Mechanisms of regulation of cell-mediated immunity. III. The characterization of azobenzenearsonate-specific suppressor T-cell-derived-suppressor factors.

Abstract

Delayed type hypersensitivity to the hapten azobenzenearsonate (ABA) can be induced and suppressed by the administration of hapten-coupled syngeneic spleen cells by the appropriate route. Suppressor T cells stimulated by the intravenous administration of ABA-coupled spleen cells have been shown to produce a discrete subcellular factor(s) which is capable of suppressing delayed type hypersensitivity to azobenzenearsonate in the mouse. Such suppressor factors may be produced by the mechanical disruption of suppressor cells or by placing such suppressor cells in culture for 24 h. The suppressor factor(s) (SF) derived from ABA-specific suppressor cells exhibit biological specificity for the suppression of ABA delayed type hypersensitivity (DTH), but not trinitro-phenyl DTH, as well as the capacity to bind to ABA immunoadsorbents. Passage of suppressor factor(s) over reverse immunoadsorbents utilizing a rabbit anti-mouse F(ab')2 antiserum demonstrated that the antigen-specific T-cell derived SF does not bear conventional immunoglobulin markers. The suppressor factor(s) are not immunoglobulin molecules was further demonstrated by the inability of anti-ABA antibodies to suppress ABA DTH. Gel filtration of ABA suppressor factor(s) showed that the majority of the suppressive activity was present in a fraction with molecular weight ranging between 6.8 x 10(4) and 3.3 x 10(4) daltons. We also analyzed for the presence of determinants encoded by the H-2 major histocompatibility complex (MHC) and found that immunoadsorbents prepared utilizing antisera capable of interacting with gene products of the whole or selected gene regions of H-2 MHC, i.e., B10.D2 anti-B10.A and B10 anti-B10.A immunoadsorbents, retained the suppressive activity of ABA-SF. Elution of such columns with glycine HCl buffers (pH 2.8) permitted recovery of specific suppressive activity. Taken collectively such data supports the notion that suppressor T-cell-derived ABA suppressor factors have antigen-binding specificity as well as determinants controlled by the K end of the H-2 MHC. The distribution of strains capable of making SF has also been analyzed. The relationship of the antigen-binding specificity to VH gene products is discussed in this and the companion paper.

Studies of Immune Responsiveness and Unresponsiveness to the p‐Azobenzenearsonate (ABA) Hapten

“…Takemori & Tada (1975) first demonstrated that the activity of afferent "Tsilike" suppressor cells could be mediated by the soluble protein fraction of suppressor cell lysates. Since these studies, soluble suppressor factors have been isolated in a number of systems (Yamauchi et al 1981, Kapp et al 1976, Waltenbaugh et al 1977) including the ABA system where sonicates, freeze-thaw extracts and supernatants from Tsi-containing splenocyte populations have been shown to suppress the DTH and CTL responses to ABA (Greene et al 1979a(Greene et al , 1982b. Effective suppression is only observed when the TsFi is administered beginning on or before the day of immunization, characterizing the factor, as was the cell from which it was derived, as a mediator of afferent suppressive activity.…”

“…Characterization of TsFi has revealed that it is an antigen-binding molecule whose activity can be adsorbed on ABA-but not TNP-derivatized cells (Greene et al 1979a). When generated in mice with the Igh-1^ or Igh-l** genotype, the ABA-induced TsFi bears idiotopes recognized by rabbit anti-cross-reactive idiotypic antibody (Bach et al 1979).…”

“…When generated in mice with the Igh-1^ or Igh-l** genotype, the ABA-induced TsFi bears idiotopes recognized by rabbit anti-cross-reactive idiotypic antibody (Bach et al 1979). The activity of the TsFi molecule is antigenspecific, being able to suppress the DTH response to ABA but not to TNP (Greene et al 1979a). In addition, expression of the ABA TsFi-mediated suppression does not require complete matching at the H-2 region of the recipient and the donor from which the factor was generated (Greene et al 1982a).…”

“…As discussed above, this cell is operative early in the Ts pathway, and appears to recognize and be induced by antigen. Once activated, the Tsi subsequently releases a soluble mediator, TsFi, which manifests the biological activity of intact Tsi cells (Greene et al 1979a). When induced in strains of mice able to synthesize cross-reactive idiotypic (CRI) determinants on anti-ABA antibodies, the TsFi molecules also bear similar determinants (Bach et al 1979).…”

The Biochemistry of Antigen-Specific T-Cell Factors

“…In many cases these cells have been shown to release suppressor factors that block the appearance of antibody-forming cells (18,20,34,48). Also, haptens, either on proteins or on autologous cells, may induce specifi c T s F (14,54). Cellular immune re sponses to alloantigens or tumor antigens may be shown to be regulated by suppressor cells and T s F (15,38).…”