FURTHER CHARACTERIZATION OF PROTECTIVE TRYPANOSOMA-CRUZI-SPECIFIC CD4(-CELL CLONES - T-HELPER TYPE-1-LIKE PHENOTYPE AND REACTIVITY WITH SHED TRYPOMASTIGOTE ANTIGENS() T)

We previously reported the isolation from immune mice of a panel of mu rine clonal T-cell lines which specifically recognize antigens express ed by the trypomastigote stage of the protozoan parasite Trypanosoma c ruzi, the causative agent of human Chagas' disease. Our analysis indic ated that distinct clones which recognize common as well as strain-spe cific antigenic determinants were represented. The immunoprotective po tential of several of these T-cell clones was demonstrated by adoptive transfer of protection to naive syngeneic recipients. Here we report that these T-cell clones are all of the T(H1) phenotype, as determined from their lymphokine secretion patterns. Significant levels of stimu latory activity for each clone were detected in trypomastigote superna tants, and the release of this activity was time and temperature depen dent. Seven of 10 T-cell clones tested responded to nitrocellulose-imm unoblotted trypomastigote proteins in the range of 90 to 47 kDa; no fe wer than six distinct epitopes residing on at least five distinct poly peptide species were recognized by this panel of clones. Two clones (2 G8 and 4B10) previously shown to protect in vivo responded to immunobl otted proteins in the range of 65 to 53 and 90 to 80 kD, respectively. Stimulatory activity for the latter clone was shown to be expressed o n the surface of trypomastigotes and to bind specifically to wheat ger m agglutinin, indicating that its target antigen is an 85-kDa trypomas tigote surface glycoprotein.