Innovative strategy to make Malaria Vaccine more effective

An innovative system for delivering a malaria vaccine has been developed by researchers at the Institute for Molecular Engineering at the University of Chicago that shows promise in its effectiveness. By developing a vaccine that targets specific cells in the immune system, they have seen a much greater immune and antibody response to the vaccine. This work could potentially have applications in vaccinations against complex infections and cancer.

The discovery has appeared in form of a paper that was recently published in Nature Materials.

The avalable vaccine for malaria is only effective in 30 per cent to 50 per cent of patients, and malaria is still responsible for nearly 500,000 deaths annually, according to the Centers for Disease Control. Developing new vaccines is a challenge as they require both protection against pathogens and specialized immune cells to clear infected cells. But immunoengineering is a speciality of the IME, which is helping shape the emerging field of molecular engineering to address global challenges from the molecular level up.

“When compared to the current malaria vaccine option, our results are extremely exciting,” said Jeffrey Hubbell, Eugene Bell Professor in Tissue Engineering and corresponding author on the paper. “This work could potentially have applications in vaccinations against complex infections and cancer.”

The researchers have developed several strategies for generating immunity in patients. One of the safest and easiest vaccine platforms is the subunit vaccine. Researchers take proteins derived from the pathogen, called antigens, and formulate them with a compound called an adjuvant that induces a pro-inflammatory response. In the body, the antigen introduces the disease to the immune system, while the adjuvant activates pathogen-specific T cells, which help clear infected cells. This type of vaccine is used for whooping cough, HPV and malaria.

While the field has developed subunit vaccines with effective antigens, researchers have found less success with adjuvants, mainly because it is difficult to localize their delivery to the right location within the body. If such molecules aren’t targeted, they can cause inflammation throughout the body, which can be fatal.

Hubbell and his colleagues approached this problem as a delivery issue. To deliver the vaccine to its intended target, they developed a vaccine platform made up of a polymeric adjuvant and in order to make sure it found its way to the intended site, they incorporated mannose, a type of sugar, into the polymeric adjuvant. Because viruses and bacteria tend to have a lot of sugar on their surfaces, the dendritic cells in the lymphoid tissues have several sugar receptors that help in the recognition of pathogens.

So once the mannose-laden vaccine is injected into the body, it targets specific immune cells called dendritic cells, which in turn activate T cells. By specifically targeting dendritic cells, this new technology prevents systemic inflammation while efficiently activating an immune response.

When tested, the vaccine system had a higher antibody response than the malaria vaccine currently on the market. It also provided a cellular response—clearing the infected cells—which the current vaccine does not do.