Therapeutic fusion Protein Platform In humans, signaling molecules are the basic mechanism that underlie the ability of cells to precisely respond to a changing microenvironment. They tightly regulate many biological processes including development, tissue repair, immunity, and tissue homeostasis. Errors in these signaling processes may cause diseases such as cancer, autoimmune diseases, diabetes, etc.

However, many of the signaling molecules have a built-in property of fast-decay. For example, almost all cytokines have a molecular weight less than 25KD, which are rapidly cleared out of the body through renal filtration. Therefore, many signaling molecules in their native forms cannot be used effectively as therapeutic agents. Several different technologies have been developed to extend the half life of signaling molecules. Fusion with Fc domain can significantly increase the half life of a signaling molecule. However, Fc- fusion proteins often need to be expressed in mammalian cells, which has a long development cycle and a high production cost. Signaling molecules expressed in a mammalian host often have low yields, possibly due to the toxicity to the host cells. Human serum albumin (HSA) is also used to make fusion proteins of signaling molecules expressed in yeast, but HSA- fusion proteins expressed in yeast often contain non-human glycosylation. Yeast proteases can also cause product degradation, which generates serious purification and quality control issues. PEG conjugation is another widely used method, but PEG conjugation can lead to a large loss of biological activity. Additionally, the complex mixture of the conjugation products makes the purification and quality control very challenging.

ProtTech has developed a novel fusion protein platform, with a series of signaling molecule-P50 fusion proteins that have potential therapeutic use (Patent Pending). All the fusion proteins we have developed have demonstrated exceptionally high expression yields, a rapid development cycle, simple purification processes, and high biological activity. Another important application of our P50 fusion protein platform is in therapeutic Nanobodies (domain antibody). We have demonstrated in our Nanobody-P50 fusion project that a Nanobody-P50 fusion is expressed from an E.coli host at a very high level. A Nanobody-P50 fusion protein may have a much extended in vivo half life, while retaining its appealing features such as high affinity, high stability, and high tissue penetration.

Please contact us if you are interested in ProtTech’s fusion protein technology or a possible collaboration of ProtTech’s fusion protein project for therapeutic use.