How do T cells and B cells differ in function?

T cells are primarily responsible for cell-mediated immunity, while B cells are responsible for humoral (antibody-mediated) immunity.

T cells and B cells are two types of lymphocytes that play crucial roles in the immune response. They are both produced in the bone marrow, but they mature and function differently. T cells mature in the thymus, hence the name 'T' cells, while B cells mature in the bone marrow.

T cells are primarily responsible for cell-mediated immunity. This means they are involved in the direct destruction of infected cells. There are two main types of T cells: helper T cells and cytotoxic T cells. Helper T cells, also known as CD4+ T cells, coordinate the immune response by stimulating other immune cells, including B cells and cytotoxic T cells. Cytotoxic T cells, also known as CD8+ T cells, directly kill infected cells by recognising antigens presented on the surface of these cells.

On the other hand, B cells are responsible for humoral, or antibody-mediated, immunity. When a B cell encounters an antigen that matches its specific receptor, it can differentiate into a plasma cell that produces antibodies. These antibodies are proteins that can bind to the antigen and neutralise it, or mark it for destruction by other immune cells. B cells can also differentiate into memory cells, which can respond more quickly and effectively to future encounters with the same antigen.

In summary, while both T cells and B cells are crucial for the immune response, they have distinct roles. T cells are involved in cell-mediated immunity, directly attacking infected cells or coordinating the immune response. B cells, in contrast, produce antibodies that can neutralise antigens or mark them for destruction, providing humoral immunity.