Susceptibility to HIV-1 infection of a human B-lymphoblastoid cell line, DG75, transfected with subgenomic DNA fragments of Epstein-Barr virus.

We have previously shown that the presence of the EBV genome and active EBV infection in some Burkitt's lymphoma cell lines confer the susceptibility of HIV-1 infection in spite of the absence of surface CD4 receptors in these cells. In the present study we used an EBV genome negative Burkitt's lymphoma B-cell line, DG75, transfected with three different subgenomic fragments of EBV expressing the nuclear antigens (EBNA1 and EBNA2) and the latent membrane protein (LMP), respectively. Immunofluorescence analysis demonstrated CD4 expression in more than 90% of the EBNA1, EBNA2 and LMP transfected cell lines, whereas the antigen could only be detected in less than 4% of the parental DG75 cell line. Unlike the wild type DG75 line, the three transfected cell lines were shown to be susceptible to HIV-1 by both IFA and production of virions. Northern blotting of poly(A) selected mRNA of the four cell lines and hybridization to a human CD4 cDNA (pT4B) demonstrated a 3 kb band in all three EBNA1, EBNA2 and LMP transfected cells as well as in the wild type DG75 cells. Approximate quantification indicates equivalent level of T4 mRNA expression in the transfected cell lines as compared to T-cell lines (Hut-78, H9-9).