Which of the following best describes the function of T cells in the immune response?

Explanation: Recognizing and responding to specific antigens. T cells are a type of lymphocyte that plays a central role in cell-mediated immunity. They recognize and respond to specific antigens presented by infected or abnormal cells, leading to their destruction.

Incorrect choices:

a. T cells are not responsible for the production of antibodies, but that is the role of B cells in the humoral immune response.

b. While T cells are involved in directly attacking and destroying infected cells, their main function is to recognize specific antigens rather than directly attacking pathogens.

c. Marking pathogens for destruction by phagocytes is primarily a function of antibodies and complement proteins, not T cells.

Explanation: B cells are specialized in producing antibodies against specific antigens. When B cells encounter a pathogen or foreign substance with a matching antigen, they become activated and differentiate into plasma cells. Plasma cells then secrete large amounts of antibodies, which can recognize and neutralize the pathogen.

Incorrect choices:

a. B cells do not directly attack and kill infected cells. That role is primarily performed by cytotoxic T cells during cell-mediated immunity.

c. Regulatory T cells (Tregs) are responsible for regulating the immune response to prevent excessive inflammation and maintain immune homeostasis.

d. B cells recognize antigens presented by antigen-presenting cells like macrophages, but their primary function is to produce antibodies, not to recognize antigens directly.