A Convenient Synthetic Method to Improve Immunogenicity of Mycobacterium tuberculosis Related T-Cell Epitope Peptides.

Judit Henczkó,Beáta Biri-Kovács,Kata Horváti,Eleonóra Szabó,Kinga Fodor,Viktor Farkas,Bálint Szeder,Gyula Balka,Bernadett Pályi

doi:10.3390/vaccines7030101

Abstract

Epitopes from different proteins expressed by Mycobacterium tuberculosis (Rv1886c, Rv0341, Rv3873) were selected based on previously reported antigenic properties. Relatively short linear T-cell epitope peptides generally have unordered structure, limited immunogenicity, and low in vivo stability. Therefore, they rely on proper formulation and on the addition of adjuvants. Here we report a convenient synthetic route to induce a more potent immune response by the formation of a trivalent conjugate in spatial arrangement. Chemical and structural characterization of the vaccine conjugates was followed by the study of cellular uptake and localization. Immune response was assayed by the measurement of splenocyte proliferation and cytokine production, while vaccine efficacy was studied in a murine model of tuberculosis. The conjugate showed higher tendency to fold and increased internalization rate into professional antigen presenting cells compared to free epitopes. Cellular uptake was further improved by the incorporation of a palmitoyl group to the conjugate and the resulted pal-A(P)I derivative possessed an internalization rate 10 times higher than the free epitope peptides. Vaccination of CB6F1 mice with free peptides resulted in low T-cell response. In contrast, significantly higher T-cell proliferation with prominent expression of IFN-γ, IL-2, and IL-10 cytokines was measured for the palmitoylated conjugate. Furthermore, the pal-A(P)I conjugate showed relevant vaccine efficacy against Mycobacterium tuberculosis infection.

Highlights

Vaccination with whole pathogens elicits long-lasting immunity and robust immune response.immunization with subunit vaccines using purified and specific antigens became an attractive alternative because of manufacturing, safety, and stability considerations
The aim of of this study was to provideSynthetic a simple long synthetic route to improve the immunogenicity vaccine efficacy
Synthetic long peptides havedesign proven clinical but the production of of long linear peptides is still challenging in most cases.(SLPs)

Summary

Introduction

Vaccination with whole pathogens elicits long-lasting immunity and robust immune response.immunization with subunit vaccines using purified and specific antigens became an attractive alternative because of manufacturing, safety, and stability considerations. Epitopes are minimal antigenic determinants of proteins They have the capacity to activate B- and T-cells and elicit humoral and/or cellular immune response against the target pathogen. We need to deal with disadvantages such as the fast in-vivo degradation, low systemic stability, lack of tissue-specific penetration, loss of native conformation, and low immunogenicity. Despite these generic disadvantages, there are approximately 140 peptide therapeutics being evaluated in clinical trials [3]. Peptide synthetic and conjugation techniques give us a tool to combine different epitope peptides in one compound that can reflect the antigen diversity of a pathogen [6]

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