1. Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
2. Centers for AIDS Research and Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
3. Africa Health Research Institute, K-RITH Tower Building, Durban 4001, South Africa
4. School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban 4001, South Africa