Paul M. CoplanSwati B. GuptaSheri A. DubeyPunnee PitisuttithumAlex NikasBernard MbeweEfthyia VardasMauro SchechterEsper G. KallasDan C. FreedTong Ming FuChristopher T. MastPilaipan PuthavathanaJames KublinKelly Brown CollinsJohn ChisiRichard PendameScott J. ThalerGlenda GrayJames McintyreWalter L. StrausJon H. CondraDevan V. MehrotraHarry A. GuessEmilio A. EminiJohn W. ShiverMerck Research LaboratoriesMahidol UniversityMalawi College of MedicineMinistry of Population and HealthUniversidade Federal do Rio de JaneiroUniversidade Federal de Sao PauloUniversity of WitwatersrandIntl. Partnership for MicrobicidesThe University of North Carolina at Chapel HillInternational AIDS Vaccine InitiativeInternational Partnership for Microbicides2018-06-212018-06-212005-05-01Journal of Infectious Diseases. Vol.191, No.9 (2005), 1427-1434002218992-s2.0-20244369447https://repository.li.mahidol.ac.th/handle/20.500.14594/17005Background. The genetic diversity of human immunodeficiency virus type 1 (HIV-1) raises the question of whether vaccines that include a component to elicit antiviral T cell immunity based on a single viral genetic clade could provide cellular immune protection against divergent HIV-1 clades. Therefore, we quantified the cross-clade reactivity, among unvaccinated individuals, of anti-HIV-1 T cell responses to the infecting HIV-1 clade relative to other major circulating clades. Methods. Cellular immune responses to HIV-1 clades A, B, and C were compared by standardized interferon-γ enzyme-linked immunospot assays among 250 unvaccinated individuals, infected with diverse HIV-1 clades, from Brazil, Malawi, South Africa, Thailand, and the United States. Cross-clade reactivity was evaluated by use of the ratio of responses to heterologous versus homologous (infecting) clades of HIV-1. Results. Cellular immune responses were predominantly focused on viral Gag and Nef proteins. Cross-clade reactivity of cellular immune responses to HIV-1 clade A, B, and C proteins was substantial for Nef proteins (ratio, 0.97 [95% confidence interval, 0.89-1.05]) and lower for Gag proteins (ratio, 0.67 [95% confidence interval, 0.62-0.73]). The difference in cross-clade reactivity to Nef and Gag proteins was significant (P < .0001). Conclusions. Cross-clade reactivity of cellular immune responses can be substantial but varies by viral protein. © 2005 by the Infectious Diseases Society of America. All rights reserved.Mahidol UniversityMedicineArticleSCOPUS10.1086/428450