HLAⅡ类抗原表达于抗原提呈细胞（APC）并参与将抗原肽提呈给T辅助细胞。通过B细胞上的HLAⅡ类分子的信号转送在许多情况下导致细胞增殖，也可以导致细胞凋亡，但是信号是如何转送的还不清楚。该文确定了两个独立的通过HI－A11类分子起始的途径分别导致人原始的B细胞增殖和凋亡 HLA class II antigens are expressed on antigen presenting cells (APCs) and are involved in the presentation of antigenic peptides to T helper cells. Signal transduction of HLA class II molecules on B cells leads to cell proliferation in many cases and also leads to apoptosis, but it is unclear how signals are forwarded. This paper identifies two independent pathways initiated by HI-A11 class molecules that lead to the proliferation and apoptosis of human primary B cells, respectively