title: Comparative study of respiratory burst induced by phorbol ester and zymosan in human granulocytes.
abstract: OBJECTIVE
  We have comparatively evaluated respiratory burst and some steps of its signaling in human granulocytes towards different stimuli.
  
  
  METHODS
  An alternative method to remove erythrocytes by dextran differential sedimentation was employed. Respiratory burst (RB) was assessed in a flow cytometer by the oxidation of a fluorescent probe (dichlorodihydrofluorescein). Stimuli were phorbol ester (PMA) and zymosan.
  
  
  RESULTS
  Granulocytes obtained with dextran sedimentation mounted a normal RB for the two stimuli but cells obtained by erythrocyte lysis were ineffective to respond to zymosan (P < 0.05). EGTA did not affect PMA-induced, but inhibited zymosan-induced RB (P < 0.05). PMA-induced RB was blocked by a protein kinase C inhibitor (P < 0.05), whereas zymosan was not. Microfilament integrity was essential for zymosan but not for PMA, whereas microtubule depolymerization does not seem to be essential for both stimuli. Granulocytes obtained from recently diagnosed leukemia patients responded relatively well to both stimuli but after chemotherapy, the response to zymosan was increased whereas cells were unable to respond to PMA.
  
  
  CONCLUSIONS
  The use of the proposed method allows the study of both RB and phagocytosis, making it useful to study these granulocyte responses in the clinical and experimental settings.
authors.affiliation: Department of Immunology, Centre of Biological Sciences, UFSC, Brazil.
authors.forename: Fabiane
authors.initials: F
authors.lastname: Lunardi
authors.forename: José Hermênio Cavalcante
authors.initials: JH
authors.lastname: Lima
authors.forename: Jamil
authors.initials: J
authors.lastname: Assreuy
mesh_terms: D000328:Adult; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D003078:Colchicine / Q000494:pharmacology; D015638:Cytochalasin D / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects; D004912:Erythrocytes; D005260:Female; D005434:Flow Cytometry; D006098:Granulocytes / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007938:Leukemia / Q000378:metabolism; D007962:Leukocytes / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D017239:Paclitaxel / Q000494:pharmacology; D010703:Phorbol Esters / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D016897:Respiratory Burst / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects; D015054:Zymosan / Q000494:pharmacology*
chemical_list: D010703:Phorbol Esters; D015638:Cytochalasin D; D015054:Zymosan; D011493:Protein Kinase C; D017239:Paclitaxel; D003078:Colchicine; D002118:Calcium