Boosting SIV-specific CD8+ T cell responses prior to ART interruption extends time to SIVmac239 rebound
Were R. Omange, Benjamin D. Varco-Merth, Omo Fadeyi, Alejandra Marenco, Hiroshi Takata, Derick M. Duell, William D. Goodwin, Paula Armitage, Christine M. Fennessey, Emek Kose, Taina T. Immonen, Ewelina Kosmider, William J. Bosche, Randy Fast, Chris Homick, Kelli Oswald, Rebecca Shoemaker, Rachele Bochart, Rhonda MacAllister, Caralyn S. Labriola, Jeremy V. Smedley, Michael K. Axthelm, Paul T. Edlefsen, Brandon F. Keele, Jeffrey D. Lifson, Janina Gergen, Benjamin Petsch, Susanne Rauch, Louis J. Picker, Afam A. Okoye
Were R. Omange, Benjamin D. Varco-Merth, Omo Fadeyi, Alejandra Marenco, Hiroshi Takata, Derick M. Duell, William D. Goodwin, Paula Armitage, Christine M. Fennessey, Emek Kose, Taina T. Immonen, Ewelina Kosmider, William J. Bosche, Randy Fast, Chris Homick, Kelli Oswald, Rebecca Shoemaker, Rachele Bochart, Rhonda MacAllister, Caralyn S. Labriola, Jeremy V. Smedley, Michael K. Axthelm, Paul T. Edlefsen, Brandon F. Keele, Jeffrey D. Lifson, Janina Gergen, Benjamin Petsch, Susanne Rauch, Louis J. Picker, Afam A. Okoye
View: Text | PDF
Research Article AIDS/HIV Immunology

Boosting SIV-specific CD8+ T cell responses prior to ART interruption extends time to SIVmac239 rebound

Abstract

HIV/SIV-specific CD8+ T cell responses are typically unable to control viral rebound following antiretroviral therapy (ART) interruption (ATI). To investigate whether enhancing the magnitude and activation of SIV-specific CD8+ T cells at the time of ATI can improve the immune interception of reactivating SIV infections, we vaccinated SIVmac239-infected rhesus macaques (RMs) on ART, boosting immediately prior to ATI, with a nucleoside-unmodified mRNA vaccine expressing SIVmac239 Gag (mRNA/SIVgag) alone or in combination with Nef (mRNA/SIVnef) and Pol (mRNA/SIVpol). The mRNA/SIVgag vaccine was effective in boosting Gag-specific CD8+ T cells in blood and lymphoid tissues. Following ATI, the mRNA/SIVgag vaccine group showed a significant delay in time to measurable viral rebound compared with controls and manifested lower plasma viral loads (PVLs) for up to 6 weeks after rebound. Similarly, RMs that received mRNA/SIVgag, mRNA/SIVnef, and mRNA/SIVpol also manifested a delay in SIV rebound compared with controls, suggesting that boosting SIV-specific CD8+ T cells during ATI can enhance early immune targeting of reactivating SIV infections. However, viral control was not sustained long term as PVLs were similar across vaccinees and controls by 24 weeks after rebound, highlighting the need for adjunctive therapies to improve the durability of virologic control elicited by CD8+ T cell–targeting vaccines.

Authors

Were R. Omange, Benjamin D. Varco-Merth, Omo Fadeyi, Alejandra Marenco, Hiroshi Takata, Derick M. Duell, William D. Goodwin, Paula Armitage, Christine M. Fennessey, Emek Kose, Taina T. Immonen, Ewelina Kosmider, William J. Bosche, Randy Fast, Chris Homick, Kelli Oswald, Rebecca Shoemaker, Rachele Bochart, Rhonda MacAllister, Caralyn S. Labriola, Jeremy V. Smedley, Michael K. Axthelm, Paul T. Edlefsen, Brandon F. Keele, Jeffrey D. Lifson, Janina Gergen, Benjamin Petsch, Susanne Rauch, Louis J. Picker, Afam A. Okoye

×

Figure 2

mRNA/SIVgag vaccination induces robust CD8+ T cell responses in SIV-infected RMs on ART.

Options: View larger image (or click on image) Download as PowerPoint
mRNA/SIVgag vaccination induces robust CD8+ T cell responses in SIV-infe...
(A–D) Comparison of SIV Gag–specific T cell responses in RMs from the mRNA/SIVgag group versus the mRNA/control group: CD8+ T cell responses in blood (A) and BAL (B), and CD4+ T cell responses in blood (C) and BAL (D). Data represent mean frequencies (n = 8, +SEM). (E and F) Frequencies of peripheral blood CD8+ T cells specific for SIV Gag-CM9 (E) and Tat-SL8 (F), as determined by MHC-I multimer staining as described in Methods. (G) Comparison of SIV Gag–specific CD8+ T cell responses in PLNs, MLNs, BM, and spleen. Each data point represents an individual RM. Box-and -whisker plots show jittered points, a box from first to third quartiles (IQR), and a line at the median, with whiskers down to the minimum and up to the maximum value. Statistical significance between groups was determined by Wilcoxon’s rank-sum test; P values ≤ 0.05 are indicated.