Submitted to: Journal of Reproductive Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2005
Publication Date: 9/15/2005
Citation: Wulster-Radcliffe, M.C., Seals, R.C., Lewis, G.S. 2005. Uterine Response to Multiple Inoculations with Arcanobacterium pyogenes and Escherichia coli in Nulliparous Ewes. American Journal of Reproductive Immunology. 54:249-261. Interpretive Summary: Uterine contamination with bacteria and uterine infections postpartum reduce reproductive efficiency. Stimulating the immune system to produce antibodies against bacteria commonly associated with uterine infections may reduce the incidence and severity of uterine infections, and it would reduce the need for costly treatments and enhance reproductive efficiency. Nulliparous ewes that received primary and secondary intrauterine inoculations with bacteria had less severe uterine infections than did control ewes. The differences in immune functions between ewes previously exposed experimentally to intrauterine bacteria and control ewes probably explains the difference in the severity and/or clearance rate of infections in this study. Thus, the immune system probably recognized the bacteria in the uterus and mounted more rapid and effective humoral and cell-mediated responses against the bacteria, preventing or clearing the infection. Based on the data from this study with ewes and a previous study with heifers, it should be possible to develop an efficacious inoculation protocol for nulliparous sheep and cattle to reduce the incidence of postpartum uterine infections. Thus, an immunological approach for reducing the incidence and severity of uterine infections, rather than resorting to treating uterine infections after they develop, seems realistic.
Technical Abstract: Uterine infections seem more severe in nulliparous animals. Our objective was to determine whether intrauterine inoculation of nulliparous ewes with Arcanobacterium pyogenes and Escherichia coli would produce an antibody response and reduce the severity of infections. Nulliparous ewes (n = 9/treatment) received 1) 'primary intrauterine inoculation' with phosphate-buffered saline (PBS) and 'secondary intrauterine inoculation' with PBS; 2) primary PBS-secondary 75 × 10E7 cfu of A. pyogenes and 35 × 10E7 cfu of E. coli (PBS-Bacteria); 3) primary bacteria-secondary PBS; or 4) primary bacteria-secondary bacteria (Bacteria-Bacteria). Inoculations evoked an antibody response. Postmortem examinations 6 days after the second inoculation indicated that PBS-treated ewes did not develop uterine infections, but all bacteria-treated ewes did. Infections were either less severe or closer to resolution in Bacteria-Bacteria than they were in PBS-Bacteria ewes. Intrauterine inoculation of nulliparous ewes with A. pyogenes and E. coli evokes an antibody response that may help the uterus reduce the severity of infections.