A two-phase model of B-cell activation.

摘要: The current paradigm of lymphocyte activation, the two-signal model, has developed from premise that recognition antigen alone is insufficient to stimulate naive B cells, as this could potentially induce autoreactive responses, and cognate T-B interaction necessary a full B-cell response. Recent evidence suggests, however, T-cell-independent activation part humoral immune response pathogens, therefore alone, or plus signals provided by cells other than T can provide all Furthermore, presence secreted IgM produced either natural antibodies CD5+ B-1 antigen-induced conventional (B-2) was shown affect kinetics magnitude IgG significantly. These data observed rapid in vivo responses seem at odds with model predicts expansion delayed until sufficient T-cell help generated. I will argue here that, an infection, initial clonal secretion occurs fashion (phase I) driven antigen, serves autocrine growth factor time. B-cell-T-cell only during phase II response, thereby initiating germinal center reaction, isotype switching memory development. Hence, provides explanation how are induced rapidly time when rare.