Objective: The objective of this study is to determine the breadth of HIV-1 Env-specific antibody-dependent cellular cytotoxicity (ADCC) in HIV controllers and HIV progressors with a view to design globally relevant HIV vaccines.
Design: The breadth of ADCC towards four major HIV-1 Env subtypes was measured in vitro for 11 HIV controllers and 11 HIV progressors.
Methods: Plasma from 11 HIV controllers (including long-term slow progressors, viremic controllers, elite controller and posttreatment controller) and 11 HIV progressors, mostly infected with HIV-1 subtype B, was analysed for ADCC responses. ADCC assays were performed against 10 HIV-1 gp120 and 8 gp140 proteins from four major HIV-1 subtypes (A, B, C and E) and 3 glycosylation-mutant gp140 proteins.
Results: ADCC-mediated natural killer cell activation was significantly broader (P = 0.02) and of higher magnitude (P < 0.001) in HIV controllers than in HIV progressors. HIV controllers also showed significantly higher magnitude of ADCC-mediated killing of Env-coated target cells than HIV progressors to both HIV-1 subtype B and the heterologous subtype E gp140 (P = 0.001). We found good ADCC reactivity to subtype B and E Envs, less cross-reactivity to subtype A and minimal cross-reactivity to subtype C Envs. Glycosylation-dependent ADCC epitopes comprise a significant proportion of the total Env-specific ADCC response, as evident from the reduction in ADCC to nonglycosylated form of HIV-1 gp140 (P = 0.004).
Conclusion: HIV controllers have robust ADCC responses that recognize a broad range of HIV-1 Env. Glycosylation of Env was found to be important for recognition of ADCC epitopes. Identifying conserved ADCC epitopes will assist in designing globally relevant ADCC-based HIV vaccines.
aDepartment of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Parkville
bMelbourne Sexual Health Clinic, Carlton
cInfectious Diseases Unit, Alfred Hospital, Prahran, Victoria, Australia.
Correspondence to Stephen J. Kent, Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Parkville, VIC 3010, Australia. Tel: +61 3 8344 9939; fax: +61 3 8344 3846; e-mail: email@example.com
Received 10 December, 2013
Revised 1 April, 2014
Accepted 12 April, 2014