1. Department of Molecular and Cell Biology, Faculty of Science, University of Cape Town, Cape Town, South Africa.
2. Centre for the AIDS Programme of Research in South Africa, University of KwaZulu-Natal, Durban, South Africa.
3. Institute of Infectious Diseases and Molecular Medicine, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
4. Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.