Monoclonal and polyclonal antibodies against Epstein-Barr virus nuclear antigen 5 (EBNA-5) detect multiple protein species in Burkitt's lymphoma and lymphoblastoid cell lines.
The Epstein-Barr virus nuclear antigen 5 (EBNA-5) is encoded by highly spliced mRNA from the major IR1 (BamHI-W) repeat region of the virus genome. A mouse monoclonal antibody, JF186, has been raised against a synthetic 18-amino-acid peptide deduced from the EBNA-5 message of B95-8 and Raji cells. The antibody showed characteristic coarse nuclear granules by indirect immunofluorescence and revealed multiple EBNA-5 species by immunoblotting and immunoprecipitation. The B95-8 line itself and all B95-8 virus-carrying cells, whether lymphoblastoid cell lines or in vitro-converted sublines of Epstein-Barr virus (EBV)-negative Burkitt's lymphoma (BL) lines, were EBNA-5 positive. Among 36 cell lines carrying different EBV strains, only 10 expressed the B95-8-Raji-prototype EBNA-5 recognized by JF186; this was probably due to genetic variation in the epitope recognized by JF186, as shown for P3HR-1. Human antibodies, affinity purified against EBNA-5-JF186 immunoprecipitates, detected EBNA-5 in the majority of EBV-positive BL lines and in all lymphoblastoid cell lines containing the BL-derived viruses. Thus, EBNA-5 can be expressed by all virus isolates examined, but is down-regulated, together with other latent gene products, in a minority of BL lines which have a particular cellular phenotype. EBNA-5 was detected as a ladder of protein species of 20 to 130 kilodaltons (kDa), with a regular spacing of 6 to 8 kDa, consistent with the coding capacity of the combined BamHI-W 66- and 132-base-pair exons, together with shifts of 2 to 4 kDa, consistent with the size of the separate 66- and 132-base-pair exons. Multiple EBNA-5 proteins can be expressed by the single cell as shown by cloning of newly infected cells.
Finke
J
J
Department of Tumor Biology, Karolinska Institute, Stockholm, Sweden.
Rowe
M
M
Kallin
B
B
Ernberg
I
I
Rosén
A
A
Dillner
J
J
Klein
G
G
D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000276:immunology*; D000914:Antibodies, Viral / Q000235:genetics / Q000276:immunology; D000956:Antigens, Viral / Q000032:analysis* / Q000276:immunology; D002051:Burkitt Lymphoma / Q000382:microbiology; D002460:Cell Line; D002461:Cell Line, Transformed; D002467:Cell Nucleus / Q000276:immunology; D019309:Epstein-Barr Virus Nuclear Antigens; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D005814:Genes, Viral; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000276:immunology* / Q000648:ultrastructure; D006801:Humans; D006825:Hybridomas; D007118:Immunoassay; D010641:Phenotype
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral; D019309:Epstein-Barr Virus Nuclear Antigens