MEASUREMENT OF MOUSE ANTIPHOSPHOLIPID ANTIBODIES TO SOLID-PHASE MICROSPHERES BY BOTH FLOW CYTOFLUOROMETRY AND ALCIAN BLUE-PRETREATED MICROTITRE PLATES IN AN ELISA

Conventional solid-phase immunoassays measuring interactions between a nti-phospholipid antibodies and phospholipids are generally characteri zed by problems of reproducibility and high levels of non-specific bin ding. Here we describe two immunoassays based on the use of phospholip ids in the form of solid-phase microspheres to measure the presence of anti-phospholipid antibodies in sera. Following the production of ant ibodies in mice against liposomes containing lipid A, we show that flo w cytofluorometric analysis provides a reproducible and sensitive way to detect anti-phospholipid antibodies, We also present a sensitive, r apid and reproducible enzyme-linked immunosorbent assay (ELISA) using Alcian blue pretreated microtitre plates and solid-phase microspheres as coating antigen. This ELISA permitted the detection of antibodies t o 1/1000 dilution, while untreated plates gave negative results, Such modified ELISA procedures may be applicable to other types of molecule exhibiting solid-phase binding problems e.g. synthetic peptides (J. I mmunol. Methods 175 (1994) 131-135).