Suppressor mechanisms in tumor immunity

Abstract

There are many parallels between T cell-mediated suppression of tumor immunity and suppression of immune responses to haptens and polypeptides. We propose a cell interaction model which takes this into account and outlines a regulatory pathway for suppression of immunity to tumor antigens. Free antigen or antigen/antibody complexes trigger an inducer T cell subset, Tsⁱ, which is tumor-specific. This cell activates a non-immune T cell population, pre Ts³, to generate effector suppressor cells, Ts^e. The Ts^e are specific for either the idiotype of Tsⁱ or for antigen complexed with a soluble factor made by the Tsⁱ, but the suppression they mediate is antigenically nonspecific. Tumor antigen-specific suppressor factors, TsF, play a major role in the communication between different suppressor cells. Characterization of polyclonal and monoclonal factors produced by Tsⁱ, called TsFⁱ, indicates that they both bind to tumor antigen and contain tumor-specific (idiotypic?) determinants.