Polyclonal activation of murine B lymphocytes by Fc fragments. III. Characterization of the defect in the ability of the C3H/HeJ mouse to respond to Fc fragments.

Spleen cell preparations from the C3H/HeJ mouse were found to be refractory to Fc fragment-induced polyclonal activation. This defect was not a characteristic of all C3H strains, because spleen cells from the histocompatible C3Heb/FeJ strain produced polyclonal antibody in the presence of Fc fragments. The cellular defect was found to be associated with the macrophage population. Macrophages from C3H/HeJ mice were incapable of generating mitogenic Fc subfragments from intact Fc, whereas C3Heb/FeJ performed this function normally. That T cells and B cells from the C3H/HeJ mouse were normal was shown by the fact that C3H/HeJ spleen cells responded to Fc subfragments. Moreover, T cells from C3H/HeJ spleen cell populations could be substituted for C3Heb/FeJ-derived T cells.