Current Research in Faculty of Agriculture

Silkworms as a protein production factory.

Prof. Kusakabe in the Faculty of Agriculture at Kyushu University has succeeded in developing protein producing technology in silkworms to meet the increasing demand for large quantities of high-quality recombinant proteins for medical and veterinary applications. Silkworms are suitable for mass production of recombinant proteins since their cultivation is well established and they are easy to breed on a large scale even in a small room, which also ensures that the genetically modified insects cannot escape. This newly developed method uses the silkworm body as a protein production factory. The gene encoding the target protein is introduced into the genome of a disabled virus that infects only silkworms but does not cause disease. The virus replicates inside the body of the silkworm producing the target protein.

Kyushu University has a long history as a center for sericulture research, which studies the cultivation of silkworms for production of the protein used to produce silk, and has established a world-class collection of 450 silkworm strains for both commercial sericulture and scientific research. Prof. Kusakabe used this collection to select one strain that is susceptible to viral infection. This strain is a genetically pure system, which means that we can expect the same efficiency of protein production without variation for many years.

This new technology allows mass production at low cost even of recombinant proteins that are hard to express in bacteria or culture cell lines, and was commercialized by KAIKO Ltd as a Kyushu University venture in 2018. Kaiko Ltd produces proteins as medicines for pets and for use as oral animal vaccines. Recently they succeeded in the production of the spike-like surface protein of the SARS-CoV-2 virus, a vaccine candidate for COVID-19. Perhaps in future the technology will be developed further to create low-cost vaccines for COVID-19 and other diseases that can be eaten.
(read more about this topic and other Kyushu University research in the latest edition of CONNECT)