Native early antigen of Epstein-Barr virus, a promising antigen for diagnosis of nasopharyngeal carcinoma

• Published in: Journal of medical virology Vol. 79; no. 11; pp. 1710 - 1721
• Main Authors: Paramita, Dewi K, Fachiroh, Jajah, Artama, Wayan T, van Benthem, Eric, Haryana, Sofia M, Middeldorp, Jaap M
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.11.2007; Wiley-Liss
• Subjects: Action of physical and chemical agents; Animals; Antigens, Viral - genetics; Antigens, Viral - immunology; Baculoviridae - genetics; Biological and medical sciences; Cell Line; Cells, Cultured; diagnosis; early antigen; Enzyme-Linked Immunosorbent Assay; Epstein-Barr virus; Fundamental and applied biological sciences. Psychology; Herpesvirus 4, Human - immunology; Human viral diseases; Humans; IgA-ELISA; Immunoglobulin A - blood; Immunoglobulin G - blood; Infectious diseases; Medical sciences; Microbiology; Miscellaneous; nasopharyngeal carcinoma; Nasopharyngeal Neoplasms - diagnosis; Nasopharyngeal Neoplasms - virology; Recombinant Proteins - genetics; Recombinant Proteins - immunology; serology; Spodoptera; Viral diseases; Virology; Gammaherpesvirinae; IgA; nasopharyngeal carcinoma; Carcinoma; Herpesviridae; Early antigen; Nasopharynx; Serology; Epstein Barr virus; Malignant tumor; Enzyme immunoassay; IgA-ELISA; Virus; Epstein-Barr virus; Diagnosis; ELISA assay
• ISSN: 0146-6615; 1096-9071
• DOI: 10.1002/jmv.20987

The Epstein-Barr virus (EBV) early antigen (EA) complex consists of multiple proteins with relevance for diagnosis of acute, chronic and malignant EBV related diseases, including nasopharyngeal carcinoma (NPC). In a recent study, it was found that the molecular diversity of EBV-specific IgG and IgA antibody responses in NPC patients and demonstrated that these reflect independent B-cell triggering leading to distinct EBV antigen-recognition profiles. The fine-specificity of NPC-related IgG and IgA responses was explored further against defined recombinant and synthetic EBV-EA antigens using immunofluorescence, immunoblot and ELISA techniques and determined their diagnostic value in a large panel of sera from NPC (n = 154), non-NPC tumor patients (n = 133), acute mononucleosis patients (n = 70) and healthy EBV carriers (n = 259). Individual recombinant EBV-EA markers yielded sensitivity/specificity values not exceeding 86%, whereas selected EA-specific peptide epitopes were rather poorly recognized by IgG and IgA antibodies in NPC sera. Surprisingly, we found that a "low salt" native EA-protein extract reproducibly prepared from purified nuclei of EA-induced HH514 cells, and containing characteristic EA(D)-polypeptides, such as p47-54 (BMRF1), p138 (BALF2), p55-DNAse (BGLF5), and p65-TK (BXLF1), but without viral capsid (VCA) or nuclear antigen (EBNA) reactivity, gave highest sensitivity (90.4%) and specificity (95.5%) values for NPC diagnosis in both IgG and IgA ELISA. The data support further the notion that EBV-EA reactive IgG and IgA antibodies in NPC patients are directed against distinct conformational and--in part--linear epitopes on EBV-specific proteins, barely recognized in other EBV-related syndromes. The use of a defined native EBV EA-specific antigen opens the way to further improve serological diagnosis of NPC. J. Med. Virol. 79:1710-1721, 2007. © 2007 Wiley-Liss, Inc.