A Tulane University researcher may have found a way to make an inexpensive vaccine to combat one of the world's deadliest diseases.
Dr. Nirbhay Kumar, professor and chair of tropical medicine at Tulane University School of Public Health and Tropical Medicine, has found a way to use E.coli bacteria to cheaply manufacture a once hard-to-produce protein critical to the development of a potential transmission-blocking malaria vaccine.
Kumar says malaria is one the top public health problems in the world.
"Nearly half the world's population, living in more than a hundred countries, are still at risk of malaria infections."
"The number of clinical infections adds up to more than 300 million," says Kumar. "It's a really staggering number, when you think of it."
Malaria is caused by a microscopic parasite that alternates between human and mosquito hosts at various stages of its life cycle.
Kumar, worked with the Walter Reed Army Institute for Research to use the common E.coli bacteria to create a new process to purify and refold a protein contained in the bacteria.
When tested as a vaccine, the protein produced a 100 percent effective malaria transmission-blocking antibody response in mice using the two most common species of malaria-carrying mosquitoes, according to results to be published in the April issue of the journal Infection and Immunity.
"We identified a protein molecule that's important for the parasite. And we have, basically, developed methods to produce large amounts of this protein using bacteria as a vaccine for manufacturing this protein.
"We are really fortunate to find out that the protein that these bacteria made, after modifications, were completely functional in stopping the transmission of malaria."
Kumar's vaccine seeks to trigger an immune response in people so they produce antibodies that target a protein the malaria parasite needs to reproduce within a mosquito.
He says the vaccine is inexpensive to produce, which is key in developing a medicine for some of the poorest countries in the world.
"Remember, you're talking about half the world's population, living in the poorest of the poor places of the world. You're talking about African countries, many southeast Asian countries, many countries in Latin America...and these are really poor people. So, if you want to make a vaccine for those people, it has to be really affordable and you need to be able to make it cheap...very cheap."
"We think that producing this protein in bacteria will make it very cost effective for large-scale vaccine production."
The next step will be to develop a version of the vaccine that can be used in clinical trials, Kumar said.
"As soon as we get the funding...we have to get permission from the Food and Drug Administration, and then go for clinical trials of this vaccine. So, we still have a long way to go. But, yes, it's very exciting and we are very excited with the results we have seen so far."
Transmission blocking vaccines, though not yet widely tested in humans, have the potential to be used in conjunction with more traditional malaria vaccines and other interventions, such as malaria drugs and bed nets, to fight the complex tropical disease and ultimately aid in the gradual elimination of the parasites.
Kumar's studies are funded by the National Institutes of Health.