Which of the following vaccines is recommended for healthcare workers to protect against hepatitis B?

Explanation:Innate immunity. Innate immunity is the body's first line of defense and provides immediate protection against infections without prior exposure to the pathogen. It includes physical barriers, such as the skin, and various cellular and chemical components.

Incorrect choices:

a. Adaptive immunity is the acquired immunity that develops after exposure to a specific pathogen or vaccination. It takes some time to mount a response and produce antibodies or memory cells.

b. Humoral immunity is a component of adaptive immunity that involves the production of antibodies by B cells to neutralize pathogens.

d. Cell-mediated immunity is another component of adaptive immunity, where T cells directly attack infected or abnormal cells.

Explanation: B cells are a type of lymphocyte that plays a crucial role in the immune response by recognizing and binding to specific antigens. When a B cell encounters an antigen that matches its specific receptor, it becomes activated and differentiates into plasma cells, which produce antibodies against the antigen.

Incorrect choices:

b. Cytotoxic T cells are responsible for directly attacking and killing infected or abnormal cells during cell-mediated immunity. They do not primarily recognize antigens during the immune response.

c. Macrophages are antigen-presenting cells that engulf and process pathogens to present their antigens to other immune cells, such as T cells and B cells. While they are involved in antigen recognition, they are not the primary cells responsible for this function.

d. Red blood cells do not have a direct role in antigen recognition or the immune response. Their primary function is to transport oxygen throughout the body.