MRC PhD student

Level of study: PhD

Title: Immune responses to tuberculous and non-tuberculous mycobacteria in adult household contacts and HIV-exposed and unexposed infants in the Western Cape Province, South Africa.

Study Institution: University of Stellenbosch, Faculty of Health Sciences

Cohort
The level of immune recognition of non tuberculous mycobacteria (NTMs) by 14 weeks of age will have an effect on cellular immune responses to M. tuberculosis and BCG antigens at 14, 24 and 52  weeks of age. This effect will be different in infants vaccinated at birth compared to infants vaccinated at14 weeks, and will also be different in babies exposed to HIV (in utero or peripartum), compared to unexposed infants.

Hypothesis – Adult Cohort
Cellular immune responses to M. tuberculosis and NTMs will be detected in the study population and responses to closely related NTMs will be correlated. The magnitude of immune responsiveness to NTMs will have an effect on the magnitude of immune responsiveness to M. tuberculosis. Immune responsiveness to NTMs will lead to expression of different cytokine profiles.

Project summary
In addition to M. tuberculosis, other species of mycobacteria exist. They are known as non-tuberculous mycobacteria (NTMs). It has been shown that the level of immune responsiveness to NTMs has an effect on immunity to M. tuberculosis. NTMs are phylogenetically related to M. tuberculosis and therefore share many antigenic components. Identification of unique antigens in the closely related organisms will allow accurate discrimination between M. tuberculosis and NTM therefore minimizing false positive M.tb diagnosis and allowing real time NTM infection identification.

Supervisors: Dr Gillian Black and Prof G Walzl
MRC Unit: Centre for Molecular and Cellular Biology