Peptide-HLA-DQ8 biologics for antigen-specific therapy in Type 1 Diabetes

PROJECT SUMMARY/ABSTRACT Antiger Therapeutics Inc is a startup biotech company specializing in engineering recombinant human leukocyte antigens (HLA) and membrane proteins. In this SBIR phase I application, we leverage this expertise to develop targeted immunotherapies for type 1 diabetes (T1D), a global health challenge affecting around 8.4 million individuals. As a chronic autoimmune disease, T1D leads to severe complications like cardiovascular and kidney injuries, substantially reducing life expectancy by an average of 13 years. Current immunotherapies suppress the immune system in a nonselective manner, and the associated toxicity precludes their long-term use for T1D control. The sole FDA-approved immunotherapy for T1D, teplizumab, only delays the disease onset for approximately two years. Antiger Therapeutics Inc aims to address this problem by selectively targeting the abberrant immune response in T1D. One pivotal immunogenetic factor in T1D development is the HLA-DQ8 membrane protein, which presents autoantigens such as insulin peptides to activate pathogenic T cells and disrupt immune tolerance. Our primary objective is to specifically block the pathogenic T cells that recognize the insulin peptide-DQ8 (pDQ8) complex, thereby safely preventing or reversing T1D. Antiger's proposed product is an innovative biologic comprised of functional multimers of pDQ8. However, assembling the pDQ8 complex poses technical challenges due to inefficient pairing between DQα and DQβ chains. To overcome this problem, the company employs novel solutions involving disulfide bond engineering and the production of full-length membrane proteins. Antiger's recent work has demonstrated the effectiveness of disulfide engineering in producing functional, dimeric pDQ7-Fc at increased yields. Through structural modeling, conserved regions in DQ7 and DQ8 were identified with the potential for disulfide bond engineering to improve complex assembly and production yield. In Specific Aim 1, we will generate dimeric pDQ8-Fc fusion proteins. The pDQ8 complex will be stabilized by inter-chain disulfide bond introduced by site-directed mutagenesis to enhance the production yield; the Fc portion enables dimerization of the pDQ8 complex in an antibody-like structure. In Specific Aim 2, we will generate pDQ8-Transmembrane proteins on detergent micelles. The transmembrane domains of full-length α and β chains of DQ8 protein will promote the assembly of pDQ8 complex to be solubilized on micelles. In both aims, we will assess the yield and purity of multimeric pDQ8 proteins and measure their inhibitory effect on pDQ8-specific T cell hybridomas. By the end of this phase I SBIR, we expect to generate one or more candidate proteins that meet pre-specified acceptance criteria on production yield, purity, and function. Phase II plans encompass testing the biologic in humanized murine T1D models, assessing immunogenicity and optimization, ultimately preparing for IND submission. Commercially, Antiger intends to collaborate with or license the product to a pharmaceutical company for further development, aiming to tap into the high-demand T1D therapeutic market, projected to be worth $24 billion by 2029. Moreover, the scalable technology holds promise for addressing other class II HLA-associated autoimmune disorders, such as celiac disease and rheumatoid arthritis.