An enzyme immunoassay for quantitation of a type 2 pneumocyte-specific surfactant-associated antigen in bronchoalveolar lavage fluid.

A sensitive, specific and reproducible assay for quantitation of a surfactant-associated antigen in mouse bronchoalveolar lavage fluid is described. The procedure employed was a non-equilibrium competitive enzyme immunoassay in which detection of unreacted antibody was significantly enhanced by the use of a second antibody and peroxidase-antiperoxidase as the reporter label. The sensitivity of the assay was such that bronchoalveolar lavage fluid had to be diluted 15 to 30-fold prior to assay. No interference by serum proteins or soluble tissue proteins was observed. This assay may provide in vitro quantitative assessment of the functional status of type 2 pneumocytes.