The regulation of resistance to Schistosoma mansoni by a soluble alpha/beta TCR analog, produced by a cloned T cell hybridoma.

Immunity to Schistosoma mansoni is regulated by an auto-anti-idiotypic network. The T cells in this network interact through soluble regulatory factors. These studies describe a soluble suppressor-inducer factor (TsiF) derived from TCR+ suppressor-inducer clone Q37. Q37 is the fusion product of CD4+ T cells derived from S. mansoni-infected mice and TCR-, BW1100 thymoma cells. [35S]Methionine biosynthetically labeled TsiF was immunoprecipitated with mAb H57-597 (anti-pan alpha/beta TCR) and adsorbed with protein G-agarose. The eluted 72-kDa TCR analog was reduced with dithiothreitol. Components of 32 and 44 kDa were found on SDS-PAGE. These components were analogous to the alpha and beta chains of the TCR, binding antigen, or expressing V beta determinants, respectively. TsiF suppressed delayed-type hypersensitivity to S. mansoni antigens in a genetically and antigenically restricted manner. TsiF totally abrogated protective immune response against S. mansoni. These soluble TCR analogs may idiotypically regulate the resistance to S. mansoni. Q37 is an appropriate source of a suppressor TCR analog for the molecular analyses of this idiotypic regulation.