IDENTIFICATION OF LEUKOCYTE SURFACE-ANTIGENS IN PARAFFIN-EMBEDDED BOVINE-TISSUES USING A MODIFIED FORMALIN DICHROMATE FIXATION

A modified fixative of formalin dichromate was combined with a cold em bedding procedure for the preservation of bovine leucocyte surface ant igens. Fourteen monoclonal antibodies recognizing seven bovine leucocy te surface antigens (BoCD1w2, BoCD4, BoCD8, BoWC1, BoWC3, BoWC4 and Bo IgM) were applied as primary antisera in a sensitive avidin-biotin-per oxidase complex detection method. The staining results were compared w ith those obtained in cryostat and routinely formalin-fixed sections o f corresponding tissue samples. Using the modified formalin dichromate fixative and the cold embedding procedure, all the leucocyte surface antigens tested were detectable immunohistologically in paraffin secti ons with a generally more distinct staining than in traditionally proc essed tissues. Morphological structures were better preserved than in cryostat sections but, to some extent, were poorer when compared with routinely formalin-fixed tissues. However, this method suggests that t here are only mild masking effects and provides an alternative to the use of unfixed material, particularly for morphological-immunohistoche mical investigations.