Engineered polypeptides for enhanced integrin binding and antigen delivery

Engineered recombinant Invasin polypeptides have been modified to enhance integrin binding and resist intestinal proteolysis, facilitating effective oral delivery of therapeutics, such as vaccines, by targeting M cells in the gut for improved immune responses.

Background

The challenge of delivering therapeutics such as vaccines effectively across biological barriers, such as the intestinal epithelium, has been a significant challenge. Using traditional methods, large molecules cannot traverse the gut lining efficiently, leading to reduced bioavailability and therapeutic efficacy. Approaches using nanoparticles, liposomes, or chemical enhancers have shown promise but suffer from limited targeting specificity, potential toxicity, and complex manufacturing processes. Delivery systems also need to ensure that the therapeutic agents remain stable and active until they reach their intended site of action. By engineering polypeptides to have higher binding affinities and resistance to degradation, there can be more robust and effective therapeutic delivery mechanisms.

One area of study is enhancing the binding affinity of polypeptides to integrins, which are proteins that facilitate cell adhesion and signal transduction. But current approaches using polypeptides face several challenges. Use of wild-type polypeptides often exhibit limited binding affinity to integrins, which can result in inefficient delivery of the therapeutic agents to target cells.

Additionally, these polypeptides are susceptible to proteolysis by intestinal enzymes, reducing their effectiveness when administered orally. The low transit efficiency through the gastrointestinal tract further complicates the use of these molecules in clinical settings. Moreover, the existing polypeptides may not adequately target specific cell types, such as M cells in the gut, crucial for initiating immune responses. These limitations need engineered polypeptides with enhanced binding characteristics and stability to improve therapeutic outcomes.

Technology description

Recombinant high-affinity Invasin polypeptides have been engineered to enhance their ability to bind integrins and facilitate delivery of therapeutics, such as vaccines. These polypeptides include modifications in a key domain—specifically, amino acid substitutions at certain positions forming a motif known to increase integrin binding affinity. Additionally, another domain may also be modified with substitutions at other key positions to further improve binding characteristics. The polypeptides can be conjugated to therapeutic agents, including immunogenic compositions, to enhance their delivery across the gastrointestinal membrane or to other target cells. These engineered Invasin variants are resistant to proteolysis by intestinal enzymes, making them suitable for oral administration and effective in targeting specific cells in the gut for improved immune responses against various diseases.

This technology is differentiated by its ability to significantly enhance the binding affinity of Invasin polypeptides to integrins, which is achieved through specific amino acid substitutions that form a motif. This motif is known to increase integrin binding affinity by up to 1,000-fold compared to wild-type Invasin. The modifications in the two other domains not only improve binding characteristics, but also ensure that the polypeptides are resistant to proteolysis by intestinal enzymes, making them viable for oral delivery. The ability to conjugate these polypeptides to therapeutic agents, such as vaccines, allows for targeted delivery to specific cells in the gut, thereby enhancing immune responses. This makes the technology particularly valuable for developing oral vaccines and other therapeutic agents that require efficient delivery across the gastrointestinal membrane.

Benefits