DELAYED-HYPERSENSITIVITY TO TRYPANOSOMA-CRUZI IN MICE - SPECIFIC SUPPRESSOR CELLS IN CHRONIC INFECTION

  • 1 January 1981
    • journal article
    • research article
    • Vol. 44  (2) , 409-417
Abstract
In mice chronically infected with T. cruzi there are antigen-specific suppressor cells which inhibit the development of delayed hypersensitivity (DTH) to T. cruzi antigen but not to an unrelated antigen, keyhole limpet hemocyanin (KLH). This was shown by comparing the 24 h footpad reactiviiy, elicited by injection of soluble T. cruzi antigen, of infected mice with that of mice immunized with killed T. cruzi antigen after pretreatment with cyclophosphamide. In the latter, 24 h footpad swelling represented a DTH reaction in that the cellular infiltrate was predominantly mononuclear and the reactivity could be transferred to normal recipients by lymphoid cells but not by serum. Chronically-infected mice developed 24 h footpad swelling but the fact that this was undiminished from an earlier 3 h reaction and could not be transfered to normal recipients by either local or systemic injection of cells, as well as the histological features, all implied that it represented a prolonged Arthus reaction. The absence or minimal levels of specific DTH detectable in chronic T. cruzi-infected mice was accompanied by the presence in their spleens of cells which specifically suppressed the generation of DTH to T. cruzi in normal mice. Suppressor cell activity was radioresistant (10 Gy/1000 rad) and T-cell mediated as defined by significantly decreased and increased suppression following anti-Thy 1.2 serum treatment and nylon wool fractionation, respectively. The ability of chronic T. cruzi mice to develop DTH to an unrelated antigen KLH was unimpaired.