Detection of the type II cell or its precursor before week 20 of human gestation, using antibodies against surfactant-associated proteins

Abstract

The present study was performed to find out whether the type II alveolar epithelial cell or its precursor (an approximately cuboidal cell lacking multilamellar bodies) is present before the twentieth week of human gestation. For this purpose we used an antibody, SALS-Hu(E), which recognizes the human type II cell on the basis of surfactant-associated proteins. Application of SALS-HuE (by indirect immunofluorescence) to acetone-fixed frozen sections of fetal lung tissue gave a distinct staining of the cuboidal or low columnar epithelial cells lining the end-pieces of the tubular system of fetal lung (initially only a few): this staining started around weeks 10 to 12 after conception. Around week 16 some of the labeled epithelial cells appeared to be rather flat and by week 19 a combined cellular and linear fluorescence pattern was seen. Columnar epithelial cells of the prospective bronchial portion did not show this specific staining. Our results indicate that the type II cell or its precursor cell is indeed present in the pseudoglandular period of human lung development, i.e., starting around the tenth to twelfth week. This cell type lines the acinar tubule, the basic structure of the pulmonary acinus. Transformation of this cell type into the type I alveolar epithelial cell seems to start in week 16.

The proximal border of the human respiratory unit, as shown by scanning and transmission electron microscopy and light microscopical cytochemistry

“…These studies provide some information on cell properties, but not on cellular distribution patterns along the bronchioles, and generally consider both the columnar and the cuboid cell types present in the lining as bronchial epithelial cells. This classic view on the epithelial composition is not supported, however, by our developmental studies in humans (Otto-Verberne et al, 1988) and a nonhuman primate, the rhesus monkey (Ten Have-Opbroek and Plopper, 1989).…”

“…The specificity of these antibodies, called specific antilavage serum, human (SALS-Hu), was assessed by Western blot analysis and immunohistochemistry (Otto-Verberne et al, 1988). These studies also showed the type I1 cell specificity of SALS-Hu in both developing and adult human lungs (Otto-Verberne et al, 1988). Blood samples taken before immunization were used as control (preimmunization serum, PSI.…”

“…SP-A antibodies (rabbit anti human) were prepared in our laboratory with a surfactant enriched fraction of bronchoalveolar lavage fluid from adult human lung (Otto-Verberne et al, 1988). The specificity of these antibodies, called specific antilavage serum, human (SALS-Hu), was assessed by Western blot analysis and immunohistochemistry (Otto-Verberne et al, 1988).…”

The lungs in congenital diaphragmatic hernia: Do we understand?

“…26 They have been detected in the mouse from day 14 26 on, in the rat from day 16, 57 and in human lungs from week 11-12. 58 Further differentiation of the type II cells into type I cells starts in the human from gestational week 16 onward. 58 Alveolar type II cells are the only cells in the lung responsible for the production, storage, and secretion of pulmonary surfactant. Surfactant is composed of 85 59,60 The composition of surfactant phospholipids and proteins, as well as their functions, have been reviewed repeatedly.…”

Functional overexpression of wild‐type p53 correlates with alveolar cell differentiation in the developing human lung

“…Around 16 weeks a.c., there is also a third stage in the alveolar epithelial cell differentiation, mainly in those areas of the acinus that are close to capillaries. This is a 'flatter' cell type, ranging in shape from cuboidal to squamous, that represents an intermediate stage in the differentiation of prospective cuboidal type II cells into prospective squamous type I cells (Ten Have-Opbroek, 1979Otto-Verberne and Ten Have-Opbroek, 1987;Otto-Verberne et al, 1988;Ten Have-Opbroek and Plopper, 1992;Brandsma et al, 1993Brandsma et al, , 1994. As a consequence of this cell 'flattening,' the acinar tubules start to transform into derivative structures, namely prospective alveolar ducts and sacs (canalicular period of lung development).…”