PD1-based DNA vaccine amplifies HIV-1 GAG-specific CD8+ T cells in mice
Jingying Zhou, … , Kwok-Yung Yuen, Zhiwei Chen
Jingying Zhou, … , Kwok-Yung Yuen, Zhiwei Chen
Published June 3, 2013; First published May 1, 2013
Citation Information: J Clin Invest. 2013;123(6):2629-2642. https://doi.org/10.1172/JCI64704.
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Categories: Research Article Immunology

PD1-based DNA vaccine amplifies HIV-1 GAG-specific CD8+ T cells in mice

Abstract

Viral vector–based vaccines that induce protective CD8+ T cell immunity can prevent or control pathogenic SIV infections, but issues of preexisting immunity and safety have impeded their implementation in HIV-1. Here, we report the development of what we believe to be a novel antigen-targeting DNA vaccine strategy that exploits the binding of programmed death-1 (PD1) to its ligands expressed on dendritic cells (DCs) by fusing soluble PD1 with HIV-1 GAG p24 antigen. As compared with non–DC-targeting vaccines, intramuscular immunization via electroporation (EP) of the fusion DNA in mice elicited consistently high frequencies of GAG-specific, broadly reactive, polyfunctional, long-lived, and cytotoxic CD8+ T cells and robust anti-GAG antibody titers. Vaccination conferred remarkable protection against mucosal challenge with vaccinia GAG viruses. Soluble PD1–based vaccination potentiated CD8+ T cell responses by enhancing antigen binding and uptake in DCs and activation in the draining lymph node. It also increased IL-12–producing DCs and engaged antigen cross-presentation when compared with anti-DEC205 antibody-mediated DC targeting. The high frequency of durable and protective GAG-specific CD8+ T cell immunity induced by soluble PD1–based vaccination suggests that PD1-based DNA vaccines could potentially be used against HIV-1 and other pathogens.

Authors

Jingying Zhou, Allen K.L. Cheung, Zhiwu Tan, Haibo Wang, Wenbo Yu, Yanhua Du, Yuanxi Kang, Xiaofan Lu, Li Liu, Kwok-Yung Yuen, Zhiwei Chen

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Figure 1

Expression and binding characteristics of DNA vaccine constructs.

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Expression and binding characteristics of DNA vaccine constructs. (A) Sc...
(A) Schematic representation of constructs encompassing the soluble form of PD1 (sPD1) or with 2 amino acid deletions essential for binding with PD-L1/L2 (sΔPD1), p24, and rabbit Fc under the CMV promoter, denoted as sPD1-p24fc, sΔPD1-p24fc, and p24fc, respectively. All constructs contain a tissue plasminogen activator (tPA) signal sequence. Rabbit Fc was used as a tag for purification and detection purposes. (B) Expression of fusion constructs as purified recombinant proteins examined by Western blot. Upper and lower blots show proteins detected by anti-HIV GAG or anti-rabbit Fc antibody, respectively. Smaller-sized bands (lower panel arrows) represent p24fc, while the larger-sized bands (upper panel arrows) represent sPD1-p24fc or sΔPD1-p24fc. Lanes are identified by the legend and numbers in kDa indicate marker sizes. (C) 293T cells were transiently transfected with PD-L1 or PD-L2 expression vectors, and the binding profiles of recombinant proteins were examined by flow cytometry using anti-rabbit Fc-FITC detection antibody (gray line). Controls included transfected 293T cells stained with anti-rabbit Fc-FITC antibody (negative, shaded line) or anti-mouse PD-L1 or L2 antibodies (positive, solid line).