Heterozygous mis-sense mutations in Prkcb as a critical determinant of anti-polysaccharide antibody formation

Abstract

To identify rate-limiting steps in T cell-independent type 2 antibody production against polysaccharide antigens, we performed a genome-wide screen by immunizing several hundred pedigrees of C57BL/6 mice segregating N-ethyl-N-nitrosurea-induced mis-sense mutations. Two independent mutations, Tilcara and Untied, were isolated that semi-dominantly diminished antibody against polysaccharide but not protein antigens. Both mutations resulted from single-amino-acid substitutions within the kinase domain of protein kinase C-β (PKCβ). In Tilcara, a Ser552>Pro mutation occurred in helix G, in close proximity to a docking site for the inhibitory N-terminal pseudosubstrate domain of the enzyme, resulti..