Autoantibody levels were significantly higher in sera from female, as compared to male SJL/J mice with pristane-induced lupus. (A) Sixteen weeks post-pristane injection, female mice (n=9) produced more serum IgG ANA than male mice (n=13), p=0.0002. (B) Female mice (n=29) produced more serum anti-dsDNA IgG Ab than male mice (n=31), p=0.03. (C and D) Female mice (n=10) produced more serum anti-dsDNA IgG1 and IgG2a Ab than male mice (n=13), p=0.024 and p=0.039, respectively. Autoantibody levels were determined using a reference-positive standard of pooled serum and expressed as attributed units per milliliter. Histograms show means and SEM for mice in each group. *p<0.05; ***p<0.0005. ANA and anti-dsDNA data are representative of two independent experiments on different sets of mice.