title: The effects of eosinophil-granule major basic protein on lung-macrophage superoxide anion generation.
abstract: The effects of major basic protein (MBP) on superoxide anion release in vitro from normal guinea pig (GP) alveolar macrophages (AM) was determined. Native MBP at 55 micrograms/ml had an immediate effect (reduction) on phorbol myristate acetate (PMA)-induced (p less than 0.01) and spontaneous (p = 0.055) superoxide (O2-) release by GP AMs. A similar effect was not observed from AMs incubated for 24 hours with MBP before assessment of O2- release. However, after AMs were incubated with MBP for 48 hours, again there was a significant reduction observed in both PMA-induced (p = 0.01) and spontaneous (p = 0.002) O2- release compared to that of control cultures. The immediate effect of MBP on AM O2- release was not due to cytotoxicity of MBP for AM. In contrast, the effect observed after 48 hours of culture was due, in part, to a direct toxic effect of the MBP on the AM because the viability of AM cultured for 48 hours with MBP (55 micrograms/ml) was 63.6% +/- 13% compared to the viability of control cultures of AM that was 83.9% +/- 7%; p = 0.03. The effect of MBP on AM O2- release at 48 hours was progressive over concentrations ranging from 2 to 55 micrograms/ml. These data suggest that native MBP can affect adversely PMA-induced and spontaneous release of O2- by GP AMs and that this effect depends only in part on the cytotoxic properties of MBP.
authors.affiliation: Research Service, West Haven Veterans Hospital, CT 06516.
authors.forename: J A
authors.initials: JA
authors.lastname: Rankin
authors.forename: P
authors.initials: P
authors.lastname: Harris
authors.forename: S J
authors.initials: SJ
authors.lastname: Ackerman
mesh_terms: D000293:Adolescent; D000818:Animals; D000838:Anions; D001798:Blood Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D047091:Eosinophil Granule Proteins; D004804:Eosinophils / Q000378:metabolism*; D006168:Guinea Pigs; D006801:Humans; D016676:Macrophages, Alveolar / Q000187:drug effects* / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D012260:Ribonucleases; D013481:Superoxides / Q000378:metabolism*; D013997:Time Factors
chemical_list: D000838:Anions; D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D013481:Superoxides; D012260:Ribonucleases; D010100:Oxygen