A strain of chlamydia has led to a significant reduction in Australia's koala population.

Chlamydia antigens produced through a hyper-targeted method by scientists from Lawrence Livermore National Laboratory and the biotech company Synthetic Genomics could pave the way toward a vaccine for the most-common sexually-transmitted disease.

The method of creating major outer membrane proteins, or MOMPs, could provide immunity against the bacteria that infects 1.5 million people in the United States each year, and 100 million worldwide, the team writes in the Journal of Biochemistry. It could even be used for the direct creation of other antigens, they add.

“Our cell-free expression approach, coupled with the (molecular) assembly, provides a robust model system for expressing difficult-to-obtain target membrane proteins amenable for formulation in the next generation of multivalent subunit vaccines,” they write.

Inactivated chlamydia germs have been used as a vaccine candidate – but the protection only lasts a short time.

The target antigen MOMPs have previously proven to be grown in E. coli cells. But that technique required some additional genetic manipulation – and it also takes a significant amount of time.

Instead, the Lawrence Livermore and Synthetic Genomics personnel nanolipoprotein particules with telodendrimer additives to generate more of the proteins – and more accurate proteins with the proper folding and dimensions, they report.

The enriched ribosomes and translational machinery that were at play in the E. coli cells were thus essentially extracted, and then supplemented with RNA polymerase and brought together in a unique mix.

Because there are no living cells present – and toxicity thresholds are not a concern – more antigen can be made in a short amount of time.

“With this paper, we’ve shown that it is possible to take a potentially therapeutic protein that has a very complex structure and recreate it starting with some simple biological components, which is a promising development in this field,” said Matt Coleman, the senior author of the paper.

The development is moving ahead with rodent trials. Another application of the antigen could be in Australia’s koala population, which has been significantly reduced due to a strain of chlamydia.

The scientists said the concept of mixing together constituent parts for target antigens could even potentially be translated to cancer immunotherapies.

Synthetic Genomics, founded and headed by J. Craig Venter in 2005, has published some recent breakthroughs. Jointly with ExxonMobil in June they announced a potential breakthrough in producing a kind of oil from algae.