Figure 8.

Binding of SP-A1 (6A²) and SP-A2 (1A⁰) variants to phagocytic and non-phagocytic cells and expression of cell surface proteins in AMs of SP-A1 (6A²) and SP-A2 (1A⁰) mice. (A) depicts binding of rat AM and two cell lines (THP-1, a macrophage-like and phagocytic and the other CHO, non-phagocytic) to SP-A variants expressed by stably transfected mammalian cell lines. Cells (AM, THP-1, and CHO) were adhered to 96-well tissue culture plates and incubated with purified SP-A2 (1A⁰) and SP-A1 (6A²). Cells were then washed and lysed and the SP-A content of the lysates determined by Western dot blot and densitometry. A significant increase in binding of SP-A2 vs. SP-A1 (p = 0.0007) to AM was seen as was for the phagocytic THP-1 cells (p = 0.0015), but no differences were observed with the non-phagocytic CHO cells. (B) Depicts expression of SP-A binding proteins from AMs of hTG SP-A1 (6A²) and SP-A2 (1A⁰) mice. Bronchoalveolar lavage was performed on hTG SP-A2 (1A⁰) and SP-A1 (6A²) mice. AM were stained for SP-A binding proteins CD14 and TLR2 and analyzed by flow cytometry. A significant increase in expression of CD14 (p = 0.036) and TLR2 (p = 0.022) was seen in SP-A2 (1A⁰) AM vs. SP-A1 (6A²) AM. ^*p < 0.05, ^***p < 0.001.