Surfactant proteins A (SP-A) and D (SP-D): Levels in human amniotic fluid and localization in the fetal membranes

Surfactant protein secreted by the maturing mouse fetal lung acts as a hormone that signals the initiation of parturition

“…Like SP-A, the related collectin SP-D is developmentally regulated in fetal lung late in gestation, reaching maximal levels at term (35,36). SP-D protein also is evident in human amniotic fluid although its levels increase only modestly after 32 weeks of gestation (37), in contrast to the pronounced rise in SP-A (20,37). Although SP-D levels remained unchanged in lung tissues of adult transgenic mice that overexpressed recombinant SP-A (34) and in adult SP-A null mice (33), no information was provided regarding SP-D levels in the fetal lungs.…”

Immunological properties of human decidual macrophages – a possible role in intrauterine immunity

“…Macrophages isolated from the amniotic fluid of pregnant mice respond to fetal surfactant protein A (SP-A) by increasing IL-1b and NF-kB production, and this may trigger uterine activation and labour (Condon et al 2004). SP-A levels increase sharply in human amniotic fluid towards term (Miyamura et al 1994) and it would be of interest to study its effect on human DMs.…”

Surfactant proteins A and D protect mice against pulmonary hypersensitivity induced by Aspergillus fumigatus antigens and allergens

“…The selected dose of SP-A and SP-D was based on the physiological concentrations of these proteins reported in rodent lung lavage: the SP-A concentration in the rat lavage was 7.3 ± 0.8 µg/ml and the SP-D concentration in the lavage from C57Bl/6 mice 6-8 weeks of age was observed to be 552 ng/ml (16,17). For human lung lavage, the SP-A concentration ranges from 1 to 10 µg/ml and the SP-D concentration varies between 300 ng and 600 ng/ml (7,18).…”