CHARACTERIZATION OF MONOCLONAL-ANTIBODIES SPECIFIC FOR MONOCYTES, MACROPHAGES AND GRANULOCYTES FROM PORCINE PERIPHERAL-BLOOD AND MUCOSAL TISSUES

A panel of four monoclonal antibodies produced in our laboratory, MIL1 , MIL2, MIL3, MIL4, and the type-specific monocyte/granulocyte marker 74-22-15 were used to isolate and to discriminate between monocytes, m acrophages and granulocytes derived from porcine peripheral blood, lun g and gut lamina propria. Two-colour flow cytometry and cell sorting s howed that while no monoclonal antibody was specific for just a single cell population, each cell type had a unique and characteristic combi nation of surface antigens. These differences could be used to identif y and purify monocytes, macrophages, neutrophils, eosinophils and baso phils from the three different sites. The study also demonstrated simi larities and differences within cell types from the same site and from different sites: polymorphonuclear neutrophils (PMN) from peripheral blood were subdivided into two subpopulations by the presence or absen ce of the surface antigen recognized by MIL4, while PMN from alveolar lavage did not express this antigen. Peripheral blood eosinophils were also divided into subpopulations by the presence or absence of the sa me surface antigen. Lamina propria eosinophils strongly expressed the MIL4 marker and differed morphologically from blood eosinophils. Perip heral blood basophils and lamina propria mast cells were morphological ly similar and expressed similar antigens. Monocytes and alveolar macr ophages also expressed the same surface antigens.