the only cell type among the options provided that specifically produce and release antibodies, making them crucial for the adaptive immune response. In contrast, Helper T cells, Cytotoxic T cells, and Natural Killer cells serve different roles in immunity that do not involve antibody production, highlighting the unique function of plasma B cells in the immune system.