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

npj | vaccines Article Published in partnership with the Sealy Institute for Vaccine Sciences https://doi.org/10.1038/s41541-024-00939-4 Lipo-pam™ adjuvanted herpes zoster vaccine induces potent gE-specific cellular and humoral immune responses Check for updates 1 1 1 1 1 2 1234567890():,; 1234567890():,; Soo-Kyung Jeong , Su-Jin Ham , Seung-Hee Baek , Eun-Jung Jung , Hyun-Jin Jo , Hye-Ran Cha , Jae-Myun Lee2, Byung Cheol Ahn1, Jung Sun Yum1 & Eunyoung Chun1 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, CVIVZV-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. Varicella zoster virus (VZV) is an alpha herpes virus that affects the nervous and lymphatic systems. VZV causes varicella, commonly known as chickenpox, and herpes zoster (HZ), also known as shingles1. HZ occurs when VZV reactivates from the sensory ganglia and is likely due to insufficient cellular immunity to control reactivation2–4. VZV-induced HZ is characterized by a painful, blistering rash that typically appears on one side of the body or face, resulting in nerve damage and a range of other complications5–7. Postherpetic neuralgia (PHN) can develop in patients with HZ, causing pain even after the signs and symptoms of HZ have subsided, which can last for months, years, or even a lifetime7,8. Therefore, a prophylactic vaccine is essential to reduce the risk of HZ, especially for immunocompromised and elderly individuals who are more vulnerable to HZ. Currently, there are two types of vaccines used to protect HZ. One type is a live-attenuated vaccine, such as Zostavax (MSD, USA) and SKYZoster (SK bioscience, Korea), while the other is an adjuvanted subunit vaccine, Shingrix (GSK, Belgium). A live-attenuated vaccine contains a weakened live strain of the varicella-zoster virus that stimulates the immune system without causing disease in healthy individuals. However, it is not recommended for individuals with severe immunosuppression due to the risk of adverse reactions to the live virus9. Recently, a recombinant zoster vaccine, Shingrix, has replaced a live attenuated vaccine. Shingrix contains gE protein derived from the varicella-zoster virus and an adjuvant called AS01B, composed of liposomes formulated with cholesterol, monophosphoryl lipid A (MPL), and QS21. Although Shingrix is highly effective in preventing HZ, it can cause significant side effects with injection site pain and systemic reactions in some people. In particular, the proportion of people who received Shingrix experienced almost 24 times grade 3 of injection site pain compared to the placebo group10,11. This high reactogenicity of Shingrix is likely due to QS21, which is one of the components of adjuvant AS01B. QS21 is a saponin that induces inflammatory cytokines, resulting in T-helper 1 (Th1) responses12. However, the high reactogenicity of QS21, including lysis of cell membranes, hemolysis, and injection site pain, are major limiting factors in its use. We have developed a proprietary adjuvant called L-pampo™, based on Toll-like receptor (TLR) agonists. We have applied it to various vaccine platforms that target infectious diseases and cancers13–16. L-pampo™ is a complex of TLR2 and 3 agonists and synergistically induces both humoral and cellular immune responses. Specifically, L-pampo™ effectively induces a 1 R&D Center, CHA Vaccine Institute, Seongnam-si, Gyeonggi-do, Republic of Korea. 2Department of Microbiology and Immunology, Yonsei e-mail: ; University College of Medicine, Seoul, Republic of Korea. npj Vaccines | (2024)9:150 1 https://doi.org/10.1038/s41541-024-00939-4 Th1 response, which is critical for a therapeutic effect. Clinical safety for Lpampo™ has been proven through a phase 1/2a study and a phase 2b study involving up to 200 patients with Hepatitis B chronic infection. We have also developed a liposome-based formulation of L-pampo™ called Lipo-pam™. This formulation serves as an antigen delivery vehicle and immunostimulatory adjuvant. Lipo-pam™ integrates two lipid compositions, 1,2-Dioleoyloxy-3-trimethylammuium propane chloride (DOTAP) and 1,2Dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) to create a liposome bilayer that incorporates the TLR2 agonist. The TLR3 agonist is attached to the liposome surface. This unique structure of Lipo-pam™ facilitates the interaction with the immune cell membrane that leads to the activation of antigen-presenting cells and the induction of robust antigen-specific humoral, cellular immune responses. In this study, we formulated a recombinant herpes zoster vaccine containing gE antigen adjuvanted with Lipo-pam™, called CVI-VZV-001. We demonstrated that CVI-VZV-001 induced substantial VZV gE-specific cellular and humoral immune responses comparable with Shingrix in animal models. CVI-VZV-001 also increases polyfunctional CD4+ T cells that produce multiple cytokines, such as IFN-γ, IL-2, and TNF, essential for protective immunity. Furthermore, CVI-VZV-001 maintained durable vaccine-induced cellular immune responses for up to six months. Lastly, we evaluated the safety of CVI-VZV-001 in the animal models and observed no signs of toxicity or weight loss. Therefore, our finding suggests that CVIVZV-001 can be a potent HZ vaccine. Results gE/Lipo-pam™ formulations induce gE-specific cell-mediated immune responses We produced VZV gE proteins, then purified and verified them using Western blotting and size exclusion chromatography (Supplementary Article Fig. 1a−d). We then formulated Lipo-pam™ and characterized its physicochemical properties, including size, zeta potential, and polydispersity index (PDI) (Supplementary Fig. 2a−c). To examine the immunogenicity of gE/Lipo-pam™ vaccine candidates, we formulated gE/Lipo-pam™ candidates with different ratios of lipid component (...truncated)