High-Titer Neutralizing Antibodies against the SARS-CoV-2 Delta Variant Induced by Alhydroxyquim-II-Adjuvanted Trimeric Spike Antigens

Abstract

There is an urgent need for next-generation COVID-19 vaccines that are safe, demonstrate high protective efficacy against SARS-CoV-2 variants and can be manufactured at scale. We describe a vaccine candidate (CoVac-II) that is based on stabilized, trimeric spike antigen produced in an optimized, scalable and chemically defined production process.

Clinical development of SpikoGen®, an Advax-CpG55.2 adjuvanted recombinant spike protein vaccine

“…In recent years, multiple new adjuvants have been introduced alongside existing aluminum salt and oil emulsion adjuvants. 21 New adjuvants include ISS1018, a toll-like receptor (TLR)-9 agonist in Heplisav® hepatitis B vaccine, 22 Matrix M, a saponin-based adjuvant in Nuvaxoid COVID-19 vaccine, 23 the alum-CpG adjuvant in Corbevax® RBD vaccine, 24 Alhydroxyquim adjuvant in Bharat biotech’s inactivated COVID-19 vaccine approved in India, 25 ASO1B, an adjuvant containing a liposomal mixture of QS21 and monophosphoryl lipid A (MPL) in Shingrix® shingles vaccine 26 and Mosquirix® malaria vaccine, 27 AS04, an adjuvant comprising MPL absorbed to aluminum phosphate in Fendrix® hepatitis B vaccine, 28 and Vaxine’s own Advax-CpG55.2 adjuvant in SpikoGen® vaccine.…”

An Overview of the Conventional and Novel Methods Employed for SARS-CoV-2 Neutralizing Antibody Measurement

“…The immunity generated by natural infection and vaccination are effective ways to reduce the risk of clinically severe outcomes [ 6 , 7 ]. In both scenarios, the production of neutralizing antibodies (NAbs) is considered a determinant factor for predicting protective immunity against SARS-CoV-2 [ 8 , 9 ]. Indeed, preclinical studies using NAbs as a treatment for SARS-CoV-2 infection in rhesus macaques and hamster models have shown marked reductions in viral loads in the upper and lower respiratory tracts, and also a decrease in virus-induced pathological sequelae [ 10 ].…”

Affordable SARS-CoV-2 protein vaccines for the pandemic endgame

“…Because of their lack of complexity, these vaccines can be manufactured cost-effectively in commonly available biotechnology facilities. Like mRNA vaccines, protein vaccines can also be rapidly deployed to target new viral variants 7 . In addition, protein subunit vaccines can be stored and transported at ambient temperature and can induce long-lasting immunity 6 .…”