Uterine secretions induce phagocytosis of Escherichia coli by neutrophils.
Phagocytosis of Escherichia coli by neutrophils was induced in the presence of uterine secretions. The phagocytosis-inducing activity of uterine secretions was not changed by heat-treatment (56 degrees C for 30 min). The phagocytosis-inducing activity of uterine secretions from rabbits treated with estradiol-17 beta was slightly higher than that from control rabbits treated with vehicle. On the other hand, administration of progesterone significantly depressed phagocytosis-inducing activity of uterine secretions, and the inhibitory effect of progesterone was not affected by estradiol-17 beta. Neutrophils pretreated with uterine secretions did not phagocytize intact bacteria; in contrast, bacteria pretreated with uterine secretions were phagocytized by intact neutrophils. The present results suggest that there are heat-stable opsonins in uterine secretions which induce phagocytosis of bacteria by neutrophils, and that estrogen slightly enhances the opsonic activity of uterine secretions but progesterone depresses it and inhibits the promoting effect of estrogen.
D000818:Animals; D004926:Escherichia coli / Q000276:immunology*; D005260:Female; D009504:Neutrophils / Q000276:immunology*; D009895:Opsonin Proteins / Q000276:immunology*; D010587:Phagocytosis; D011817:Rabbits; D014599:Uterus / Q000378:metabolism*
D009895:Opsonin Proteins