Carrier-specific suppression of antibody responses by antigen-specific glycosylation-inhibiting factors.

We previously established an ovalbumin (OA)-specific T cell clone from spleen cells of BDF1 mice, which had been treated by i.v. injections of OA, and constructed antigen-specific T cell hybridomas from the T cell clone. One of the hybridomas constitutively released glycosylation-inhibiting factor (GIF) which lacked affinity for OA, and was called non-specific GIF. Incubation of the same hybridoma cells with OA-pulsed syngeneic macrophages or OA-pulsed B lymphoblastoid cells of BALB/c origin resulted in the formation of GIF molecules that had affinity for OA but not for bovine serum albumin or keyhole limpet hemocyanin. Both the OA-specific GIF and nonspecific GIF bound to monoclonal anti-lipocortin and possessed I-Jb determinants. The OA-specific GIF consisted of two species of molecules, of m.w. 80,000 and 30,000 to 40,000, respectively, whereas the nonspecific GIF from unstimulated cells had an m.w. of 15,000. Intravenous injections of OA-specific GIF or nonspecific GIF into BDF1 mice suppressed both the IgE and IgG1 anti-hapten antibody responses of the animals to dinitrophenyl derivatives of OA (DNP-OA), but OA-specific GIF was much more effective than nonspecific GIF in suppressing the antibody responses. When the same preparations of GIF were injected into DNP-KHL-primed mice, OA-specific GIF and nonspecific GIF were comparable in suppressing the anti-DNP antibody response. In contrast to the 40,000 m.w. species of OA-specific GIF, the 80,000 m.w. OA-specific GIF had carrier-specific suppressive effects. The similarities of antigen-specific GIF to antigen-specific TsF suggest that the phospholipase-inhibiting activity of the molecules may be involved in the immunosuppressive effects of some antigen-specific TsF.