THE DEVELOPMENT OF PERIPHERAL TNP-TOLERANCE AND SUPPRESSOR FUNCTION IN XENOPUS-LAEVIS, THE SOUTH-AFRICAN CLAWED TOAD

In adult Xenopus laevis, inducer- and effector-suppressor functions ar e located in the spleen. These peripheral suppressor functions must be established at this location near the end of metamorphosis, since bot h functions are in the thymus in premetamorphic and in developmentally -blocked metamorphosing larvae. This study examined whether TNP-conjug ated self-antigens resulting from exposure to trinitrobenzene sulfonic acid (TNBS), will stimulate TNP-tolerance in premetamorphic, metamorp hic, and in developmentally-blocked metamorphosing larvae. Premetamorp hic and developmentally-blocked larvae produce little TNP-tolerance or peripheral suppressor function. However, when TNBS exposure includes the late stages of the metamorphic period, both TNP-tolerance and sple nic anti-hapten suppressor function are demonstrable. Removal of suppr essor function with cyclophosphamide prevents expression of tolerance, thus, they are functionally related. Suppressor function and toleranc e both differentiate during the late metamorphic stages when new adult antigens are being expressed and incorporated into a library of self.