The immune system of geriatric mice is modulated by estrogenic endocrine disruptors (diethylstilbestrol, alpha-zearalanol, and genistein): effects on interferon-gamma.

The immune system is a potential target for estrogenic endocrine disrupters. To date, there is limited information on whether estrogenic endocrine disruptors modulate the immune system of aged individuals. To address this issue, groups of 74-week-old mice were given nine oral doses of selected estrogenic endocrine disrupters: diethylstilbestrol (DES, 3 microg/100 g bw), alpha-zearalanol (0.5 mg/100 g bw), or genistein (0.15 mg/100 g bw) in corn oil, or corn oil alone, over 2.5 weeks. Both developmental (thymus) and mature (spleen) lymphoid organs were affected, although specific effects varied with the chemical. DES significantly decreased thymocyte numbers. However, relative percentages of thymocyte subsets were not altered. While splenic cellularity and percentages of T and B cells were unchanged, splenocytes from DES-exposed mice had significantly decreased ability to proliferate in response to Concanavalin-A (Con-A). Con-A-activated splenocytes from mice treated with genistein or alpha-zearalanol had decreased levels of interferon-gamma (IFNgamma) protein in their culture supernatants compared to similar cultures from oil-treated mice. RT-PCR analysis of Con-A-activated splenocytes revealed that the expression of IFNgamma gene is altered by DES or genistein treatment. Together, these results suggest that estrogenic endocrine disruptors modulate the immune system of aged mice.