Expression of Forssman antigen of avian lymphoblastoid cell lines transformed by Marek's disease virus or avian leukosis virus.

The expression of Forssman-type heterophile antigen on Marek's disease (MD) virus (MDV)-transformed cell lines, MDCC-MSBI 1, -HP1, -RP1 and -BP1, and avian leukosis virus (ALV)-transformed cell lines, LSCC-1104B1 and -1104X5 was investigated by membrane immunofluorescence and complement-dependent antibody cytotoxicity tests. Forssman antigen was detected on a high percentage of the cells in two ALV-transformed cell lines and on a smaller percentage of splenic lymphocytes from normal chicken. Of the MDV-transformed cell lines tested only the RP1 and BP1 cell lines, derived from transplantable MD tumours, expressed Forssman antigen, while the MSB1 and HP1 cell lines, derived from MD lymphomas, did not. Forssman antigen appears to be unrelated to MD tumour-associated surface antigen (MATSA).