Regulation of allergic reaction by aerobic Corynebacterium equi extract, CEF. I. Antigen-nonspecific suppression of reaginic antibody response in mice.

The effect of a water-soluble fraction (CEF) that was prepared from an extract of Corynebacterium equi on primary reaginic antibody formation was studied in Balb/c mice. Mice were immunized with a hapten carrier (DNP-OVA) and received intraperitoneal injections of CEF 7 and 2 days prior to, or 2 and 7 days after the immunization. PCA titers of both antihapten (DNP) and anticarrier (OVA) antibodies of IgE class were reduced significantly by the CEF treatment. Evidence was presented in adoptive transfer experiments that the number of IgE-producing cells in the CEF-treated mice was lower than that of controls. Suppression of IgG1 anti-DNP antibody formation was also achieved by the CEF treatment. Formation of IgG1 anti-OVA antibodies, however, was not suppressed significantly by the treatment. The suppressive activities of CEF were shown to be dose-dependent, but timing of CEF administration did not appear critical.