Immunology Research Group
Welcome to Stellenbosch University

​Senior Scientists

Prof Novel Chegou

​​Head of Biomarker Lab

Tel: +27 21 938 9953


Novel N Chegou (PhD) is an Associate Professor and co-leads the diagnostic biomarker research efforts of SU-IRG. He was trained as a Medical Laboratory Scientist at the Faculty of Health Sciences, University of Buea, in Cameroon after which he joined the University and completed his postgraduate and postdoctoral training in the field of Tuberculosis Immunology, under Prof Gerhard Walzl.  

Prof Chegou's research work mainly focuses on the discovery of biomarkers for the diagnosis of tuberculosis and monitoring of the response to treatment. He is particularly interested in the development of simple, field-friendly point-of-care diagnostics for the management of TB in resource-constrained settings. The group conducts research in both adults and children, and in both pulmonary and extrapulmonary TB, with some animal (mouse)-based projects ongoing. 

Prof Chegou is a South African National Research Foundation (NRF) rated scientist and an EDCTP Senior Fellow. He holds an EDCTP-Senior Fellowship (grant no: TMA2018SF-2470) for the project entitled "Evaluation of new biomarker-based approaches for improving the diagnosis of childhood tuberculous meningitis (TBMBIOMARKERS)".


Dr André Loxton​​

​​Head of B-cell Lab (#LoxtonLab)​

Tel: +27 21 938 9953


Dr André G Loxton is a specialist scientist of the SA Medical Research Council (SAMRC) and member of SU-IRG. He completed his studies at Stellenbosch University and his PhD focused on regulatory T-cells during HIV-TB co-infection.

Dr Loxton currently leads the B-cell laboratory and his research continues around the different cell phenotypes, specifically regulatory (killer) B-cells (currently evaluating new roles for these cells) present during latent and active Tuberculosis and HIV disease and the discovery of associated biomarkers of infection, disease progression and treatment response. 

He is actively involved in TB vaccine studies and leads the vaccine end-point characterization. He is experienced in a wide range of research-related activities, from operational issues of cohort recruitment and follow-up to advanced immunological and molecular biology laboratory techniques, which is ideally suited for research in Tuberculosis in a high endemic area.

Dr Nelita du Plessis​​

Head of Innate Immunity Lab

Tel: +27 21 938 9953


Key areas of expertise: Innate immunity, Regulatory myeloid cells, Tuberculosis host-directed therapies, Site-of-disease responses, 3D granuloma models, Helminth infections

Dr Nelita du Plessis is an infectious disease immunologist at the Stellenbosch University Immunology Research Group, heading the Innate Immunity lab. She completed her undergraduate studies and obtained Hons B.Sc (Molecular Genetics) and M.Sc (Human Genetics) degrees from Stellenbosch University.  She completed her PhD in Biomedical Sciences in 2012.

She has a keen interest in innate immunity in the context of Tuberculosis (TB) and helminth infections, particularly the impact of regulatory myeloid cells (RMC), such as myeloid-derived suppressor cells (MDSC), on host immunity. Her research focuses on developing myeloid-targeted host-directed therapies for TB; host immune responses at the lung infection site of people with-/without- TB exposure or disease; and optimization of biomimetic technologies for 3D TB infection models. Her work integrates cellular, transcriptomic and epigenetic technologies to unravel mechanisms of immune susceptibility and protection in TB.​

Dr. du Plessis is an NRF rated scientist and an ECTP Career Development Fellow (CDF-1546) for investigating the functional effect of small-molecule targets on MDSC function and phenotype in TB. She is co-site PI on the National Institute of Allergy and Infectious Diseases (NIAID) funded contract “Immune Mechanism of Protection Against Mycobacterium Tuberculosis Center (IMPAc-TB) (Cascade study- K. Urdahl)" and the NIH funded studies “Lung Resident, MR1-Restricted T-Cells: Association with Differential Outcomes Following Exposure to M. tuberculosis - D. Lewinsohn" and “T cell recognition of the MR1 presented microbial metabolome - E. Adams".​

Selected publications:

Dr Léanie Kleynhans​​

Head of TB and Diabetes Lab

Tel: +27 21 938 9953


Dr Léanie Kleynhans is a senior scientist with the Stellenbosch University Immunology Research Group. She obtained both her undergraduate BSc and Hons BSc (Medical Biochemistry) degrees from the University of Stellenbosch before completing her PhD (upgraded from MSc) in Molecular Biology in 2012. Her PhD focussed on the effects of the three-month injectable contraceptive, Medroxyprogesterone acetate (also known as Depo Provera), on host immune responses to Mtb in humans and in a mouse model.

Her current research interest is the interplay between the immune and endocrine system as well as the immunomodulatory properties of endogenous hormones on the immune system in the context of TB. Léanie particularly focuses on the link between TB and type 2 diabetes and investigates whether the endocrine dysregulation during type 2 diabetes contributes to increased risk of TB. Dr Kleynhans is a co-investigator on an NIH RO1 grant under the US-South Africa collaborative framework entitled “Altered endocrine axis during type 2 diabetes and tuberculosis risk".


Prof Katharina Ronacher


Prof Katharina Ronacher joined SU-IRG in 2006 and spent over 11 years working on TB biomarkers under the guidance of Prof Gerhard Walzl. Her research focused on the link between TB and Type-2 diabetes (T2D) for which she was awarded a 5-year NIH RO1 grant in 2015 to investigate whether the endocrine dysregulation during T2D contributes to increased risk of TB. At the beginning of 2017, Prof Ronacher re-located to the Translational Research Institute, Mater Research Institute at the University of Queensland in Australia, where she now heads the Infection, Immunity and Metabolism Research Group. She continues to hold an extraordinary appointment at Stellenbosch University, a C2 rating from the NRF and active collaborations with Prof Walzl and Dr Leanie Kleynhans from SU-IRG.