Which type of defense involves T cells?

The correct answer is cell-mediated specific defense, as this is the primary type of immune response that involves T cells. T cells, which are a type of lymphocyte, play a crucial role in the immune system by directly attacking infected cells and coordinating the immune response. They are particularly effective against intracellular pathogens like viruses and certain bacteria, as well as in tumor surveillance.

In cell-mediated immunity, T cells recognize specific antigens presented by antigen-presenting cells and become activated. This activation leads to the proliferation of T cells, differentiation into cytotoxic T cells that can kill infected cells, and helper T cells that assist in regulating other immune responses.

Other types of immune responses, such as the general immune response, antibody-mediated response, and humoral immunity, do involve other immune cells and mechanisms, but they do not primarily focus on the action of T cells. For instance, humoral immunity primarily involves B cells and the production of antibodies to neutralize pathogens, rather than the direct attack and regulation that T cells provide in cell-mediated immunity. Thus, recognizing the specific role of T cells in the immune system helps to clarify why cell-mediated specific defense is the correct choice.