Human eosinophil lysophospholipase: the sole protein component of Charcot-Leyden crystals.

Charcot-Leyden crystals (CLC), formed in vitro from human eosinophils, were recently shown to contain a protein identical in physicochemical characteristics to human eosinophil lysophospholipase. Monospecific antisera, prepared against homogeneous, chromatographically purified eosinophil lysophospholipase and against CLC formed in vitro, yielded precipitin lines fusing in a pattern of immunochemical identity on Ouchterlony analysis with disrupted eosinophils, purified lysophospholipase, and solubilized CLC protein. With antisera to the purified lysophospholipase, CLC present in vivo in human feces were demonstrated by indirect immunofluorescence to contain eosinophil lysophospholipase. Fecal CLC, purified by sequential gradient centrifugation, contained a single protein migrating identically to eosinophil lysophospholipase on SDS polyacrylamide gel electrophoresis. Solubilized fecal CLC were recrystallized to form characteristically-shaped CLC. Thus, naturally occurring CLC are formed solely of human eosinophil lysophospholipase.