Responses to T-cell and B-cell mitogens in autoimmune Palmerston North and NZB/NZW mice.

Palmerston North (PN) mice, a newly recognized model of systemic lupus erythematosus, were compared with autoimmune hybrid NZB/NZW mice in a study designed to examine spleen cell responsiveness to T-cell and B-cell mitogens. Modest reductions of responses to phytohemagglutinin (PHA) and concanavalin A (Con A) were noted in PN females after 24 weeks of age; these responses were reduced significantly in NZB/NZW females. In contrast, male PN and NZB/NZW mice responded actively to PHA and Con A throughout the first year of life. Responses to lipopolysaccharide were not affected by age or sex. Anti-DNA antibody levels, blood urea nitrogen, and glomerular histology were analyzed to determine if autoantibody production or renal failure correlated with suppressed mitogenic responsiveness. These factors, examined singly and together, were not as important as age. In this system, age and sex did not influence spleen cell responses to mitogens in normal CD-1 mice. Age and sex were of minimal importance in determining responses to T-cell mitogens in the recently defined PN model of autoimmunity. In contrast, age and sex exerted strong influences upon responses to PHA and Con A in the NZB/NZW model of lupus.