TB Researchers Obtain PhDs

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Dr Navisha Dookie, Dr Santosh Kumar and Dr Parveen Sobia all graduated with PhDs in Medical Microbiology following studies aimed at advancing global TB research.

The three were supervised by UKZN Infection Control Chief Specialist, Professor Prashini Moodley.

Dookie’s study contributed to understanding the dynamics of antimicrobial resistance and the complexity of the mechanisms mediating resistance in M.tuberculosis (M.tb) strains circulating in our setting.

The Centre for the AIDS Programme of Research in South Africa post-doctoral Research Fellow said understanding the underlying resistance mechanisms driving drug resistance in M.tuberculosis was pivotal in the design of rapid molecular based assays and had the potential to impact on the development of novel drugs and regimens for the disease. ‘My current research aims to identify innate immune correlates of the human host that are protective against recurrent tuberculosis infection. The identification of such biomarkers was crucial for the development of innovative strategies for tuberculosis management and vaccine design.

‘Mycobacterium tuberculosis infects 9 million individuals and kills almost 2 million people every year. The only vaccine available, Bacillus Calmette-Guerin (BCG), has been used since its development in 1921,’ said Kumar. His study was titled: “Improving the Efficacy of BCG Vaccine by Concomitant Inhibition of T Regulatory and T Helper 2 cells”.

Kumar said although BCG induced host protective T helper 1 (Thl) cell immune responses which play a central role in host protection, it also induced Th2 and Treg responses - subsets that facilitate pathogenesis during M.tb infection. ‘The resultant protective immunity is therefore neutralised. Additional methods to enhance protective immune responses are needed,’ he said.

Researchers are a step closer to designing new TB drugs and vaccines thanks to a study by Sobia which exposed the essential virulence role of TlyA in the pathogenesis of M.tb which may be a major advancement in providing a better understanding of host pathogen interaction and designing new therapeutics and vaccines.

Sobia said M.tb was a causative agent of the TB disease – ‘a major cause of death worldwide’. He said although various virulence factors of M.tb had been identified, its pathogenesis remained incompletely understood. Mice infected with TlyA deficient mutant M.tb organisms in the study exhibited increased host protective immune responses, reduced bacillary load, and increased survival compared with animals infected with wild type M.tb. Therefore it was likely that M.tb employs TlyA as a host evasion factor, thereby contributing to its virulence, said Sobia.

Sobia arrived at UKZN in 2014 as an international PhD student. ‘Before coming here I was working as Senior Research Fellow in New Delhi.’

She plans to join the UKZN post-doctoral fellowship programme under the mentorship of Professor AW Sturm in a project looking at the development and optimisation of a rapid diagnostic methodology for detection of M.tb.

Moodley congratulated all three candidates for producing outstanding work that contributed to the further understanding of the pathogenesis of M.Tb.

Lunga Memela