IgE-binding factors from mouse T lymphocytes. II. Strain differences in the nature of IgE-binding factor

Normal spleen cells from high IgE responder, BDF₁ mice, formed IgE-potentiating factor upon incubation with mouse IgE, whereas those from low IgE responder, SJL mice, formed IgE-suppressive factor. The majority of the factors from BDF₁ spleen cells had affinity for lentil lectin; those from SJL mice lacked affinity for the lectin. BDF₁ spleen cells could be switched, however, to form IgE-suppressive factor if the cells were incubated with IgE in the presence of lipomodulin, a phospholipase inhibitory protein. In contrast, SJL spleen cells could form IgE-potentiating factor in the presence of lysolecithin, which enhances the glycosylation of Ige-binding factors. When the two strains were primed with alum-absorbed ovalbumin and their spleen cells were stimulated with homologous antigen, IgE-binding factors were detected in culture filtrates. The factors formed by BDF₁ spleen cells selectively potentiated the IgE response, however, whereas those formed by SJL spleen cells selectively suppressed the response. Analysis of the cellular mechanisms for the selective formation of IgE-potentiating factor by antigen-primed BDF₁ spleen cells revealed that antigenic stimulation of Lyt-1⁺ T cells resulted in the formation of two T cell factors, i.e., and 'inducer' of IgE-binding factor and a glycosylation-enhancing factor, and that these factors induced the selective formation of IgE-potentiating factor. In SJL spleen cells, antigenic stimulation of Lyt-1⁺ T cells resulted in the formation of an 'inducer' and a glycosylation-inhibiting factor, and those factors in turn stimulated the formation of IgE-suppressive factor. An additional difference between the two strains was found in FcγR⁺ Ly-1⁺ T cells that were the cell source of IgE-binding factors. Upon stimulation with IgE or 'inducer', BDF₁ Lyt 1⁺ cells formed IgE-potentiating factor, whereas the same subset of T cells from SJL mice formed IgE-suppressive factor. The results indicate that the genetic differences between the two strains with respect to the nature of IgE-binding factors appear to be expressed in the process of glycosylation of IgE-binding factors.