What type of lymphocyte predominates in T-cell mediated hypersensitivity reactions?

In T-cell mediated hypersensitivity reactions, T-lymphocytes are the predominant type of lymphocyte involved. These reactions are primarily orchestrated by T-helper cells, particularly the CD4+ subset, which play a crucial role in mediating the immune response.

During these hypersensitivity reactions, T-lymphocytes become activated upon recognizing specific antigens presented by antigen-presenting cells. Once activated, they can release a variety of cytokines, which further recruit and activate other immune cells, such as macrophages and other T-cells, amplifying the immune response. This type of hypersensitivity is characterized by delayed reactions, meaning that symptoms may not appear until hours or days after exposure to the antigen.

B-lymphocytes are primarily responsible for humoral immunity and the production of antibodies, while natural killer cells are part of the innate immune response. Monocytes, on the other hand, can differentiate into macrophages and play a role in the inflammatory process but are not the key players in T-cell mediated hypersensitivity reactions. Therefore, the correct answer highlights the central role of T-lymphocytes in driving these specific immune responses.