[Preparation and characterization of a monoclonal antibody directed against bovine leukocytes].

A monoclonal antibody (MAb-M25) was obtained by immunizing BALB/C mice with tumour cells isoled from a familial thymic lymphosarcoma observed in Friesian cattle. The specificity of this MAb was assessed using PBL, lymphoids organs (lymph node, spleen, tonsil, Pleyer's patch) and non lymphoid tissues (liver, skin) from clinical normal cattle. Immunofluorescence and immunohistochemistry methods were used to characterise this monoclonal antibody. It reacted with 27% of peripheral blood lymphocytes and a large proportion of mononuclear cell in the lymphoid organ, in the thymic cortical, in the dermis and in the liver. It also stained lymphocytes of the mantle of follicules and thymocytes of the thymus cortex. The tissue distribution of M25 have a similarity with the human CD1c Mab and the bovine 20-27 MAb.