B cells on the podium: regulatory roles of surface and secreted immunoglobulins

A long-lasting prejudice in immunology pictures T cells as active regulatory subjects and B cells as passively regulated objects. In this article, Fabrizio Manca and colleagues discuss how the notion of a passive, regulated B cell is being superseded. The emerging hypothesis is that B lymphocytes not only capture, internalize, process and present antigens to T cells, they also - through their specific paratope - govern the patterns of enzymatic degradation, and thus are instrumental in selecting the particular T cell from which they gain help. B cells therefore influence the expression of both T- and B-cell repertoires.