Figure 1.

SR-A–deficient and –sufficient AMs bind TiO₂ equally. (A) Representative photomicrograph showing approximately similar binding of particles by SR-A–deficient (SR^−/−) and wild-type (SR^+/+) AMs incubated with unopsonized TiO₂ (original magnification 400). (B) SR^−/− and SR^+/+ AMs were pretreated with the SR blocker PI or the control polyanion CS or left untreated, and their binding of TiO₂ was determined by flow cytometry. (C) SR^−/− and SR^+/+ AMs show similar binding of TiO₂ in vivo as determined by intratracheal instillation of TiO₂ followed by BAL and flow cytometric analysis. TiO₂ binding is expressed as increase in flow cytometric RAS. The data represent the mean (± SEM) of three separate experiments (B) and three mice per treated group compared with one control (C). *Significantly different from TiO₂ alone, P < 0.006.