Figure 6.

The presence of Nef and Vpu efficiently shields HIV-infected T cells from ADCC mediated by plasma from HIV-infected individuals. CEM.NKR cells were infected with viruses as mentioned in Figure 1 legend. (A) Target cells were stained with plasma samples from an HIV seronegative person (164HH) or from HIV-infected individuals (different plasmas were color coded). Env expression was determined as described in Figure 1 legend. (B-C) Target cells incubated with plasmas as described in (A) were analyzed for their susceptibility to ADCC using PBMC as effector cells. Net Ab-specific cell lysis was computed as described in Figure 2 and obtained following subtraction of background killing of the same targets induced by the 164 HH plasma. Panel B depicts ADCC activity mediated by patient plasmas, which appeared enriched with A32-like anti-Env Abs. Panel C illustrates ADCC activity induced by patient plasmas containing A32-like as well as other ADCC-competent anti-Env Abs. These characteristics of the patient plasmas were established post-analysis. The four sets of numbers indicated on the right hand side of the lines represent four donors. Data shown are representative of 3 analyses using plasmas from 6 infected individuals and PBMCs from 8 donors. Statistical analysis of data was done using paired Student’s t-tests.