Bystander CD4 + T cells: crossroads between innate and adaptive immunity

摘要: T cells are the central mediators of both humoral and cellular adaptive immune responses. Highly specific receptor-mediated clonal selection expansion assure antigen-specific immunity. In addition, encounters with cognate antigens generate immunological memory, capacity for long-term, immunity against previously encountered pathogens. However, T-cell receptor (TCR)-independent activation, termed "bystander activation", has also been found. Bystander-activated can respond rapidly secrete effector cytokines even in absence antigen stimulation. Recent studies have rehighlighted importance antigen-independent bystander activation CD4+ infection clearance autoimmune pathogenesis, suggesting existence a distinct innate-like function performed by conventional cells. this review, we discuss inflammatory that activate potential physiological roles these during infection, autoimmunity, cancer.