Discovery of group a streptococcus antigens for development of broadly effective vaccine candidates to prevent non-invasive and invasive disease and emergence of antimicrobial resistance -…

The National Institute of Allergy and Infectious Diseases awarded $300,000 to Immport Therapeutics Inc. (doing business as Antigen Discovery Inc.) on August 26, 2026, under the Allergy and Infectious Diseases Research program (CFDA 93.855) to discover Group A Streptococcus antigens for development of broadly effective vaccine candidates.

The project focuses on identifying vaccine candidates that prevent both non-invasive GAS infections such as pharyngitis and pyoderma and invasive disease including necrotizing skin and soft tissue infection and toxic shock syndrome. The work addresses the urgent need for a GAS vaccine as scarlet fever and invasive GAS disease have risen following the SARS-CoV-2 pandemic, particularly in low- and middle-income countries bearing the greatest disease burden. The research will use pangenomic protein microarray technology to screen the S. pyogenes proteome for vaccine antigens, expanding beyond the small selection of proteins that prior vaccine development efforts have focused on.

Immport Therapeutics specializes in protein microarray technology for infectious disease research and has prior federal grant experience in vaccine and diagnostic development across multiple infectious diseases. Performance occurs in Irvine, California, with work scheduled through July 31, 2028.

Discovery of group a streptococcus antigens for development of broadly effective vaccine candidates to prevent non-invasive and invasive disease and emergence of antimicrobial resistance - streptococcus pyogenes is a gram-positive extracellular bacterium (group a streptococcus, or "gas") that is exclusively pathogenic in humans and can cause non-invasive infections such as pharyngitis, tonsillitis, impetigo, and pyoderma, as well as outbreaks of scarlet fever. This can advance to invasive gas infections that occult blood stream infections, pneumonia, necrotizing skin and soft tissue infection, myositis, and puerperal sepsis, all of which can be complicated by streptococcal toxic shock syndrome. Non-invasive gas infections such as pharyngitis and pyoderma are associated with a concomitant high prevalence of auto-immune sequelae such as acute rheumatic fever which can lead to rheumatic heart disease. Gas causes significant morbidity, mortality and socioeconomic costs globally, with low- and middle-income countries (lmic) bearing the greatest burden. A broadly effective vaccine against non-invasive forms of infection would theoretically reduce or even eradicate all types of gas disease, including rheumatic fever and invasive infection. There is currently an urgent need for a gas vaccine, as health authorities are on alert in multiple countries about scarlet fever and invasive gas disease on the rise following the sars-COV-2 pandemic. A gas vaccine is possible, as evidenced by the acquisition of immunity to gas disease in early life and persisting until old age. Vaccine development efforts have focused on a small selection of proteins encoded by the >1,300 s. Pyogenes core genes, thus most of the s. Pyogenes genome remains unexplored for vaccine candidates. A proteome-wide screening tool such as the pangenomic protein microarray technology developed by antigen discovery, INC. (ADI) of irvine, california would be an important advance in gas vaccinology and facilitate discovery of novel vaccine candidates. ADI, in collaboration with prof. Shiranee sriskandan of imperial college london, prof. Thushan DE silva at MRC unit the gambia and members of the immunity to streptococcus pyogenes network (ispy-net), will develop and test a s. Pyogenes panproteome microarray with up to 1,000 s. Pyogenes proteins for discovery of protein targets of antibodies in young children (presumed non-immune) and adults (presumed immune) from diverse populations in the UK and the gambia, as well as in classroom cases and contacts of gas diseases. Both systemic and mucosal antibody responses will be measured in serum and gingival crevicular fluid, respectively, for IGG and IGA binding to s. Pyogenes proteins. After examining antibody profiles associated with age-related acquisition of immunity, and after excluding potential autoimmunity-inducing antigens by assessing specific gas antigen-binding antibodies on human proteome microarrays containing ~21,000 human proteins, we will develop antigen-specific functional assays to detect antibody-dependent complement activation and opsonophagocytosis based on new technology for in vitro protein expression and immobilization (ivpei) onto functionalized magnetic microspheres using ADI's expansive cell-free expression clone libraries, and we will characterize antibody function in these study samples. Our future aims for an sbir phase 2 application are to validate and further characterize antibody function in a longitudinal study of children and adults with defined gas infection status, and to establish novel vaccine candidate antigens.