Conserved peptides enhance immune efficiency of inactive vaccines against emerging avian influenza viruses in chicken

Abstract

Avian influenza viruses (AIVs) such as H5N1 and H7N9 are a great threat to poultry economics and public health. Vaccination can effectively inhibit the spread of AIV in poultry, which is also a viable strategy for controlling virus transmission from poultry to human. Adjuvants that are commonly used in current inactivated vaccines to provide stronger anti-AIV immune responses are often limited in their capacity to quantitatively induce both humoral and cellular immune responses. Herein, we assessed the levels of immune responses generated by a vaccine formulation comprising inactivated H5N1 antigen and synthetic peptides covering conserved CD4, CD8 T cell, and B cell epitopes. We found that the synthetic peptides enhanced the antibody responses against conserved influenza virus antigen M2e. Notably, the hemagglutination inhibition test results indicated that the peptides significantly augmented the antibody responses of inactivated H5N1 antigen even in the 1/10 or 1/5 dose group, in the identical antibody level as antigen alone used at the full dose. This indicates that the peptide can significantly reduce the use of inactivated virus, lowering the cost of the vaccine. Moreover, the peptides increased the transcript levels of interleukin-4 and interferon-γ cytokines in chicken peripheral blood mononuclear cells, which may facilitate both humoral and cellular immune responses. Our data suggest that this peptide combined with inactivated H5N1 antigen enhances both the humoral and cellular immune responses, which may benefit the prediction and design of synthetic peptide-based adjuvants for vaccines in chicken.

Induction of cross-reactive antibodies in mice immunized with conserved influenza A virus neuraminidase-derived linear B-cell epitopes

“…С одной стороны, улучшить эффективность вакцинации можно за счет регламентирования минимального содержания NA в противогриппозных вакцинах [10,16]. С другой стороны, консервативные эпитопы NA можно использовать при конструировании универсальной гриппозной вакцины [18,20], а также в качестве дополнительного компонента к уже имеющимся вакцинам [34,38]. В последние годы ведется активная работа по поиску моноклональных антител к ферментативному сайту NA, обладающих широкой кросс-реактивностью в отношении вирусов гриппа А различных подтипов, а также вирусов гриппа типа В [35].…”

The Immunological Basis for Vaccination

“…Recent immunoinformatic-based reverse vaccinology approaches allowed the identification of not only specific B-cell but also T-cell epitopes, and allowed the induction of predicted antibodies for example against IBDV using a designed multiepitope vaccine construct (136). The combination of an inactivated full-antigen vaccine against H5N1 AIV in combination with selected conserved synthetic peptides was shown to stimulate T and B cells and augmented the enhancement of protection (137).…”

On the Centenary of the Spanish Flu: Being Prepared for the Next Pandemic

“…Furthermore, given the substantial lead time and the lack of available vaccines ahead of any unpredictable pandemic, major efforts are needed to develop new universal vaccines that stimulate broadly reactive antibodies or T-cells against conserved epitopes to confer heterotypic protection against different subtypes of influenza viruses, or at least one subtype in humans or poultries (Xiao et al . 2017 ; Zhao et al . 2018 ).…”