INFLUENCE OF PRENATAL MATERNAL STRESS ON THE IMMUNOCOMPETENCE OF THE OFFSPRING

To evaluate the effects of prenatal maternal stress on the development of humoral immunocompetence in the offspring and on their hormonal and immunologic responses to postnatal stress, gravid Sprague-Dawley rats were exposed daily on gestational days 15-21 to prenatal environmental stress [(PES) 15 unsignaled, inescapable electric foot-shocks (0.05 mA for 0.5 s)] or prenatal psychological stress [(PPS) pregnant rats were placed in the nonelectrified section of the apparatus and allowed to see, hear, and smell a nonpregnant partner being environmentally stressed]. Pregnant controls (PC) were placed in the apparatus for 30 min. Serum corticosterone (CCS) and immunoglobulin G (IgG) levels were measured in the offspring every 7 days from birth to postnatal day (PND) 28. On PND 29-33, offspring were environmentally stressed; hormonal and immune status were determined on PND 34. Levels of IgG were reduced in PES and PPS offspring on PND 0 and in PES offspring on PND 7 and 28. These changes were unrelated to differences in CCS and did not reflect altered maternal-pup interactions or nutritional factors. Postnatal stress was immunosuppressive in PC pups but did not alter immune parameters in PPS offspring. In PES females, postnatal stress was also immunosuppressive. However, in PES males with already reduced IgG levels postnatal stress enhanced immune function. These data provide the first experimental evidence that prenatal maternal stress can alter immune parameters in the rat offspring.