title: Growth hormone augments superoxide anion secretion of human neutrophils by binding to the prolactin receptor.
abstract: Recombinant human growth hormone (HuGH) and human prolactin (HuPRL), but not GH of bovine or porcine origin, prime human neutrophils for enhanced superoxide anion (O2-) secretion. Since HuGH, but not GH of other species, effectively binds to the HuPRL receptor (HuPRL-R), we used a group of HuGH variants created by site-directed mutagenesis to identify the receptor on human neutrophils responsible for HuGH priming. A monoclonal antibody (MAb) directed against the HuPRL-R completely abrogated O2- secretion by neutrophils incubated with either HuGH or HuPRL, whereas a MAb to the HuGH-R had no effect. The HuGH variant K172A/F176A, which has reduced affinity for both the HuGH-binding protein (BP) and the HuPRL-BP, was unable to prime human neutrophils. This indicates that priming is initiated by a ligand-receptor interaction, the affinity of which is near that defined for receptors for PRL and GH. Another HuGH variant, K168A/E174A, which has relatively low affinity for the HuPRL-BP but slightly increased affinity for the HuGH-BP, had much reduced ability to prime neutrophils. In contrast, HuGH variant E56D/R64M, which has a similar affinity as wild-type HuGH for the HuPRL-BP but a lower affinity for the HuGH-BP, primed neutrophils as effectively as the wild-type HuGH. Finally, binding of HuGH to the HuPRL-BP but not to the HuGH-BP has been shown to be zinc dependent, and priming of neutrophils by HuGH was also responsive to zinc. Collectively, these data directly couple the binding of HuGH to the HuPRL-R with one aspect of functional activation of human target cells.
authors.affiliation: Department of Animal Sciences, University of Illinois, Urbana 61801.
authors.forename: Y K
authors.initials: YK
authors.lastname: Fu
authors.forename: S
authors.initials: S
authors.lastname: Arkins
authors.forename: G
authors.initials: G
authors.lastname: Fuh
authors.forename: B C
authors.initials: BC
authors.lastname: Cunningham
authors.forename: J A
authors.initials: JA
authors.lastname: Wells
authors.forename: S
authors.initials: S
authors.lastname: Fong
authors.forename: M J
authors.initials: MJ
authors.lastname: Cronin
authors.forename: R
authors.initials: R
authors.lastname: Dantzer
authors.forename: K W
authors.initials: KW
authors.lastname: Kelley
mesh_terms: D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002417:Cattle; D002455:Cell Division; D002478:Cells, Cultured; D013006:Growth Hormone / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D008223:Lymphoma / Q000473:pathology; D009504:Neutrophils / Q000378:metabolism*; D011981:Receptors, Prolactin / Q000502:physiology*; D013481:Superoxides / Q000378:metabolism*; D013552:Swine; D015032:Zinc / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D011981:Receptors, Prolactin; D013481:Superoxides; D013006:Growth Hormone; D015032:Zinc