Conserved Influenza Hemagglutinin, Neuraminidase and Matrix Peptides Adjuvanted with ALFQ Induce Broadly Neutralizing Antibodies

Abstract

A universal influenza candidate vaccine that targets multiple conserved influenza virus epitopes from hemagglutinin (HA), neuraminidase (NA) and matrix (M2e) proteins was combined with the potent Army liposomal adjuvant (ALFQ) to promote induction of broad immunity to seasonal and pandemic influenza strains. The unconjugated and CRM-conjugated composite peptides formulated with ALFQ were highly immunogenic and induced both humoral and cellular immune responses in mice. Broadly reactive serum antibodies were induced across various IgG isotypes. Mice immunized with the unconjugated composite peptide developed antibody responses earlier than mice immunized with conjugated peptides, and the IgG antibodies were broadly reactive and neutralizing across Groups 1 and 2 influenza viruses. Multi-epitope unconjugated influenza composite peptides formulated with ALFQ provide a novel strategy for the development of a universal influenza vaccine. These synthetic peptide vaccines avoid the pitfalls of egg-produced influenza vaccines and production can be scaled up rapidly and economically.

Unconjugated Multi-Epitope Peptides Adjuvanted with ALFQ Induce Durable and Broadly Reactive Antibodies to Human and Avian Influenza Viruses

“…The composite influenza peptides (referred to in this article as LHNVD-105) was used for mice immunization studies. LHNVD-105 has previously been described in detail [ 14 ]. It comprised two composite influenza peptides, HA + NA (Flu Pep11) and Matrix (M1/M2/M2e) + T-cell epitope (Flu Pep5906), adjuvanted with ALFQ.…”

“…Synthetic, multi-epitope peptide vaccines that offer rapid and cost-effective advantages in scaling-up for clinical trials are rapidly gaining prominence as a universal influenza vaccine strategy [ 5 ]. A potential disadvantage of small peptide vaccines is their lack of immunogenicity, which can be circumvented via conjugation with immunogenic carrier molecules such as the mutated diphtheria toxin CRM197, or through formulation with safe and highly potent adjuvants such as the liposome-based ALFQ adjuvant, as well as the incorporation of universal T-cell epitopes in the peptide sequence for intrinsic immune-stimulation [ 14 , 15 , 16 , 17 , 18 ].…”

“…Previously, we demonstrated that 1 µg of an unconjugated peptide vaccine consisting of highly conserved composite HA, NA, Matrix (M1/M2/M2e) epitopes and a tetanus toxoid T-cell epitope formulated with Army Liposome Formulation with QS-21 (ALFQ) adjuvant elicited robust immune responses in mice when administered via an intramuscular route [ 14 ]. Here, we demonstrate that this influenza vaccine generated durable and broadly reactive antibodies in outbred mice at a low dose (1 µg) and a high dose (20 µg) administered intramuscularly and intradermally.…”

Similarities and differences of chemical compositions and physical and functional properties of adjuvant system 01 and army liposome formulation with QS21

“…The invention and patenting of Army Liposome Formulation with QS21 (ALFQ) ( 15 ) has enabled the testing of numerous different completed, ongoing, or projected human trials utilizing ALFQ as the vaccine adjuvant ( 16 ). Seven current ongoing or planned vaccine trials containing ALFQ as an adjuvant include two different vaccines to Plasmodium falciparum malaria ( 17 – 19 ), two different HIV-1 vaccines ( 20 , 21 ), a vaccine to traveler’s diarrhea caused by Campylobacter jejuni ( 22 ), a vaccine to SARS-CoV-2 which targets multiple variants to prevent COVID-19 ( 23 ), and a phase 1 trial which is planned to test a universal influenza vaccine candidate utilizing unconjugated peptides as antigens ( 24 ).…”

Bacteriophage T4 Vaccine Platform for Next-Generation Influenza Vaccine Development

“…Engineered headless HA stalk, in which the immunodominant head domain was removed, was mainly used to induce antibodies that recognize or neutralize diverse influenza virus strains (18,19). Another widely used target for universal Flu vaccines is the extracellular domain of matrix protein 2 (M2e) that is highly conserved among divergent influenza virus strains (14,20,21). However, none of these vaccine targets are highly immunogenic and many strategies were employed to enhance their immunogenicity (22)(23)(24)(25).…”