Team:HZAU-China/Project/Bacterial Spores as Vaccine Vehicles

• Overview
• The innovation of HZAU-iGEM Team
• The design of experiment
• Rabies
• Flea and Yersinia pestis
• Bacterial Spores as Vaccine Vehicles
• Bacillus subtilis as Probiotics
• Antimicrobial Peptides
• Methods for rearing flea

Bacillus subtilis has been explored as a host for the expression of foreign genes with immunological activities. The following are main reasons:

1.As gram-positive bacteria, B.subtilis strains do not have an outer membrane, which is appropriate for secreting proteins directly into medium.

2.Similar to Ecolic and Yeast, the genetic knowledge and gene expression systems of B.subtilis strains are easier to get.

3.B.subtilis has received the GRAS(generally regarded as safe) status.

4.B.subtilis spores is the most resistant life form on earth and can exist under extreme environmental conditions , which makes the spore an attractive vector for delivering antigens. Meanwhile, B.subtilis spores is effective for oral antigen and can active mucosal immune response.

5.Non-biased codon usage and simply cultivate conditions make it a good candidate for the expression of heterologous proteins.

The potential advantages for B.subitilis as vaccine vector.

They are two ways for using B.subtilis as vaccine delivery vectors. One is the use of genetically modified B.subtilis spores expressing surface-exposed antigens fused to spore coat proteins. Another is focused on the production of recombinant antigens, which dependents on germinating spores.

The table shows some examples of vaccine application in humans.

In our experiment design, we choose the second one. Germinating spores can secrete antigen to host to induce immunity response.