T-CELLS COMMIT SUICIDE, BUT B-CELLS ARE MURDERED

In addition to self tolerance, the immune system needs to be regulated when a response has been initiated, Recent data suggest that activate d T and B cells, as well as immature lymphocytes, are susceptible to p rogrammed cell death and that Fas:Fas ligand (Fast) interactions play an important role in this process, However, while T cells may kill the mselves via a Fas-dependent pathway, we propose that B cells undergo a ctivation-induced apoptosis independent of Fas, yet can be susceptible to T cell-mediated, Fast-induced death, Therefore, T cells can ''comm it suicide,'' but B cells are ''murdered'' during the regulation of an immune response! Further evidence is presented to support the hypothe sis that T cell and B cell apoptosis are initiated through fundamental ly different pathways.