Multi-Epitope Peptide-Based and Vaccinia-Based Universal Influenza Vaccine Candidates Subjected to Clinical Trials.

Syazwani Romeli,Sharifah Syed Hassan,Wei Boon Yap

doi:10.21315/mjms2020.27.2.2

Abstract

In light of the limited protection conferred by current influenza vaccines, immunisation using universal influenza vaccines has been proposed for protection against all or most influenza sub-types. The fundamental principle of universal influenza vaccines is based on conserved antigens found in most influenza strains, such as matrix 2, nucleocapsid, matrix 1 and stem of hemagglutinin proteins. These antigens trigger cross-protective immunity against different influenza strains. Many researchers have attempted to produce the conserved epitopes of these antigens in the form of peptides in the hope of generating universal influenza vaccine candidates that can broadly induce cross-reactive protection against influenza viral infections. However, peptide vaccines are poorly immunogenic when applied individually owing to their small molecular sizes. Hence, strategies, such as combining peptides as multi-epitope vaccines or presenting peptides on vaccinia virus particles, are employed. This review discusses the clinical and laboratory findings of several multi-epitope peptide vaccine candidates and vaccinia-based peptide vaccines. The majority of these vaccine candidates have reached the clinical trial phase. The findings in this study will indeed shed light on the applicability of universal influenza vaccines to prevent seasonal and pandemic influenza outbreaks in the near future.

Highlights

Influenza is an acute respiratory infection caused by influenza viruses
On top of that, predicting the strains that must be included in the formulation of vaccines for combating upcoming influenza outbreaks is difficult owing to gene mutations through antigenic drift and shift patterns in influenza viruses [4]
The idea of incorporating a number of conserved influenza peptides, especially those derived from internal viral antigens in a single universal influenza vaccine formulation, has been endeavoured in the studies described in this review

Summary

Introduction

Influenza is an acute respiratory infection caused by influenza viruses. The World Health Organization (WHO) estimates that 3–5 million cases of influenza occur each year and the infection accounts for 250,000–500,000 deaths worldwide [1]. Despite the pending clinical findings of the phase IIb trial, FLU-v is believed to be a potential universal influenza vaccine because it induces a higher frequency of cellular responses than natural infections This characteristic is mostly attributable to the presence of T cell epitopes derived from influenza internal antigens in FLU-v peptide vaccine formulation [27]. The idea of incorporating a number of conserved influenza peptides, especially those derived from internal viral antigens in a single universal influenza vaccine formulation, has been endeavoured in the studies described in this review These vaccine candidates are expected to confer long-term memory immunity against subsequent influenza virus infections. In the preparation of MVA smallpox vaccine in the United States, approximately 20 million doses of MVA smallpox vaccine were produced [56], which is beneficial for the mass production of influenza vaccines to counter the upcoming influenza outbreaks

Conclusion

Conflict of Interest