Serum IgG from CBA/K1Jms-lprcg/lprcg mice induces interleukin 3 in an interleukin-3-dependent cell line--possible correlation with lymphadenopathy

Abstract

Serum IgG of CBA-K1Jms-lprcg/lprcg (lprcg/lprcg) mice with spontaneous systemic lymphadenopathy supported the proliferation of an IL-3-dependent cell line, FDC-P2/185-4. The lprcg/lprcg IgG induced IL-3 synthesis in FDC-P2/185-4 cells, and cells grew by an autocrine mechanism. There was virtually no time lag between the appearance of lymphadenopathy and an increase of IL-3-inducing activity in the sera. We have previously shown that serum IgG from other autoimmune mice with lymphadenopathy, MRL/Mp-lpr/lpr(MRL/lpr) and C3H/HeJ-gld/gld(C3H/gld), also induces IL-3 synthesis and cell growth in FDC-P2/185-4 cells. Furthermore, neither F1 (lprcg/+) mice between lprcg/lprcg and CBA(-)+/+ nor those (lpr-gld) between C3H-lpr/lpr and C3H/gld showed such IL-3-inducing activity, while those (lprcg-gld) between lprcg/lprcg and C3H/gld showed activity much lower than that of their parental strains but significantly higher than that of normal CBA(-)+/+ mice. This result is consistent with the incidence and degree of lymphadenopathy in these F1 mice. Our results suggest that expression of IgG(s) with cytokine-inducing activity might be controlled by these mutant genes, lpr, gld, and lprcg, and might be related to lymphadenopathy in these mice.