Advax augments B and T cell responses upon influenza vaccination via the respiratory tract and enables complete protection of mice against lethal influenza virus challenge

Jasmine Tomar,Harshad P Patil,Gustavo Bracho,Wouter F Tonnis,Henderik W Frijlink,Nikolai Petrovsky,Rita Vanbever,Anke Huckriede,Wouter L.J Hinrichs

doi:10.1016/j.jconrel.2018.09.006

Abstract

Administration of influenza vaccines via the respiratory tract has potential benefits over conventional parenteral administration, inducing immunity directly at the site of influenza exposure as well as being needle free. In this study, we investigated the suitability of Advax™, a stable particulate polymorph of inulin, also referred to as delta inulin, as a mucosal adjuvant for whole inactivated influenza vaccine (WIV) administered either as a liquid or dry powder formulation. Spray freeze-drying produced Advax-adjuvanted WIV powder particles in a size range (1–5 μm) suitable for inhalation. The physical and biological characteristics of both WIV and Advax remained unaltered both by admixing WIV with Advax and by spray freeze drying. Upon intranasal or pulmonary immunization, both liquid and dry powder formulations containing Advax induced significantly higher systemic, mucosal and cellular immune responses than non-adjuvanted WIV formulations. Furthermore, pulmonary immunization with Advax-adjuvanted WIV led to robust memory B cell responses along with an increase of lung localization factors i.e. CXCR3, CD69, and CD103. A less pronounced but still positive effect of Advax was seen on memory T cell responses. In contrast to animals immunized with WIV alone, all animals pulmonary immunized with a single dose of Advax-adjuvanted WIV were fully protected with no visible clinical symptoms against a lethal dose of influenza virus. These data confirm that Advax is a potent mucosal adjuvant that boosts vaccine-induced humoral and cellular immune responses both in the lung and systemically with major positive effects on B-cell memory and complete protection against live virus. Hence, respiratory tract immunization, particularly via the lungs, with Advax-adjuvanted WIV formulation as a liquid or dry powder is a promising alternative to parenteral influenza vaccination.

Highlights

Influenza is a highly contagious disease affecting millions of people worldwide on annual basis [1,2]
For the use of Advax as a mucosal adjuvant for whole inactivated influenza vaccine (WIV), it is essential that it has no detrimental effects on the physical and biological properties of inactivated virus particles; and that Spray-freeze drying (SFD) has no impact on the physical characteristics of Advax
We demonstrate that administration of Advaxadjuvanted WIV to the respiratory tract, either as liquid or dry powder, has the potential to boost influenza induced systemic, mucosal and cellular immune responses

Summary

Introduction

Influenza is a highly contagious disease affecting millions of people worldwide on annual basis [1,2]. Since the respiratory tract is the portal of influenza virus entry, in-theory the best means of protection would be to use a vaccine to generate a local memory immune response able to neutralize the virus at the site of infection. The majority of the currently available influenza vaccines are administered via intramuscular or subcutaneous injection [5]. Injected vaccines generate strong systemic immunity but minimal mucosal immunity [6,7]. Injected vaccines can cause local reactions including pain, swelling and redness at the injection site, needle phobia, and transmission of infectious diseases due to needle stick injuries. An influenza vaccine formulation that could be administered via the respiratory tract would overcome these drawbacks of current injected formulations, is needed

Methods

Results

Conclusion