Influence of Y and X chromosomes on B cell responses in autoimmune prone mice

BXSB mice, unlike other autoimmune strains, carry a Y chromosome-linked gene for accelerated autoimmunity, reflected by early onset disease in male but not female animals. To investigate whether the Y chromosome factor acts through other autosomal genes or is in itself sufficient for early disease, partially inbred congenic NZB.BXSB and NZW.BXSB mice were developed and studied for levels of Ig-secreting cells (IgFC) as a measure of their autoimmune state. In such mice, the BXSB contributed only the male chromosome and 3% of the autosomal genes. The results indicate that for full expression of autoimmunity, both the Y chromosome and one or more BXSB autosomal genes are required. In addition, the presence of the CBA/N xid gene results in a total reversal of any Y-linked effects.