Leishmania, vaccine development, Better Medicines Group

Leishmaniasis is a disease caused by infection with the protozoan parasite Leishmania, which is transmitted by female sand flies. The type of disease caused by the parasite depends on the infecting species and the host's immune response but three main forms occur, cutaneous, mucocutaneous and visceral leishmaniasis (1). The World Health Organisation estimates that 350 million people, living in 98 countries, are at risk of contracting leishmaniasis, and each year approximately 1.5 million new cases of cutaneous and 500,000 of visceral leishmaniasis are reported. In terms of disease burden, leishmaniasis is responsible for 2,357,000 DALYs (Disability-Adjusted Life Years) lost due to ill effects caused by the disease.

We have shown that is it possible to protect against Leishmania infection by using gamma glutamyl cysteine synthetase as a vaccine candidate (2-4).  We have now changed the expression vector for recombinant protein from Escherichia coli to Leishmania tarentolae. In this project the student will identify the optimal conditions for production of recombinant protein from the expression vector and scale up protein production.  The student will identify methods to quality control the recombinant protein production and determine endotoxin levels. The effect of vaccination with this protein by different routes will be determined and the overall aim is to produce a formulation that can be given by the oral route. 

Recombinant DNA technology, aseptic tissue culture techniques, maintaining parasite organisms, assessment of immune responses using ELISA assays, lymphocyte proliferations assays, Greiss assays, PCR. We will also use bioluminescent imaging to determine parasite burden in infected animals as well as traditional methods e.g. direct counting of parasites in tissues.

1 Mears ER, Modabber F, Don R, Johnson GE. (2015) A Review: The Current In Vivo Models for the Discovery and Utility of New Anti-leishmanial Drugs Targeting Cutaneous Leishmaniasis. PLoS Negl Trop Dis. 9:e0003889.

2. Carter KC, Henriquez FL, Campbell SA, Roberts CW, Nok A, Mullen AB, McFarlane E.(2007)  DNA vaccination against the parasite enzyme gamma-glutamylcysteine synthetase confers protection against Leishmania donovani infection.Vaccine.25:4502-9.

3. Henriquez, FL, Campbell, SA, Roberts, CW, Mullen, AB, Burchmore, R & Carter, KC (2010) Vaccination with recombinant Leishmania donovani gamma-glutamylcysteine synthetase fusion protein protects against L. donovani infection. Journal of Parasitology, 96: 929-936.

4. Campbell, SA, Alawa, J, Doro, B, Henriquez-Mui, F, Roberts, CW, Nok, A, Alawa, CBI, Alsaadi, M, Mullen, AB & Carter, KC (2012) Comparative assessment of a DNA and protein Leishmania donovani gamma glutamyl cysteine synthetase vaccine to cross-protect against murine cutaneous leishmaniasis caused by L. major or L. mexicana infection. Vaccine 30: 1357-1363.