Monoclonal antibodies against chicken Bu-1a and Bu-1b alloantigens.

The production and characterization of monoclonal antibodies (mAbs) against chicken B cell surface alloantigens, Bu-1a and Bu-1b, is described. Flow cytometric analysis using these mAbs demonstrates that Bu-1 gene locus does not show allelic exclusion. Two color fluorescence analysis using simultaneous surface marker labeling and DNA staining shows that the expression of Bu-1 antigen is not restricted to a specific phase of the cell cycle. Earlier findings that Bu-1 locus is not linked to the MHC locus are confirmed. Furthermore, data is presented that Bu-1 antigen expression is not entirely B cell restricted. Apparently a fraction of larger mononuclear cells with typical light scatter characteristics in flow cytometry also bear this marker. MAbs against both allelic Bu-1 antigens are beneficial tools e.g. in typing of chicken lines and in studies on chicken B cell differentiation.