Uterine defense mechanisms in the mare: Serum opsonins affecting phagocytosis of Streptococcus zooepidemicus by equine neutrophils

• Published in: Theriogenology Vol. 21; no. 2; pp. 375 - 385
• Main Authors: Asbury, A.C., Gorman, N.T., Foster, G.W.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.1984
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/0093-691X(84)90422-9

The addition of serum to uterine secretions was shown to opsonize Streptococcus zooepidemicus and significantly enhance bacterial phagocytosis by equine neutrophils. Treatment of serum by heat inactivation at 56°C, EDTA treatment, and C3 consumption reduced phagocytosis and therefore demonstrated that the process was complement-dependent. The amount of C3 present in uterine secretions was measured in a series of 14 mares infected with Streptococcus zooepidemicus . Ten of the 14 mares had detectable amounts of C3; however, the C3 had been cleaved and rendered nonfunctional. The importance of these findings in relationship to chronic uterine infections in the mare is discussed.