Pulmonary surfactant is believed to contribute to decrease the alveolar surface tension to maintain the alveolar spaces. Monoclonal antibodies against human pulmonary surfactant apoproteins of 34-37 kDa were prepared. Indirect immunocytochemistry using this antibody was performed on the paraffin sections of pulmonary tissue obtained from newborns, stillborns and infants at autopsy. Results showed the staining profiles of newborn and stillborn specimens to be slightly different from those of infants, and also to be altered according to the degree of alveolar expansion or degeneration and/or putrefaction. The author confirmed the existence of apoproteins even in the putrefied pulmonary tissue of a case examined at 3 or 4 months after death. This staining method clarified that a newborn had died of Respiratory Distress Syndrome, ruling out the first suspected cause of infanticide. This paper discussed the usefulness of the antibody and its application to legal medicine
