Which type of immunity is mediated by B cells and the antibodies they secrete?

• A. Humoral immunity
• B. Cell-mediated immunity
• C. Passive immunity
• D. Innate immunity

Answer: (A)

Verified step by step guidance

1. Begin by understanding the different types of immunity: Humoral immunity, Cell-mediated immunity, Passive immunity, and Innate immunity.
2. Humoral immunity is primarily mediated by B cells. B cells are a type of white blood cell that produce antibodies, which are proteins that specifically target and neutralize foreign invaders like bacteria and viruses.
3. Cell-mediated immunity involves T cells, another type of white blood cell, which do not produce antibodies but instead directly attack infected cells or coordinate other parts of the immune system.
4. Passive immunity refers to the temporary immunity gained from receiving antibodies from another source, such as through breast milk or antibody injections, rather than producing them through one's own immune system.
5. Innate immunity is the body's first line of defense, consisting of physical barriers like skin and mucous membranes, as well as immune cells that respond quickly to a wide range of pathogens without the need for prior exposure.