Effect of progesterone on the in vitro response of peripheral blood mononuclear cells stimulated by Escherichia coli in mares

Abstract

Escherichia coli(E. coli) isolated from the uterus of a Thoroughbred mare with bacterial endometritis was used to evaluate the effect of progesterone (P4) on the immune response of mares. Peripheral blood mononuclear cells (PBMCs) were collected from 10 nonpregnant clinically healthy adult mares (range, 4-12 years) during diestrus, four Thoroughbreds and six Hokkaido native horses. Cell proliferation and expression of cytokine mRNA, including interferon (IFN)-γ, tumor necrosis factor (TNF)-α and interleukin (IL)-10, of PBMCs stimulated with E. coli and P4 were examined in vitro. P4 was shown to have significantly inhibited E. coli induced proliferation and expression of IFN-γ in PBMCs. These results indicate that P4 inhibits the immune response to E. coli in mares. © 2012 The Japanese Society of Veterinary Science.