Vaccinations have nearly wiped out many serious infectious diseases, substantially improving public health. To design a vaccine, antigens need to be identified and isolated. The antigens are then delivered to the body, setting off an immune response and causing the body to create the necessary antibodies. In a study recently published in the journal Science Advances, scientists have come up with a new way to deliver these antigens to the body. They designed a capsule utilizing harmless bacteria to transport the antigens. This biological delivery system was found to be more efficient and very effective against pneumococcal disease.
While the name E. coli tends to scare people, this negative reputation is largely undeserved. Most strains of Escherichia coli are harmless and naturally occur in the body. The researchers chose one of these nonpathogenic strains and used it as the basis for a new vaccine delivery system. Strains like the one chosen can be modified, using a variety of biochemical methods, to produce certain proteins including antigens. The bacterial capsule was wrapped in a special polymer and then injected with a dose of a vaccine. The vaccine selected for use in the study is effective against pneumococcal disease, an infectious disease caused by Streptococcus pneumoniae bacteria. Infections lead to pneumonia and are especially dangerous to children and seniors. When tested with mice, the researchers found that this new type of delivery capsule was very effective against S. pneumoniae. Their results showed that their transportation method was more efficient than traditional vaccines.
The biological capsule method allowed the antigens to easily get to the proper parts of the body. The bacteria have natural adjuvant properties, allowing for better immune system responses. These properties eliminate the need for standard vaccine components such as aluminum. This new method also allows for antigen production to occur when the vaccine has already been delivered to the body. Antigens would no longer have to be isolated and purified in a separate process. Finally, modifications to the bacteria allow the vaccine to target specific cells, further increasing the effectiveness of the immunization.
These new findings can be used to develop more efficient vaccines. The methods used in the study are not expensive to reproduce, making this a practical alternative to traditional vaccine techniques. The authors also believe that their findings could be used to develop more effective cancer treatments.
Yi Li et al. In situ pneumococcal vaccine production and delivery through a hybrid biological-biomaterial vector. Science Advances (2016).