The study showed that the orally delivered ORT-VAC™ DNA vaccine produced higher immune responses in mice than the injected DNA vaccine. This resulted in a reduction in the lungs of the TB bacterium Mycobacterium tuberculosis in immunised mice. Previous studies using ORT-VAC™ to deliver protein vaccines have protected against bubonic plague and anthrax in mice.
RecipharmCobra’s vaccine delivery technology ORT-VAC™ employs live Salmonella bacteria to deliver a TB vaccine orally. The Salmonella bacteria have been modified so that they do not cause disease. The vaccine is a DNA vaccine, a relatively new vaccine approach where a gene from a disease-causing microorganism is used to stimulate an immune response.
ORT-VAC™ stabilises plasmids without the need for antibiotics, so no antibiotic resistance genes are present on the plasmid. This also reduces the potential transfer risk to pathogens, which could result in the generation of antibiotic-resistant ‘superbugs’.
Simon Saxby, VP of Biologics at RecipharmCobra Biologics, said: “Using an attenuated bacterium to deliver vaccines orally is a very exciting new area, and the delivery of DNA vaccines has been particularly challenging. The study illustrates the versatility of RecipharmCobra’s ORT-VAC™ technology to provide a delivery route for needle-free administration of a DNA vaccine. A vaccine based on ORT-VAC™ could be inexpensive to produce, simple to distribute and easy to administer, which is essential for tackling the disease in developing countries".