The neck domain of DCIR is important for interaction with HIV-1. (A) Raji-CD4 cells were nucleofected with either an empty control vector (left panel) or a mammalian expression vector coding for a neck-deleted DCIR mutant (ie, DCIRΔneck) (right panel). Five hours later, flow cytometric analysis of DCIR was performed using a combination of PE-labeled anti-DCIR monoclonal Ab (dotted lines) and a control Ab (continuous lines). Data shown correspond to a single experiment representative of 5 combined independent experiments. (B) Parental (DCIR-negative) and DCIRΔneck-expressing Raji-CD4 (3 × 106 cells) were exposed to NL4-3 (300 ng p24) for 60 minutes at 37°C. After 3 washes with PBS to remove unabsorbed virus, cell-associated virus was quantified by measuring the p24 content. Data shown correspond to the means plus or minus SD of triplicate samples from 5 combined independent experiments. (C) Parental (DCIR-negative) and DCIRΔneck-expressing Raji-CD4 (1.5 × 105 cells) were exposed to NL4-3 (1.5 ng p24) for 2 hours at 37°C. After 3 washes with PBS to remove excess virus, cells were maintained in culture. Cell-free culture supernatants were collected at the indicated time points and assayed for the p24 content. Data shown correspond to the means plus or minus SD of triplicate samples and are representative of 5 combined independent experiments. The asterisk denotes statistically significant data (*P < .05).
