A Herpes Simplex Virus Type 1 Human Asymptomatic CD8+ T-Cell Epitopes-Based Vaccine Protects Against Ocular Herpes in a "Humanized" HLA Transgenic Rabbit Model.

Immunology and Microbiology A Herpes Simplex Virus Type 1 Human Asymptomatic CD8 þ T-Cell Epitopes-Based Vaccine Protects Against Ocular Herpes in a ‘‘Humanized’’ HLA Transgenic Rabbit Model Ruchi Srivastava, 1 Arif A. Khan, 1 Jiawei Huang, 1 Anthony B. Nesburn, 1 Steven L. Wechsler, 1–3 and Lbachir BenMohamed 1,4,5 1 Laboratory of Cellular and Molecular Immunology, Gavin Herbert Eye Institute, University of California Irvine, School of Medicine, Irvine, California, United States Department of Microbiology and Molecular Genetics, University of California Irvine, School of Medicine, Irvine, California, United States 3 Center for Virus Research, University of California Irvine, Irvine, California, United States Department of Molecular Biology & Biochemistry Institute for Immunology, University of California Irvine, School of Medicine, Irvine, California, United States Correspondence: Lbachir BenMo- hamed, Laboratory of Cellular and Molecular Immunology, Gavin Her- bert Eye Institute; Ophthalmology Research Laboratories, Hewitt Hall, Room 2032, 843 Health Sciences Road, Irvine, CA 92697-4390, USA; Lbenmoha@uci.edu. RS and AAK contributed equally to the work presented here and should therefore be regarded as equivalent authors. Submitted: April 10, 2015 Accepted: May 23, 2015 Citation: Srivastava R, Khan AA, Huang J, Nesburn AB, Wechsler SL, BenMohamed L. A herpes simplex virus type 1 human asymptomatic CD8 þ T-cell epitopes-based vaccine protects against ocular herpes in a ‘‘humanized’’ HLA transgenic rabbit model. Invest Ophthalmol Vis Sci. 2015;56:4013–4028. DOI:10.1167/ iovs.15-17074 P URPOSE . A clinical vaccine that protects from ocular herpes simplex virus type 1 (HSV-1) infection and disease still is lacking. In the present study, preclinical vaccine trials of nine asymptomatic (ASYMP) peptides, selected from HSV-1 glycoproteins B (gB), and tegument proteins VP11/12 and VP13/14, were performed in the ‘‘humanized’’ HLA–transgenic rabbit (HLA-Tg rabbit) model of ocular herpes. We recently reported that these peptides are highly recognized by CD8 þ T cells from ‘‘naturally’’ protected HSV-1–seropositive healthy ASYMP individuals (who have never had clinical herpes disease). M ETHODS . Mixtures of three ASYMP CD8 þ T-cell peptides derived from either HSV-1 gB, VP11/ 12, or VP13/14 were delivered subcutaneously to different groups of HLA-Tg rabbits (n ¼ 10) in incomplete Freund’s adjuvant, twice at 15-day intervals. The frequency and function of HSV-1 epitope-specific CD8 þ T cells induced by these peptides and their protective efficacy, in terms of survival, virus replication in the eye, and ocular herpetic disease were assessed after an ocular challenge with HSV-1 (strain McKrae). R ESULTS . All mixtures elicited strong and polyfunctional IFN-c– and TNF-a–producing CD107 þ CD8 þ cytotoxic T cells, associated with a significant reduction in death, ocular herpes infection, and disease (P < 0.015). C ONCLUSIONS . The results of this preclinical trial support the screening strategy used to select the HSV-1 ASYMP CD8 þ T-cell epitopes, emphasize their valuable immunogenic and protective efficacy against ocular herpes, and provide a prototype vaccine formulation that may be highly efficacious for preventing ocular herpes in humans. Keywords: HSV-1, HLA transgenic rabbit, animal model, T cell, glycoprotein B, VP11/12, VP13/14, vaccine, ocular ith a staggering one billion individuals worldwide currently carrying herpes simplex virus type 1 (HSV-1), herpes remains one of the most prevalent viral infections of the eye. 1–7 Ocular herpes infection causes a spectrum of clinical manifestations ranging from blepharitis, conjunctivitis, and dendritic keratitis to disciform stromal edema and blinding stromal keratitis (HSK). 8,9 In the United States alone, over 450,000 people have a history of recurrent ocular HSV requiring doctor visits, antiviral drug treatments, and, in severe cases, corneal transplants. 10–12 Despite the availability of many intervention strategies, the global picture for ocular herpes continues to deteriorate. 13 Current antiviral drug therapies (e.g., acyclovir and derivatives) do not eliminate the virus and reduce recurrent herpetic disease by only approximately 45%. 14 The development of an effective vaccine would present an unparalleled alternative to antiviral drugs, as it would be a powerful and cost-effective means to reduce HSV-1 ocular infection and lessen associated blinding ocular herpetic disease (reviewed previously 1 ). Our long-term goal is to develop a vaccine to prevent HSV-1 infection and protect against ocular herpes disease. The most recent vaccine clinical trials that used recombinant HSV proteins failed to protect despite inducing strong HSV-specific neutralizing antibodies. These failures emphasize three major gaps in knowledge: the need to induce strong T-cell responses (in addition to humoral responses) for protection against ocular herpes, 15 the need to identify protective human herpes T-cell epitopes from HSV antigens (Ags) to be incorporated in the next generation HSV vaccines, 15 and the preclinical evaluation of protective efficacy of human herpes T-cell epitopes in a reliable animal model of ocular herpes infection and disease. One ‘‘common denominator’’ among previously failed vaccine clinical trials is that they either used the whole virus or whole HSV proteins (e.g., HSV glycoprotein B and/or D [gB Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc. iovs.arvojournals.org j ISSN: 1552-5783 W