In vitro evaluation of cell-mediated immunity to Epstein-Barr herpesvirus by cell migration inhibition tests

Migration of peripheral leukocytes in samples from sensitized [Epstein-Barr virus (EBV) antibody-positive] humans was greatly inhibited when challenged by antigen prepared from EBV-producing P3HR-1 cells but not by antigen prepared from EBV-nonproducing RAJI cells, EBV-negative human fibroblasts, or epithelial cells. Such inhibition was not observed when peripheral leuocytes from subjects or neonates not sensitized to EBV were challenged. Similar results were obtained in a two-stage test when the same leukocyte samples were challenged in vitro by antigen prepared from P3HR-1 cells and the cell-free supernatant was assayed for migration inhibition factor (MIF) in the guinea pig macrophage migration inhibition test; migration of guinea pig peritoneal exudate cells was greatly inhibited by the supernatant filtrates of leukocyte cultures only from subjects positive for EBV-antibody. Furthermore, this inhibitory effect was not observed if supernatant filtrates from leukocyte cultures challenged by antigens prepared from RAJI cells, fibroblasts, or epithelial cells were used. The EBV antigen transformed peripheral leukocytes and induced early antigen production in RAJI cells; however, a "killed" preparation (by UV irradiation) was sufficient for eliciting MIF production.