Lipo-pam™ adjuvanted herpes zoster vaccine induces potent gE-specific cellular and humoral immune responses

Abstract

Herpes zoster (HZ), also known as shingles, is caused by the reactivation of latent varicella-zoster virus (VZV). Decreased VZV-specific T-cell immune responses significantly contribute to the development of HZ. Shingrix is a recombinant zoster vaccine that is currently used to prevent HZ. However, Shingrix has high reactogenicity and pain at the injection site due to QS21, one of the adjuvant components. In this study, we developed a new herpes zoster vaccine formulation called CVI-VZV-001, containing gE protein and a novel liposome-based adjuvant Lipo-pam™, which consists of two TLR agonists. We evaluated the immunogenicity of CVI-VZV-001 in mouse and rabbit models. CVI-VZV-001 elicited robust gE-specific T-cell immune responses and gE-specific antibody production. Specifically, CVI-VZV-001 induced polyfunctional CD4+ T cell populations that secrete multiple cytokines. Furthermore, CVI-VZV-001 sustained the gE-specific immune responses for up to six months after immunization. To ensure CVI-VZV-001's safety for further development, we conducted a good laboratory practice (GLP) toxicity test, which confirmed that CVI-VZV-001 is safe for use. At present, CVI-VZV-001 is undergoing phase I clinical trials. This study suggests that CVI-VZV-001 can be a potent candidate for the HZ vaccine with high immunogenicity and safety.