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 May 1, 2013
Citation Information: J Clin Invest. 2013;123(6):2629-2642. https://doi.org/10.1172/JCI64704.
View: Text | PDF
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

×

Figure 1

Expression and binding characteristics of DNA vaccine constructs.

Options: View larger image (or click on image) Download as PowerPoint
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).