Abstract: Objective To investigate the expression patterns of surfactant protein B (SP-B) and its role in the development of human fatal lung epithelial cells. Methods Human fetal lung tissues were obtained from 37 fetuses of 10-34 weeks at abortion with parental consent and from two newborn infants who died of non-pulmonary causes. SP-B expression in the lung tissues was examined by immunohistochemistry. Results SP-B was detected in the cytoplasm of nonciliated columnar epithelial cells of the human fetal lung in as early as the 16th week of gestation. The positive reaction of SP-B was enhanced during canalicular stages and was more intense in the distal than in the proximal airway epithelium. From the 25th week to the prenatal stage, SP-B expression underwent no significant changes in the primitive alveolar stage, but increased remarkably after birth. Conclusion The expression and secretion of SP-B reflects the maturation of the epithelial cells in human fatal lungs, and may closely associate with the survival ability of the newborn infants. 更多