Decay‐Accelerating Factor Is Expressed in the Human Endometrium and May Serve as the Attachment Ligand for Dr Pili of Escherichia coli

Abstract

PROBLEM: We evaluated the hypothesis that different tissue substructures in uteri may express decay accelerating factor (DAF), a complement regulatory protein that also may serve as ligand for bacterial attachment. METHOD: Purified Dr pili, anti‐Dr pili IgG, anti‐DAF (SCR‐3) IgG, and fluoresceinisothiocyanate‐conjugated secondary IgG were used for binding and inhibition experiments. RESULT: We observed staining of endometrial glands, spiral arterioles, and myometrial arteries with Dr adhesin (pili) and anti‐DAF (SCR‐3) IgG, and found variation in distribution and amount of Dr ligands in different individuals. Anti‐DAF (SCR‐3) IgG blocked the binding of Dr pili to the endometrium. CONCLUSION: Presence of DAF in endometrium may protect tissues from complement‐induced damage. Differences between individuals in DAF density in the endometrium may affect sensitivity to attachment of Dr‐bearing E. coli and/or complement activation.