title: Mouse natural killer (NK) cells express the nerve growth factor receptor TrkA, which is dynamically regulated.
abstract: BACKGROUND
  Nerve growth factor (NGF) is a neurotrophin crucial for the development and survival of neurons. It also acts on cells of the immune system which express the NGF receptors TrkA and p75(NTR) and can be produced by them. However, mouse NK cells have not yet been studied in this context.
  
  
  RESULTS
  We used cell culture, flow cytometry, confocal microscopy and ELISA assays to investigate the expression of NGF receptors by NK cells and their secretion of NGF. We show that resting NK cells express TrkA and that the expression is different on NK cell subpopulations defined by the relative presence of CD27 and CD11b. Expression of TrkA is dramatically increased in IL-2-activated NK cells. The p75(NTR) is expressed only on a very low percentage of NK cells. Functionally, NGF moderately inhibits NK cell degranulation, but does not influence proliferation or cytokine production. NK cells do not produce NGF.
  
  
  CONCLUSIONS
  We demonstrate for the first time that mouse NK cells express the NGF receptor TrkA and that this expression is dynamically regulated.
authors.affiliation: Laboratory of Immunogenetics and Allergology, Centre de Recherche Public de la Santé, Luxembourg, Luxembourg.
authors.forename: Natacha
authors.initials: N
authors.lastname: Ralainirina
authors.forename: Nicolaas H C
authors.initials: NH
authors.lastname: Brons
authors.forename: Wim
authors.initials: W
authors.lastname: Ammerlaan
authors.forename: Céline
authors.initials: C
authors.lastname: Hoffmann
authors.forename: François
authors.initials: F
authors.lastname: Hentges
authors.forename: Jacques
authors.initials: J
authors.lastname: Zimmer
mesh_terms: D000818:Animals; D039481:CD11b Antigen / Q000096:biosynthesis; D049109:Cell Proliferation; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005434:Flow Cytometry / Q000379:methods; D005786:Gene Expression Regulation; D007376:Interleukin-2 / Q000378:metabolism; D007694:Killer Cells, Natural / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal / Q000379:methods; D020932:Nerve Growth Factor / Q000378:metabolism; D020917:Receptor, trkA / Q000235:genetics*; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7 / Q000096:biosynthesis
chemical_list: D039481:CD11b Antigen; D007376:Interleukin-2; D017475:Receptors, Nerve Growth Factor; C517634:Ngfr protein, mouse; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D020932:Nerve Growth Factor; D020917:Receptor, trkA