Abstract
Apo-protein(s) have been demonstrated in surfactant material from mammalian species. We have used immunologic probes to detect and characterize proteins from alveolar wash from adult rat and from amniotic fluid (human) and lung lavage from adult humans. Antibodies were generated with both surfactants which recognize Mr 35-37,000 (Apo A) and Mr 28,000 (after sulphydryl reduction). Anti sera were species specific. Apoproteins were analyzed by (SDS-PAGE) and 2-D, isoelectric focusing (IEF-PAGE) followed by transblot to nitrocellulose and immunoperoxidase labelled with the species specific antibodies. Rat Apo A is acidic pI 4.4-4.8 with 6 immunoreactive species at 37,000 and 3 at 35,000. Antisera stained Type II cells, primarily labelling lamellar bodies. An ELISA assay was used to quantitate apoprotein in rat lung (18d gestation to adulthood). Apoproteins were first detected by 20d gestation, dramatically increasing at 21d gestation. Apoprotein (A) obtained from human samples also migrated with Mr 35-37,000, isoelectric point similar to the rat, pI 4.4-4.8. The more acidic species were more prominent in rat than in the human apoprotein at Mr 37,000. Charge heterogeneity of apo A's suggests that there is significant post-translational alteration of these molecules, likely related to glycosylation or other co-valent modification. Rat apoproteins are first expressed in late gestation in the rat. While structurally similar (pI and mol wt) there are major immunologic differences between human and rat surfactant apoproteins.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Whitaett, J., Hull, W., Petro, M. et al. RAT AND HUMAN SURFACTANT ASSOCIATED APOPROTEINS. Pediatr Res 18 (Suppl 4), 409 (1984). https://doi.org/10.1203/00006450-198404001-01898
Issue Date:
DOI: https://doi.org/10.1203/00006450-198404001-01898