MONOCLONAL-ANTIBODIES TO A HIGH-MOLECULAR-WEIGHT ISOFORM OF PORCINE CD45 - BIOCHEMICAL AND TISSUE DISTRIBUTION ANALYSES

This report describes the obtention and characterization of two monocl onal antibodies (mAbs), 6B3/7 [mAb 6B3/7 was submitted to the Second I nternational Swine CD Workshop, where it has been assigned to CD45R] a nd 3C3/9, which recognize the isoform of highest molecular weight of p orcine CD45. This conclusion is based on their cell reactivity and tis sue distribution, identical to that reported for the human high molecu lar weight isoform of CD45, and on data from immunoprecipitation and i mmunoblotting analyses which show that these mAbs react with the large st polypeptide of those precipitated by mAb 2A5, that recognizes an ep itope shared by all CD45 isoforms, These mAbs react with 60% Of periph eral blood mononuclear cells (PBMC) but not with alveolar macrophages, granulocytes, platelets or erythrocytes. Antigen expression on PBMC i s heterogeneous and is reduced after in vitro activation with mitogens , B cells and CD8(+) T cells express more antigen than CD4(+) T cells. Using immunoperoxidase techniques, the antigen was detected on B cell areas of lymph nodes and Peyer's patches, and on a subpopulation of m edullary thymocytes. These mAbs will be useful reagents for functional and phenotypic analysis of porcine lymphoid cell populations by flow cytometry and immunohistochemistry. (C) 1997 Elsevier Science B.V.