Which type of T lymphocyte is responsible for activating B cells and other T lymphocytes?

Helper T cells play a crucial role in the adaptive immune response by activating B cells and other T lymphocytes. They do this by recognizing specific antigens presented by Antigen-Presenting Cells (APCs) through Major Histocompatibility Complex (MHC) molecules. Once activated, Helper T cells secrete cytokines, which serve as signals that stimulate B cells to produce antibodies and enhance the response of cytotoxic T cells. This activation process is essential for coordinating a robust immune response, allowing the immune system to effectively target and eliminate pathogens.

In contrast, suppressor T cells (also known as regulatory T cells) primarily function to downregulate immune responses and maintain immune homeostasis, thereby limiting the activity of other immune cells. Memory T cells are a part of the immune memory that helps the body respond more swiftly upon subsequent exposures to the same pathogen, but they do not directly activate B cells or other T lymphocytes. Cytotoxic T cells are specialized in directly killing infected or cancerous cells, but they do not have a role in activating B cells or helper cells. Thus, Helper T cells are essential for orchestrating the immune response through their ability to activate other immune cells.