[Analysis of Epstein-Barr virus transformation of human lymphocytes: susceptibility of B lymphocyte subpopulations and differentiation stage of the transformed cells].

The subpopulations of B lymphocytes in human adult peripheral blood which are susceptible to infection and transformation by Epstein-Barr virus (EBV), and also the stage of EBV-transformed cells in B cell differentiation lineage were identified. The EBV susceptibility were analyzed by two-color immunofluorescence and colony formation in semisolid agar. Surface Ig-bearing lymphocytes of 3 major Ig classes, IgM, IgG, and IgA, in peripheral blood expressed viral nuclear antigen (EBNA) after exposure to the virus, indicating that all these subpopulations are susceptible to EBV infection. In contrast, cytoplasmic Ig-positive lymphocytes were totally resistant to infection. The Ig-positive cells of either Ig class proliferated equally after EBV infection and formed colonies in semisolid agar, thereby showing that these subpopulations are also susceptible to transformation by EBV. Analysis of clonally transformed cells originating from each target cell by using a series of newly developed monoclonal antibodies to B cell differentiation antigens showed that EBV-transformed cells corresponded to the immunoblast stage of B cell differentiation. These data suggest that EBV infects and transforms mature B lymphocytes, and makes them differentiated to the more advanced immunoblast stage within the terminal B cell differentiation process.