Altered morphology, growth, and biosynthetic activity of a type 2 pneumocyte-related cell strain induced by lymphokine-enriched supernatants of mitogen-stimulated spleen cells.
Hypertrophy and hyperplasia of type 2 pneumocytes during the evolution of subacute and chronic pulmonary injury cannot always be satisfactorily explained in terms of reparative responses to type 1 pneumocyte injury. We hypothesized that immunocompetent cells, evoked as part of the interstitial inflammatory response, may be secreting factors which affect proliferation and surfactant biosynthesis by type 2 pneumocytes. To evaluate this hypothesis in vitro, we tested the effects of lymphokine-enriched supernatants, from serum-free cultures of concanavalin A-stimulated spleen cells, upon the type 2 pneumocyte-related cell strain NAL 1A. Addition of these supernatants in culture induced irreversible morphologic and ultrastructural alterations in the NAL 1A cells, inhibited cell replication, and evoked increased and apparently abnormal surfactant phospholipid biosynthesis. Supernatants from unstimulated spleen cells had no effect. There was no evidence of toxic injury to the cells in culture, and an immunologically specific cytoplasmic protein continued to be expressed. The active factor(s) appeared to be a protein or peptide of greater than 10,000 molecular weight. A specific soluble factor such as is present in the mitogen-stimulated lymphoid cell supernatants may be capable of mediating a similar interaction with type 2 pneumocytes in vivo.
D000818:Animals; D002455:Cell Division; D002460:Cell Line; D003208:Concanavalin A / Q000494:pharmacology; D005260:Female; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000494:pharmacology*; D051379:Mice; D010743:Phospholipids / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000166:cytology* / Q000293:injuries / Q000378:metabolism; D013154:Spleen / Q000276:immunology
D008222:Lymphokines; D010743:Phospholipids; D011506:Proteins; D003208:Concanavalin A