The next generation of HCV vaccines: a focus on novel adjuvant development

ABSTRACT

Introduction

Considerable efforts have been made to treat and prevent acute and chronic infections caused by the hepatitis C virus (HCV). Current treatments are unable to protect people from reinfection. Hence, there is a need for development of both preventive and therapeutic HCV vaccines. Many vaccine candidates are in development to fight against HCV, but their efficacy has so far proven limited partly due to low immunogenicity.

Areas covered

We explore development of novel and powerful adjuvants to achieve an effective HCV vaccine. The basis for developing strong adjuvants is to understand the innate immunity pathway, which subsequently stimulates humoral and cellular immune responses. We have also investigated immunogenicity of developed adjuvants that have been used in recent studies available in online databases such as PubMed, PMC, ScienceDirect, Google Scholar, etc.

Expert opinion

Adjuvants are used as a part of vaccine formulation to boost vaccine immunogenicity and antigen delivery. Several FDA-approved adjuvants are used in licensed human vaccines. Unfortunately, no adjuvant has yet been proven to boost HCV immune responses to the extent needed for an effective vaccine. One of the promising approaches for developing an effective adjuvant is the combination of various adjuvants to trigger several innate immune responses, leading to activation of adaptive immunity.

KEYWORDS:

• Hepatitis c virus
• vaccine
• adjuvants
• immune responses
• clinical trials

Article highlights

• Despite advances in the direct-acting antivirals treatment, 2-3 million new individuals are infected each year.

• Hepatitis C virus causes acute and chronic infection and is one of the leading causes of hepatocellular carcinoma.

• Cellular immunity has a crucial role in spontaneous virus elimination.

• An effective HCV vaccine should induce robust, long-lived, and neutralizing antibodies as well as multispecific cellular immune responses involving CD4⁺/CD8⁺ T lymphocytes.

• The recent studies discuss exploring and developing novel and potent adjuvants to achieve an acceptable HCV vaccine.

• Several FDA-approved adjuvants are used in licensed human vaccines. Unfortunately, no adjuvant has yet been proven to boost HCV immune responses to the extent needed for an effective vaccine.

• The combination of various adjuvants can enhance the potency of HCV vaccines.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.