Mechanism of suppression of lipopolysaccharide-driven B cell differentiation by anti-mu antibodies. Evidence for a trans-acting repressor of transcription.

Bivalent anti-mu antibodies suppress LPS-driven B cell differentiation by inhibiting the coordinate activation of a family of differentiation-related genes, including those encoding the heavy, light, and J chains of IgM. We have shown that the presence of inhibitors of RNA or protein synthesis during a pulse with anti-mu can interfere with induction of suppression. We suggest that suppression is mediated by a trans-acting repressor protein with specificity for common motifs in regulatory regions of each of these genes.