The Occurrence of Plaque Forming Cells in Normal and Immunized Conventional and Germfree Mice ∗

Abstract

Summary

The level of normal PFC to SRC and the immune response to 4 × 10⁸ SRC was determined in germfree mice and compared to that of CFW conventional mice. All three strains of germfree mice had normal PFC in the spleen but the CFW mice had fewer than either the Balb/c or ICR mice. The normal PFC in germfree CFW mice was approximately one half the level determined in conventional CFW mice. There was however no correlation between the level of normal PFC and the immune response to SRC. The direct and indirect technique for detecting cells producing antibody to SRC demonstrated no difference in the immune response of germfree and conventional mice. The number of PFC detected by the direct technique on any day after the injection of SRC was slightly lower in the germfree mice but otherwise the kinetics of the immune response were the same as those observed in conventional mice. The indirect technique demonstrates that the PFC synthesizing antibody other than IgM may occur sooner in germfree but otherwise is similar to that of the conventional mice. Antibody titers in the serum of CFW mice were determined with and without treatment with BME and the titers agree with the results of the PFC assays.