Production and utilization of a mouse monoclonal antibody to rat IgA: identification of gender-related differences in the secretory immune system.

The present study was designed: to produce a mouse monoclonal antibody to rat IgA; and to examine, by using the monoclonal antibody, possible gender-related differences in the secretory immune system. Hybridomas were prepared that secreted mouse monoclonal antibodies directed specifically against rat IgA. These antibodies were identified as IgG1 and kappa chain positive and could be used to purify rat IgA by affinity chromatography, detect tissue IgA by immunofluorescence and measure IgA levels in external secretions by radioimmunoassay. In utilizing these antibodies, we found that a distinct, gender-related difference exists in the number of IgA-containing cells in the rat lacrimal gland. Lacrimal tissue from male rats had a significantly higher content of IgA-positive cells than did that from female rats. This difference correlated well with our previous observations on the sexual dimorphism in tear IgA levels. We also observed in the present study that gender-associated variations in IgA content occur in respiratory secretions. In contrast to the eye, however, females had significantly greater IgA concentrations than did males. No effect of gender was found on IgA levels in small intestinal secretions, saliva or serum. Overall, our results indicate that gender may play a role in the immune response of specific mucosal tissues.