Selective inhibition of anti-nucleoside-specific antibody production by nucleoside-ricin A conjugate.

The effect of the preincubation of peripheral blood lymphocytes, from SLE patients, with nucleoside-ricin A conjugates on spontaneous A,G,C,T antibody production was examined. Enhanced spontaneous anti-nucleoside-specific antibody (anti-A,G,C,T antibody) production by SLE B cells was selectively inhibited by pretreatment in vitro with nucleosides conjugated to the ricin A chain. The selective suppression was demonstrated by the lack of suppression of the anti-DNP response or of polyclonal IgG production by pretreatment that did suppress anti-A,G,C,T production by the lymphocytes of eight patients with SLE. Furthermore, pretreatment of B cells, but not of T cells, with nucleoside-ricin A conjugates inhibited the A,G,C,T antibody response by these B cells. Thus, (A,G,C,T)-BGG-ricin A conjugates bind directly to the nucleoside-specific B cells via their antigen receptors. This demonstration of the selective elimination of B cells might have therapeutic applications in SLE.