Fig. 8

Size distribution of SP-A extracted from the lipid phase of bronchoalveolar lavage (BAL) fluid taken from an alveolar proteinosis patient. SP-A was extracted from the lipid phase of BAL with 6 M urea, 10 mM CHAPS, or 1% Triton X-100 in 10 mM Tris-HCl, pH 7.4, 5 mM EDTA, 150 mM NaCl. Solubilized proteins and an aliquot of filtered whole BAL were passed through a Superose 6 gel filtration column (Pharmacia). The running buffer was PBS, 5 mM EDTA (pH 7.3). Fractions (1 ml) were analyzed by ELISA to detect SP-A (OD 405). The relative amounts of each oligomer of SP-A were determined. The ratios for the three extraction methods for SP-A being similar, the average results for the extracted materials were calculated.