Autoantibodies to laminin and other basement membrane proteins in sera from monkeys with histories of reproductive failure identified by cultures of whole rat embryos.

Head-fold-stage rat embryos cultured on sera taken from monkeys with histories of reproductive failure had an abnormality frequency of 97% compared with only 7% on sera taken from monkeys with excellent reproductive histories. For a group of these poor reproducers, the toxicity of their sera was associated with the immunoglobulin G (IgG) fraction. These IgG fractions bound to Reichert's membrane and other basement membranes of the embryo. For one monkey, the IgG specifically reacted with a 41 kDa polypeptide of Reichert's membrane, while for two others binding was to laminin, type IV collagen, and several other minor polypeptides of Reichert's membrane. For serum from one monkey, the toxicity to cultured rat embryos was eliminated by absorption with laminin but not type IV collagen.