A MOUSE MONOCLONAL-ANTIBODY REACTING WITH SWINE LEUKOCYTES - A FLOW CYTOMETRIC AND IMMUNOHISTOCHEMICAL STUDY

A mouse monoclonal antibody (Mab) was prepared by immunization of Balb /c mice with porcine peripheral blood mononuclear cells. Its reactivit y was studied by flow cytometry and immunohistochemistry. By flow cyto metry 75-90% of blood lymphocytes and 93-97% of blood granulocytes sho wed positivity, while all monocytes were labelled. The specificity of the Mab was investigated further by immunohistochemical methods using different tissues of swine. Both cortical and medullary thymocytes str ongly expressed the target antigen of Mab 335-2. Intensive staining of T cell dependent areas in the lymph nodes, spleen and tonsils was als o observed. Many positive cells occurred in the red pulp of the spleen . In the non-lymphoid tissues no organ-specific staining was observed, except for the connective tissue which contained scattered positive c ells. Kupffer's cells and some glial cells reacted with this Mab. Thes e results suggest that this novel Mab recognizes a major antigen prese nt on immature and mature T cells; however, subpopulations of myeloid cells (neutrophils, monocytes, and some types of macrophages) share th is antigen.