Detection and analysis of the 80-kd lipopolysaccharide receptor in macrophages derived from Lpsn and Lpsd mice.

An 80-kd lipopolysaccharide (LPS)-binding protein with specificity for the lipid A region has been identified on lymphocyte and macrophage membranes. In an attempt to gain insight into the hyporesponsiveness of C3H/HeJ (Lpsd) mice to LPS, an affinity-purified rabbit polyclonal IgG with specificity for this receptor was used to compare the expression and distribution of the 80-kd LPS receptor on thioglycollate-elicited peritoneal macrophages derived from normal (Lpsn) and (Lpsd) mice. By enzyme-linked immunosorbent assay, immunofluorescence microscopy, and flow cytometry, macrophages from Lpsn and Lpsd mice showed comparable expression of the 80-kd LPS receptor, although only a subpopulation of macrophages from both strains express it. Macrophages from both strains showed indistinguishable surface distribution of the 80-kd LPS receptor, as determined by confocal microscopy and analysis using an anchored cell analysis station. Treatment of macrophages with interferons, protein-rich LPS, or glucocorticoids, agents known to modulate a variety of macrophage cell surface markers and receptors, failed to alter expression of the 80-kd receptor. These findings support the hypothesis that the hyporesponsiveness of the Lpsd mouse strains to LPS is not due to an absence of receptors but rather is distal to binding of LPS and most likely attributable to a failure of these macrophages to transduce the signal derived at the cell surface to the interior of the cell.