Immunologic differentiation of proteins in the surfactant system of the lung.

Immunoelectrophoresis revealed the following four protein components in the lung surfactant system of guinea-pigs: albumin, transferrin, IgG, and an organ-specific protein migrating in the beta-globulin range. These proteins probably take part in the formation of the hypophase of the alveolar lining layer and thereby influence the surface properties of the alveolar air-liquid interface.