title: Porphyromonas gingivalis antigens differently participate in the proliferation and cell death of human PBMC.
abstract: OBJECTIVE
  Modulation of cell-mediated immunity by microorganisms in periodontal diseases has been widely studied; however, the proliferative activity and/or programmed death of mononuclear cells under periodontopathogenic stimuli are not yet well understood. The aim of this study was to investigate in vitro proliferation and death of peripheral blood mononuclear cells (PBMC) upon stimulation with Porphyromonas gingivalis (Pg) antigens.
  
  
  METHODS
  In 19 patients with chronic periodontitis (CP) and 16 controls without periodontitis (NP) the following clinical parameters were evaluated: bleeding on probing, probing depth, and clinical attachment level. PBMC were cultured under Pg stimuli and apoptosis/necrosis and proliferation assays were carried out for 18 and 48 h, respectively. Fluorescence of labelled cells was determined using flow cytometry.
  
  
  RESULTS
  PBMC of CP and NP subjects exhibited a lower proliferative response to Pg LPS (p<0.05) and HmuY protein (p<0.001) compared with non-stimulated cells. Early apoptosis was induced by Pg LPS (p<0.01) and Pg extract (p<0.05), whilst all antigens induced late apoptosis (Pg LPS: p<0.001; Pg extract: p<0.001; HmuY: p<0.01) and necrosis (Pg LPS: p<0.01; Pg extract: p<0.001; HmuY: p<0.001). Pg LPS induced higher late apoptosis than HmuY (p<0.05). Only Pg LPS-induced necrosis tended to be higher in CP compared with NP.
  
  
  CONCLUSIONS
  The inhibitory effect of cell proliferation caused by Pg LPS and HmuY protein is not observed when these antigens comprise Pg extract. Despite induced apoptosis, some still unknown mechanism determines the inflammatory outcome in cell death stimulated by HmuY.
authors.affiliation: Laboratory of Immunology, Health Sciences Institute, Federal University of Bahia, Brazil. soraya@uefs.br
authors.forename: Soraya C
authors.initials: SC
authors.lastname: Trindade
authors.forename: Teresa
authors.initials: T
authors.lastname: Olczak
authors.forename: Isaac S
authors.initials: IS
authors.lastname: Gomes-Filho
authors.forename: Lilia F
authors.initials: LF
authors.lastname: Moura-Costa
authors.forename: Vera L
authors.initials: VL
authors.lastname: Vale
authors.forename: Milton
authors.initials: M
authors.lastname: Galdino-Neto
authors.forename: Heidiane
authors.initials: H
authors.lastname: Alves
authors.forename: Paulo C
authors.initials: PC
authors.lastname: Carvalho-Filho
authors.forename: Geraldo P
authors.initials: GP
authors.lastname: Sampaio
authors.forename: Márcia T
authors.initials: MT
authors.lastname: Xavier
authors.forename: Viviane A
authors.initials: VA
authors.lastname: Sarmento
authors.forename: Roberto
authors.initials: R
authors.lastname: Meyer
mesh_terms: D016022:Case-Control Studies; D016923:Cell Death / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects*; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010518:Periodontitis / Q000097:blood / Q000276:immunology*; D016966:Porphyromonas gingivalis / Q000276:immunology*