Weinberg, AdrianaMuresan, PetronellaRichardson, KellyFenton, TerenceDominguez, TeresaBloom, AnthonyWatts, D. HeatherAbzug, Mark J.Nachman, Sharon A.Levin, Myron J.2016-01-042015Weinberg, Adriana, Petronella Muresan, Kelly Richardson, Terence Fenton, Teresa Dominguez, Anthony Bloom, D. Heather Watts, Mark J. Abzug, Sharon A. Nachman, and Myron J. Levin. 2015. “Heterogeneity of T Cell Responses to Pandemic pH1N1 Monovalent Vaccine in HIV-Infected Pregnant Women.” AIDS Research and Human Retroviruses 31 (11): 1170-1177. doi:10.1089/aid.2015.0151. http://dx.doi.org/10.1089/aid.2015.0151.0889-2229http://nrs.harvard.edu/urn-3:HUL.InstRepos:23993635Abstract We investigated the Th1 protective and regulatory T and B cell (Treg and Breg) responses to pH1N1 monovalent influenza vaccine (IIV1) in HIV-infected pregnant women on combination antiretroviral therapy (cART). Peripheral blood mononuclear cells (PBMCs) from 52 study participants were cryopreserved before and after vaccination and analyzed by flow cytometry. pH1N1-specific Th1, Treg, and Breg responses were measured in PBMCs after in vitro stimulation with pH1N1 and control antigen. The cohort analysis did not detect changes in pH1N1-Th1, Treg, or Breg subsets postvaccination. However, individual analyses distinguished subjects who mounted vigorous Th1 responses postvaccination from others who did not. Postvaccination, high pH1N1-Th1 correlated with high pH1N1-Treg and Breg responses, suggesting that low influenza effector responses did not result from excessive vaccine-induced immune regulation. High postvaccination pH1N1-Th1 responses correlated with baseline high PHA- and pH1N1-IFN-γ ELISpot and circulating CD4+CD39+% and CD8+CD39+% Treg, with low CD8+ cell numbers and CD19+FOXP3+% Breg, but not with CD4+ cell numbers or HIV viral load. These data highlight the heterogeneity of T cell responses to vaccines in HIV-infected individuals on cART. Predictors of robust Th1 responses to IIV include CD8+ cell numbers, T cell functionality, and circulating Breg and Treg.en-USJournal Article2016-01-0410.1089/aid.2015.0151