BROAD IMMUNOCYTOCHEMICAL LOCALIZATION OF THE FORMYLPEPTIDE RECEPTOR IN HUMAN ORGANS, TISSUES, AND CELLS

The formylpeptide receptor (FPR), previously found only on polymorphon uclear leukocytes and monocytes/macrophages, responds to both syntheti c N-formyl oligopeptides and those produced by bacteria. The cDNA for human FPR has been cloned and a rabbit polyclonal antiserum directed a gainst a synthetic 11-amino-acid peptide corresponding to the deduced carboxy-terminus has been produced. We have now extensively characteri zed and used the antibody to detect FPR on normal human tissues and ce ll types. The receptor antigen is present on some epithelial cells, es pecially those with a secretory function, and on some endocrine cells, e,g., follicular cells of the thyroid and cortical cells of the adren al. Liver hepatocytes and Kupffer cells are positive. Smooth muscle an d endothelial cells are also generally positive. In the brain and spin al cord, the neurons of the motor, sensory, and cerebellar systems, an d those of the parasympathetic and sympathetic systems stain positivel y. These data suggest that the putative endogenous agonist for FPR or an antigenically similar receptor reacts with cellular targets in the neuromuscular, vascular, endocrine, and immune systems.