Which statement describes antibody-mediated immunity?

Which statement describes antibody-mediated immunity?

• A. B lymphocytes produce antibodies.
• B. T lymphocytes destroy infected cells directly.
• C. Antibody-mediated immunity requires no cellular participants.
• D. Macrophages present antigen to natural killer cells.

Answer: (A)

Antibody-mediated immunity is driven by B lymphocytes that produce antibodies. When B cells encounter their specific antigen (often with help from helper T cells), they differentiate into plasma cells that secrete antibodies into the blood and other body fluids. These antibodies bind to antigens on pathogens or toxins, neutralizing them and marking them for destruction. They can also recruit other parts of the immune system, such as promoting phagocytosis by opsonization or activating the complement system to help eliminate invaders. The other statements describe different aspects of immunity: cell-mediated immunity involves T cells that destroy infected cells directly; antibody-mediated immunity does not happen without any cellular participants, since B cells (and often helper T cells for activation) are essential; and antigen presentation typically involves macrophages presenting to T cells rather than to natural killer cells.

Antibody-mediated immunity is driven by B lymphocytes that produce antibodies. When B cells encounter their specific antigen (often with help from helper T cells), they differentiate into plasma cells that secrete antibodies into the blood and other body fluids. These antibodies bind to antigens on pathogens or toxins, neutralizing them and marking them for destruction. They can also recruit other parts of the immune system, such as promoting phagocytosis by opsonization or activating the complement system to help eliminate invaders.

The other statements describe different aspects of immunity: cell-mediated immunity involves T cells that destroy infected cells directly; antibody-mediated immunity does not happen without any cellular participants, since B cells (and often helper T cells for activation) are essential; and antigen presentation typically involves macrophages presenting to T cells rather than to natural killer cells.