title: Spontaneously active suppressive cells in canine peripheral blood.
abstract: The phenomenon of the unusually high spontaneous suppressive activity of cells in peripheral blood of dogs was analysed. The m/c (mitomycin C)-treated population of peripheral blood leucocytes (PBL) contained cells able to reduce the responsiveness of autologous cells by 48 +/- 15% (P less than 0.01) and their activity was not indomethacin dependent. Thoracic duct lymphocytes (TDL) did not reduce the response of PBL to PHA, neither did cell crowding. The supernatants from 24-h cultures of m/c-treated PBL did not affect the response to PHA, and parallelly precultured cells inhibited the proliferation of PBL to a lesser degree (24 +/- 9%) than the fresh cells (50 +/- 16%, P less than 0.05). Addition of m/c-treated polymorphonuclear cells at PMN to PBL ratios of 1:4 and 1:1 progressively inhibited PBL reactivity to PHA, from 29.5 +/- 3.5% to 68.5 +/- 9%, respectively, and the supernatants from 24-h cultures of PMN reduced the proliferation by 48 +/- 2.8%. The neutrophil-derived inhibitory factor(s) was non-cytotoxic and reduced the formation of blasts to 61.5 +/- 3.5% of the control values. These results indicate that dog PBL from Lymphoprep gradient contain a population of non-recirculating, short-lived, spontaneously suppressive cells, mainly PMN, which modulate T cell reactivity in vitro, suggesting that neutrophils may be able to exert a regulatory effect in vivo.
authors.affiliation: Department of Surgical Research and Transplantation, Polish Academy of Sciences, Warsaw.
authors.forename: H
authors.initials: H
authors.lastname: Galkowska
authors.forename: M
authors.initials: M
authors.lastname: Dabrowski
authors.forename: W L
authors.initials: WL
authors.lastname: Olszewski
mesh_terms: D000818:Animals; D004285:Dogs / Q000097:blood / Q000276:immunology*; D005260:Female; D007108:Immune Tolerance; D007111:Immunity, Cellular; D007213:Indomethacin / Q000494:pharmacology; D007962:Leukocytes / Q000187:drug effects / Q000276:immunology*; D008213:Lymphocyte Activation; D008297:Male; D009504:Neutrophils / Q000276:immunology; D010835:Phytohemagglutinins / Q000494:pharmacology
chemical_list: D010835:Phytohemagglutinins; D007213:Indomethacin