A Novel Human Leukocyte Antigen (HLA) Transgenic Rabbit Model to Evaluate Human CD8+ T-Cell Epitope-Based Immunotherapies Against Spontaneous HSV-1 Reactivation

Abstract

Methods: : HLA-A*0201 transgenic rabbits were immunized subcutaneously 3X with three lipopeptides bearing HLA-A*0201-restricted human epitopes at 2-weeks intervals at a dose of 100 ug/rabbit. Control rabbits received saline alone. Ten days after the last immunization, HSV-specific CD8⁺T-cell immune responses were analyzed in spleen, conjunctiva, and TG by CFSE assay. The frequency of HSV peptide-specific CD8+ T-cells were measured using peptide-specific/HLA-A*0201 tetramers. The protective efficacy of the lipopeptides against ocular challenge with HSV-1 was analyzed by slit lamp for eye disease and by virus titration in tears.

Results: : Lipopeptide immunizations induced strong HSV-1 and peptide-specific CD8+ immune responses in the spleen, conjunctiva and TG of HLA-A*0201 Tg rabbits. (2) Lipopeptide immunization induced protective immunity in HLA-A*0201 Tg rabbits as demonstrated by decreased eye disease and decreased virus replication.

Conclusions: : This is the first report showing that human CD8⁺+ T cell epitopes can protect against primary HSV-1 infection and disease in humanized HLA-A*0201 transgenic rabbits. This HLA Tg rabbit model will allow us for the first time to investigate whether therapeutic immunization of latently infected rabbits with human CD8+ T-cell epitopes will decrease HSV-1 spontaneous reactivation and reduce or eliminate HSK.

Keywords: herpes simplex virus • immunomodulation/immunoregulation • transgenics/knock-outs