Which subset of effector lymphocytes is primarily responsible for regulating antibody production?

The correct choice is TH2 lymphocytes, as they play a pivotal role in regulating antibody production, particularly through their influence on B cells. TH2 cells produce a variety of cytokines, such as IL-4, IL-5, and IL-13, which are crucial for the activation and differentiation of B cells. These cytokines stimulate B cells to undergo class switching, a process that enables them to produce different types of antibodies (immunoglobulins) tailored to respond to specific pathogens. Additionally, TH2 cells promote the growth and survival of B cells and enhance their ability to produce antibodies.

In contrast, TH1 cells are primarily involved in promoting cell-mediated immune responses, particularly against intracellular pathogens, and do not directly regulate antibody production. TC (cytotoxic T cells) are specialized in killing virus-infected cells and tumor cells, playing a more direct role in cytotoxic immunity rather than influencing antibody production. Treg (regulatory T cells), while important for maintaining immune tolerance and regulating immune responses, focus on suppressing excessive immune activity rather than directly enhancing antibody production.