V sub(H) gene family expression in mice with the xid defect

The lock of responses to certain types of antigens could be the result of deletion of or failure to express some V sub(H) genes. Because CBA/N mice, which carry the X-linked immunodeficiency (xid) gene defect, have been shown to be unresponsive to thymus-independent polysaccharide antigens, it was of interest to examine if this unresponsiveness could be accounted for by abnormal expression of particular V sub(H) gene families. Using in situ hybridization on B cell colonies, we determined the expression of nine V sub(H) gene families in CBA/CaHN females (genotypically normal), CBA/N males (xid) and females (xid), and (CBA/N x CBA/CaHN)F sub(1) males (xid) and females (phenotypically normal). Our results indicate that V sub(H) gene family expression, including the S107 family in CBA/N males and F sub(1) males, is similar to that of CBA/CaHN and F sub(1) females with predominant expression of J558, the largest gene family, in all individuals. Interestingly, CBA/N female mice, which carry two defective X chromosomes, as a group expressed significantly reduced levels of the J558 gene family, and as individuals showed variation in which family was predominantly expressed.