Figure 1.

Binding of HIV to human airway basal cells. A. Binding of HIV-1NL4-3. BC were exposed to the virus, washed and then lysed in 0.1% Triton-X. Virus binding was measured by HIV-1 p24 levels after 3 and 24 hr. B. Sensitivity of HIV binding to the BC to trypsin. After 3 hr of incubation, cells were incubated with 0.05% trypsin/EDTA for 5 min, washed, lysed and analyzed by HIV-1 p24 levels. C. Flow cytometry assessment of cell surface expression of heparan sulfate proteoglycans (HSPGs) in untreated and trypsin-treated basal cells. The solid line represents staining with monoclonal antibody against the indicated HSPG. The broken line represents staining with corresponding isotype control. Shown are the histograms of heparan sulfate and syndecans 1–4, each from one representative experiment of 3 independent experiments. D. Heparan sulfate inhibition of HIV binding to BC. Pretreatment of HIV with heparan sulfate at different concentrations inhibits HIV binding to airway BC in a dose-dependent manner. Results shown are the average of three independent experiments using cells from 3 different individuals. E. Effect of heparinase III pretreatment of BC on HIV binding. Prior heparinase III treatment on BC significantly abolishes HIV binding. F. HIV binds to, but does not replicate in airway BC. Shown is a time-course of BC levels of p24 following addition of HIV-1 to airway BC. Cell lysates were collected at the indicated time points and used for quantification of HIV-1 p24 levels. *p<0.05, **p<0.01, NL4-3 vs NL4-3 + heparan sulfate.