Which of the following plays a role in both humoral and cell-mediated immunity? 
 

T helper cells, a type of lymphocyte, play pivotal roles in both humoral and cell-mediated immunity. In humoral immunity, they stimulate B cells to differentiate into plasma cells, which produce antibodies targeting pathogens. In cell-mediated immunity, they activate cytotoxic T cells, which directly attack infected cells or cancer cells. Additionally, T helper cells assist in activating macrophages to enhance their phagocytic activity. This dual functionality underscores the importance of T helper cells as central orchestrators of the immune response, facilitating the elimination of pathogens and providing long-lasting immunity against future encounters.