The radioimmunoassay of pulmonary surface active material in sheep lung.

We have developed a radioimmunoassay for pulmonary surface active material in sheep lung using solid-phase techniques. The method is capable of measuring 1 to 10 picomoles of antigen with a reproducibility of about 15 per cent and can be carried out in the presence of a 100-fold excess of either serum or lipid. It appears to be specific for the antigen found in pulmonary surfactant.