1. Department of Chemical Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
2. Department of Chemical Pathology, National Health Laboratory Service, Johannesburg, South Africa.
3. Department of Hematology and Molecular Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
4. Department of Immunology, University of Pretoria, Johannesburg, South Africa.
5. Perinatal HIV Research Unit, Chris Hani Baragwanath Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
6. Center for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa.
7. SA MRC Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.