Characterization of monoclonal antibodies against porcine pulmonary alveolar macrophages of gnotobiotic miniature swine.

There is no sufficient porcine specific antibody available to investigate the ontogeny and development of porcine pulmonary alveolar macrophage (PAM). Therefore, several mouse anti-porcine macrophage mAbs have been produced and characterized in this study. First, the monoclonal antibody PM18-7, an IgG1, kappa isotype, bound to 91% of PAM, 6% of monocytes, and 2% of granulocytes indicating PM18-7 was found to be PAM specific. Monocyte derived macrophages could not be induced to express the PM18-7 antigen by culture. PM18-7 was immunoprecipitated with a molecule of 260 kDa under non-reducing conditions and with that of 130 kDa under reducing conditions in SDS-PAGE. Second, the monoclonal antibody PM3-15, an IgG1, kappa isotype, bound to 92% of PAM, 86% of monocytes, and 3% of granulocytes indicating PM3-15 was mononuclear phagocyte specific. PM3-15 was immunoprecipitated with a molecule of 245 kDa under non-reducing conditions and those of 150, 95 kDa under reducing conditions in SDS-PAGE. Third, the monoclonal antibody PM16-6, an IgM isotype, bound to 82% of PAM, 89% of monocytes, and 82% of granulocytes indicating PM16-6 recognizes those cells of myeloid lineage such as macrophages, monocytes and granulocyte. The antigen immunoprecipitated by PM16-6 was 120 kDa under non-reducing conditions and was 75, 25 kDa under reducing conditions. Finally, the antigen bound to PM18-7 was identified as ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1, CD203a), PM3-15 was figured out as integrin alpha M beta 2 precursor (ITGaM, CD11b) and PM16-6 was identified as Thimet oligopeptidase (THOP-1) by the LC-MS/MS protein sequencing method.