Some characteristics of thymus suppression of antibody production in vitro in Xenopus laevis, the South African clawed toad.

Organ cultures were used to test whether thymus suppression of antibody production by spleen cells of Xenopus laevis is antigen inducible, antigen specific, or genetically restricted when a thymus-dependent (TD) antigen, horse erythrocytes (HRBC), is injected in vivo. The capacity of mammalian thymus-independent (TI) antigens, e.g. TNP-Ficoll (TI-2) and TNP-LPS (TI-1) to induce thymus suppression of the anti-HRBC) response was also tested. Additionally, the susceptibility of TI spleen responses to thymus suppression was studied. Auto- and allogeneic thymus and spleen combinations were compared to spleen cultured alone with respect to hemagglutinin titers secreted into the culture medium. The results suggest that thymus suppression of a TD response in this species is antigen inducible. Moreover, depending on the antigen used either antigen specific or unspecific suppression will be generated. Both can function across allogeneic boundaries. Responses to TI antigens are not subject to thymus suppression.