Specific Immunofluorescence Test for the Herpes-Type EB Virus of Burkitt Lymphoblasts, Authenticated by Electron Microscopy2

Abstract

Sera from rabbits immunized with purified herpes-type virus from cultured Burkitt lymphoblasts of the EB3 strain were conjugated with fluorescein isothiocyanate and used in an immunofluorescence test. Two sera brilliantly stained a proportion of EB3 cells, but failed to react with normal human lymphoid cells or human cells from HeLa cultures, embryo lung fibroblast cultures, and amnion cultures. The positive sera gave slight background staining when used unabsorbed, but this was removed completely by preliminary treatment with small amounts of normal human lymphoid-cell powder; the sera did not react with normal human serum on Immunoelectrophoresis. Control conjugated rabbit antiserum to a bacterial antigen did not stain the EB3 cells. Examination of samples of EB3 cells by the immunofluorescence test and electron microscopy in parallel showed 3 times fewer fluorescing cells than cells containing virus, with the particular criteria chosen for assessing positive fluorescence. Both fluorescing cells and cells seen in the electron microscope to contain virus were frequently degenerating. Where cells were tested for immunofluorescence and then flat-embedded and examined in the electron microscope, the fluorescence-positive cells were found to contain EB virus particles, whereas neighboring inert cells did not. The reasons for the belief that the immunofluorescence test is specific for cells containing EB virus are discussed.