SEX-DIFFERENCES IN PRIMARY HUMORAL RESPONSES OF ALBINO-RATS TO HUMAN SERUM-ALBUMIN

Primary humoral responses to human serum albumin, with or without concomitant Freund's adjuvant, were determined for over 300 male and female Wistar albino rats. Groups of female rats always displayed significantly more antibody production than males. Without adjuvant only 70% of the males responded compared to 99% of the females. When the antigen was accompanied by adjuvant, more than 95% of both sexes responded. Whereas without adjuvant the female response was only twice that of the males, adjuvant facilitated the response to a factor of 10 greater than the males. Both the gender and adjuvant effect each accounted for about 16% of the variance in the measurements of antigen binding capacity. Post-weaning castration did not simulate the gender differences; there were no group differences in ABC at the extremes of estrus-related ambulatory cycles.