Establishment and characterization of Epstein-Barr virus gp350-expressing transfected human lymphoid (Raji) cell clones.
Gp350, a late Epstein-Barr-virus (EBV) glycoprotein expressed on both the envelope of viral particles and EBV-producing cells, is also the candidate for the development of an anti-EBV subunit vaccine. This glycoprotein is thought to play an important role in anti-EBV immunity. However, studies on the role of this viral antigen in cellular cytotoxicity and other immune functions have been hampered by the lack of a suitable model expressing gp350. We describe here a study in which we successfully transfected a gp350-negative cell line resistant to natural-killer(NK)-cell activity (i.e., Raji) with a recombinant plasmid (pZIP-MA) containing the EBV-gp350 and the neomycin resistance gene. Three clones with a stable and strong expression of gp350 on their surface membrane, as demonstrated using a gp350-specific (i.e., 2LI0) monoclonal antibody (MAb) were isolated, characterized and used as targets in an antibody-dependent cellular cytotoxicity (ADCC) assay. However, gp350 expression on 2 of the 3 isolated clones was not recognized by an anti-gp350 MAb (72AI) which is specific to a unique gp350 epitope with a dual function (i.e., involved in both EBV binding to its target cell receptors and in inducing virus-neutralizing antibody). We have also found that gp350 expression on our 3 selected clones does not affect EBV-receptor (CR2) density. Our model of gp350-expressing, NK-cell-activity-resistant targets revealed very useful in determining that gp350 serves as a target antigen for EBV-specific ADCC. These gp350-expressing cell clones appear to represent a valuable tool for diagnostic purposes (i.e., for detecting and titrating gp350 antibodies in patients with EBV-associated diseases). Our approach should also prove useful for studying the expression of other cell-surface-associated viral and tumor antigens and their role in specific cellular immunity and immunosurveillance.
Khyatti
M
M
Department of Microbiology, University of Montreal, Quebec, Canada.
Patel
P C
PC
Menezes
J
J
D000911:Antibodies, Monoclonal; D000956:Antigens, Viral / Q000032:analysis / Q000235:genetics*; D002051:Burkitt Lymphoma; D002460:Cell Line; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D004854:Herpesvirus 4, Human / Q000235:genetics* / Q000276:immunology; D006801:Humans; D016366:Open Reading Frames; D014162:Transfection; D014763:Viral Matrix Proteins
D000911:Antibodies, Monoclonal; D000956:Antigens, Viral; C037662:EBV-associated membrane antigen, Epstein-Barr virus; D014763:Viral Matrix Proteins