Characterization of antibodies elicited by XMRV infection and development of immunoassays useful for epidemiologic studies Xiaoxing Qiu1 email, Priscilla Swanson1 email, Ka-Cheung Luk1 email, Bailin Tu1 email, Francois Villinger2 email, Jaydip Das Gupta3 email, Robert H Silverman3 email, Eric A Klein4 email, Sushil Devare1 email, Gerald Schochetman1 email and John Hackett Jr1 email 1 Infectious Diseases R&D, Abbott Diagnostics, 100 Abbott Park Rd, Abbott Park, IL, 60064, USA 2 Department of Pathology, Emory University School of Medicine/Yerkes National Primate Research Center, 954 Gatewood Dr, Atlanta, GA, 30329, USA 3 Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Av, Cleveland, OH, 44195, USA 4 Glickman Urological and Kidney Institute and LRI, Cleveland Clinic Foundation, 9500 Euclid Av, Cleveland, OH, 44195, USA author email corresponding author email Retrovirology 2010, 7:68doi:10.1186/1742-4690-7-68 The electronic version of this article is the complete one and can be found online at: http://www.retrovirology.com/content/7/1/68 Received: 3 June 2010 Accepted: 17 August 2010 Published: 17 August 2010 2010 Qiu et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background Xenotropic Murine Leukemia Virus-related Virus (XMRV) is a human gammaretrovirus recently identified in prostate cancer tissue and in lymphocytes of patients with chronic fatigue syndrome. To establish the etiologic role of XMRV infection in human disease requires large scale epidemiologic studies. Development of assays to detect XMRV-specific antibodies would greatly facilitate such studies. However, the nature and kinetics of the antibody response to XMRV infection have yet to be determined. Results Three rhesus macaques were infected with XMRV to determine the dynamics of the antibody responses elicited by infection with XMRV. All macaques developed antibodies to XMRV during the second week of infection, and the predominant responses were to the envelope protein gp70, transmembrane protein p15E, and capsid protein p30. In general, antibody responses to gp70 and p15E appeared early with higher titers than to p30, especially in the early period of seroconversion. Antibodies to gp70, p15E and p30 persisted to 158 days and were substantially boosted by re-infection, thus, were identified as useful serologic markers. Three high-throughput prototype assays were developed using recombinant proteins to detect antibodies to these viral proteins. Both gp70 and p15E prototype assays demonstrated 100% sensitivity by detecting all Western blot (WB) positive serial bleeds from the XMRV-infected macaques and good specificity (99.5-99.9%) with blood donors. Seroconversion sensitivity and specificity of the p30 prototype assay were 92% and 99.4% respectively. Conclusions This study provides the first demonstration of seroconversion patterns elicited by XMRV infection. The nature and kinetics of antibody responses to XMRV in primates were fully characterized. Moreover, key serologic markers useful for detection of XMRV infection were identified. Three prototype immunoassays were developed to detect XMRV-specific antibodies. These assays demonstrated good sensitivity and specificity; thus, they will facilitate large scale epidemiologic studies of XMRV infection in humans.