A NOVEL METHOD OF PURIFYING LUNG SURFACTANT PROTEIN-A AND PROTEIN-D FROM THE LUNG LAVAGE OF ALVEOLAR PROTEINOSIS PATIENTS AND FROM POOLED AMNIOTIC-FLUID

A simple procedure has been developed for the purification of the surf actant proteins SP-A and SP-D from lung lavage of patients with alveol ar proteinosis. The SP-D is purified by fractionation of the supernata nt obtained after spinning the lavage at 10 000 x g for 40 min, while the bulk of the SP-A is purified by fractionation of the pellet. The s upernatant is applied to a maltosyl-agarose column and the bound SP-D is specifically eluted using MnCl2. The pellet is solubilised in 6 M u rea and, following renaturation, the solubilised proteins are applied to maltosyl-agarose and SP-A eluted using a gradient of EDTA. Both SP- A and SP-D are further purified by gel-filtration on Superose-6, This procedure has also been used to prepare successfully human SP-A and SP -D from amniotic fluid and may be generally applicable to the isolatio n of these surfactant proteins from lung washings obtained from other species. (C) 1998 Elsevier Science B.V. All rights reserved.