Production of laminin B2 chain protein and messenger RNA by a murine neutrophil precursor cell line, 32Dc13.

Laminin is a heterotrimeric glycoprotein that plays a central role in promoting neutrophil chemotaxis, motility, and attachment to basement membrane. Rabbit peritoneal exudate neutrophils stain positively for laminin, which is presumed to be of exogenous origin and bound to laminin receptors on the cell surface. We examined 32Dc13 cells, a murine neutrophil precursor cell line, by immunoprecipitation. Northern blot analysis, flow cytometry, and electron microscopy for the endogenous production of laminin. Our results demonstrate that 32Dc13 cells endogenously produce a laminin B2 chain protein and messenger RNA (mRNA) without producing any detectable A or B1 chain protein or mRNA. The B2 chain protein was not secreted by the cells; rather it could be detected on the cell surface after treatment of cells with neuraminidase. These findings suggest the possibility of a novel role for the laminin B2 chain in myeloid development and function.