Abstract
Antisera produced in rabbits against Marek''s disease lymphoma cells and against 4 lymphoma-derived cell lines (HPRS lines 1 and 2, MSB-1 and RPL-1) appeared, after extensive absorption with normal chicken cells, to react specifically by indirect immunofluorescent staining with antigens unique to Marek''s disease tumor cells. The antigens present on the 4 cell lines were shown by antiserum titration and absorption tests to be related but not identical. The possibility was discussed that cellular transformation by Marek''s disease virus involved the modification of a normal lymphocyte antigen, and the modification of different allotypes of this antigen results in related but not identical neoantigens.