Dr Leopold D. Tientcheu
Dr Leopold D. Tientcheu, MRC Unit, The Gambia
Investigating heterogeneous African host population responses to Mycobacterium tuberculosis complex lineages causing tuberculosis: implications for host directed therapy
I am interested in the interactions between the bacteria (Mycobacterium tuberculosis) that cause tuberculosis (TB), the human immune response to mycobacteria, and TB therapy.
My interest in TB research began in 2007 with my Master of Science thesis project. Using molecular methods, I set out to identify genetic mutations that confer drug resistance to Mycobacterium tuberculosis. I found that mutations differ between two geographical regions of Cameroon. I also showed that radio-isotope assays to evaluate the spread of drug resistant M. tuberculosis were as reliable and efficient as the standard, time-consuming drug susceptibility testing cultures.
My subsequent doctoral studies at the London School of Hygiene & Tropical Medicine were focused on studying the differences between the immune responses of M. africanum and M. tuberculosisinfected patients in The Gambia following treatment. My results suggest that M. tuberculosis can suppress the immune response of someone whose immune-system is competent; the response is then restored following chemotherapy. I also found that M. africanuminfected patients recovered less well than those with M. tuberculosis after treatment. One explanation is that M. africanum patients respond relatively poorly to the treatment regimen. Another is that M. africanum patients have a preexisting defective immune profile; this could explain why they succumb to less virulent mycobacteria. These results have important public health implications particularly in Africa, where M. africanum is more common.
As a postdoctoral researcher at the MRC Gambia Unit, I have continued to investigate how different M. tuberculosis complex lineages influence TB pathogenesis, host immune responses and outcomes of chemotherapy in both adult and children. I lead the laboratory aspect of a Childhood TB Program aiming to improve the diagnosis and treatment monitoring in children.
I chose a short AREF Fellowship, of three months. The award will enable me to build on the Unit’s TB Program and to strengthen collaboration with my hosts at the University of Cape Town (UCT), a well-established centre that brings together many groups working on different aspects of TB. I shall work with Professor Robert J Wilkinson and Dr Anna Coussens, scientists with outstanding track records of competitive large grant awards.
During the Fellowship I shall be working towards an experimental protocol and a competitive research proposal to submit to a major funding body. If I achieve that, the AREF Fellowship will have been a significant stepping-stone in my scientific career.