Spy Catcher and Snoop Catcher: A Revolutionary Approach to Protein Ligation for Vaccine Development

In recent years, protein ligation has emerged as a crucial technique in the development of vaccines and therapeutic agents. The membrane environment plays a significant role in protein ligation, and researchers have made significant progress in understanding its mechanisms. In this article, we will explore the application of Spy Catcher/SpyTag protein ligation technology to enzymatically link antigens to Hbp present at high density in outer membrane vesicles (OMVs).

The autotransporter Hbp has been engineered into a surface display system that can be expressed to high density on live Escherichia coli cells. However, its capacity with respect to the number, size, and structural complexity of antigens genetically fused to the Hbp carrier is restricted. To address this limitation, researchers have developed a semisynthetic OMV platform for recombinant antigen presentation on OMVs derived from attenuated Salmonella enterica serovar Typhimurium cells displaying an adapted Escherichia coli autotransporter, Hbp, at the surface.

The Spy Catcher/SpyTag protein ligation system has been shown to be effective in linking antigens to Hbp present at high density in OMVs. Additionally, nanobodies have also been found suitable for Spy-mediated ligation. Moreover, the orthogonal SnoopTag/SnoopCatcher system allows multiple antigen modules to be coupled to Hbp in a sequential ligation strategy.

The benefits of using Spy Catcher and Snoop Catcher protein ligation technology are numerous. For instance, it enables the targeting of live bacterial or OMV vaccines to certain tissues or immune cells, allowing for tailoring of immune responses. Furthermore, the system allows for efficient covalent coupling of purified proteins fused to the SpyTag domain to Hbp-SpyTag.

In conclusion, Spy Catcher and Snoop Catcher protein ligation technology has the potential to revolutionize vaccine development by enabling the efficient presentation of antigens on OMVs derived from Gram-negative bacteria. Its applications are vast, ranging from vaccine development to therapeutic agent delivery. With its ability to target specific tissues or immune cells, it offers a promising approach for tailoring immune responses and improving vaccine efficacy.

Spy catcher and snoop catcher