Journal of virology 2017 07 12() pii 10.1128/JVI.00700-17
Studying HIV-infected individuals who control HIV replication (elite controllers, ECs) enable exploration of effective anti-HIV immunity. HIV Env- and non-Env-specific antibody-dependent cellular cytotoxicity (ADCC) may contribute to protection from progressive HIV infection but the evidence is limited. We recruited 22 ECs and matched them with 44 viremic subjects. HIV Env- and Vpu-specific ADCC responses were studied in sera using a novel ELISA-based dimeric recombinant soluble (rs) FcγRIIIa-binding assay, surface plasmon resonance, antibody-dependent natural killer (NK) cell activation assays and ADCC-mediated killing assays. ECs had higher levels of HIV Env-specific antibodies capable of binding FcγRIIIa, activating NK cells and mediating Granzyme B activity (all p<0.01) compared to viremic subjects. ECs also had higher levels of antibodies against a C-terminal 13-mer Vpu peptide capable of mediating FcγRIIIa-binding and NK cell-activation compared to viremic subjects (both p<0.05). Our data associate Env-specific and Vpu epitope-specific ADCC in effective immune responses against HIV among ECs. Our findings have implications for understanding the role of ADCC in HIV control.IMPORTANCE Understanding immune responses associated with elite control of HIV may aid the development of immunotherapeutic and vaccine strategies for controlling HIV infection. Env is a major HIV protein target of functional antibody responses that are heightened in ECs. Interestingly, EC antibodies also target Vpu, an accessory protein crucial to HIV, which degrades CD4 and antagonizes tetherin. Antibodies specific to Vpu are a common feature of the immune response of ECs that may prove of functional importance to the design of improved ADCC-based immunotherapy and preventative HIV vaccines.