IMMUNOHISTOCHEMICAL DEMONSTRATION OF DIFFERENT LATENT MEMBRANE PROTEIN-1 EPITOPES OF EPSTEIN-BARR-VIRUS IN LYMPHOPROLIFERATIVE DISEASES

Aim-To compare the immunoreactivity of monoclonal antibodies S12 and C S1-4, which recognise different epitopes of the Epstein-Barr virus (EB V) latent membrane protein-1 (LMP-1), in EBV associated benign and mal ignant lymphoproliferative disorders and control tissues processed usi ng different methods. Results-Both monoclonal antibodies gave comparab le results on frozen tissue sections and formalin fixed, paraffin wax embedded samples from cases with Hodgkin's disease and infectious mono nucleosis. In all cases S12 stained more cells than CS1-4. For EBV ass ociated B and T non-Hodgkin's lymphomas, frozen tissue sections yielde d better LMP-1 staining results than formalin fixed material. Again, i n all these cases S12 stained more cells and gave stronger results tha n CS1-4. For EBV negative tissues, both monoclonal antibodies showed c ross-reactivity with melanocytic-like cells in the basal cell layer of the skin, synaptophysin-like staining in layers three and four of the cortex of the brain, and myelin-like staining in peripheral nerves an d peripheral ganglion cells. Staining with S12 was always much stronge r. Moreover, in contrast to CS1-4, S12 stained pancreatic islands in f ormalin fixed material but not in frozen tissue sections and sporadica lly stained solitary epithelial cells in the large bowel especially in formalin fixed tissue sections. CS1-4 also cross-reacted with myoepit helial cells around hair follicles and other adnexa of the skin. Concl usion-The results indicate that for optimal detection of LMP-1, S12 yi elds better results than CS1-4 and that tissue processing is very impo rtant especially when B and T non-Hodgkin's lymphomas are examined.