FIG. 3.
Immobilized hIgG, but not immobilized hIgG F(ab′)2 fragments or soluble hIgG, mediates viral suppression in MDM. (A) Plastic-bound hIgG corresponding to deposited amounts of hIgG was measured by using a bicinchoninic acid colorimetric assay. Soluble hIgG was added to cultured MDM, and cells were immediately infected with HIV-1BaL. A nonlinear correlation between deposited and bound hIgG concentrations in the measurable range was observed. (B) MDM (105 cells/well) were seeded in wells coated with whole hIgG or hIgG F(ab′)2 fragments (100 μg of deposited protein per well). Cells were infected with HIV-1BaL, and infection was monitored by measuring p24 antigen in the culture supernatants. The results presented here correspond to the means of results from four independent wells ± standard deviations and are representative of those from two experiments performed with MDM from each of two different donors. (C) MDM (105 cells/well) were exposed to increasing concentrations of soluble hIgG or to the corresponding bound hIgG (ranging from 0.3 to 100 μg of hIgG/well) and infected with HIV-1BaL. HIV-1 replication in hIgG-exposed MDM is expressed as the percentage of p24 production by control MDM on day 12 postinfection. Results are presented as the means of results from four independent replicates ± standard deviations. Results from one representative experiment of two performed with cells from different donors are shown.