title: T-lymphocyte phenotype and function triggered by Aggregatibacter actinomycetemcomitans is serotype-dependent.
abstract: OBJECTIVE
  Based on lipopolysaccharide (LPS) antigenicity, different Aggregatibacter actinomycetemcomitans serotypes have been described. Serotype b strains have demonstrated a stronger capacity to trigger cytokine production on dendritic cells (DCs). As DCs regulate the development of T-lymphocyte lineages, the objective of this investigation was to study the response of T lymphocytes after being stimulated with autologous DCs primed with different bacterial strains belonging to the most prevalent serotypes of A. actinomycetemcomitans in humans: a-c.
  
  
  METHODS
  Human DCs were primed with increasing multiplicity of infection (10(-1) -10(2) ) or the purified LPS (10-50 ng/mL) of A. actinomycetemcomitans serotypes a-c and then used to stimulate autologous naïve CD4(+) T lymphocytes. The T-helper (Th) type 1, Th2, Th17 and T-regulatory transcription factors T-bet, GATA-3, RORC2 and Foxp3, which are the master-switch genes implied in their specific differentiation, as well as T-cell phenotype-specific cytokine patterns were quantified by real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. In addition, the intracellular expression of T-bet/interferon-γ, GATA-3/interleukin-4, RORC2/interleukin-17A and Foxp3/transforming growth factor-β1 was analysed by double staining and flow cytometry.
  
  
  RESULTS
  All the A. actinomycetemcomitans serotypes led to T-lymphocyte activation; however, when T lymphocytes were stimulated with DCs primed with the A. actinomycetemcomitans serotype b strain or their purified LPS, higher levels of Th1- and Th17-associated transcription factors and cytokines were detected compared with similar experiments with the other serotypes.
  
  
  CONCLUSIONS
  These results demonstrate that serotype b of A. actinomycetemcomitans has a higher capacity of trigger Th1 and Th17 phenotype and function and it was demonstrated that their LPS is a more potent immunogen compared with the other serotypes.
authors.affiliation: Periodontal Biology Laboratory, Dental School, Universidad de Chile, Santiago de Chile, Chile.|Department of Conservative Dentistry, Dental School, Universidad de Chile, Santiago de Chile, Chile.
authors.forename: J
authors.initials: J
authors.lastname: Díaz-Zúñiga
authors.affiliation: Periodontal Biology Laboratory, Dental School, Universidad de Chile, Santiago de Chile, Chile.|Department of Conservative Dentistry, Dental School, Universidad de Chile, Santiago de Chile, Chile.
authors.forename: S
authors.initials: S
authors.lastname: Melgar-Rodríguez
authors.affiliation: Periodontal Biology Laboratory, Dental School, Universidad de Chile, Santiago de Chile, Chile.
authors.forename: C
authors.initials: C
authors.lastname: Alvarez
authors.affiliation: Periodontal Biology Laboratory, Dental School, Universidad de Chile, Santiago de Chile, Chile.
authors.forename: G
authors.initials: G
authors.lastname: Monasterio
authors.affiliation: Periodontal Biology Laboratory, Dental School, Universidad de Chile, Santiago de Chile, Chile.
authors.forename: A
authors.initials: A
authors.lastname: Benítez
authors.affiliation: Periodontal Biology Laboratory, Dental School, Universidad de Chile, Santiago de Chile, Chile.
authors.forename: P
authors.initials: P
authors.lastname: Ciuchi
authors.affiliation: Department of Conservative Dentistry, Dental School, Universidad de Chile, Santiago de Chile, Chile.
authors.forename: C
authors.initials: C
authors.lastname: Díaz
authors.affiliation: Department of Conservative Dentistry, Dental School, Universidad de Chile, Santiago de Chile, Chile.
authors.forename: J
authors.initials: J
authors.lastname: Mardones
authors.affiliation: Dental Sciences Institute, Dental School, Universidad de Chile, Santiago de Chile, Chile.
authors.forename: A
authors.initials: A
authors.lastname: Escobar
authors.affiliation: ETEP (Etiology and Therapy of Periodontal Diseases) Research Group, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Sanz
authors.affiliation: Periodontal Biology Laboratory, Dental School, Universidad de Chile, Santiago de Chile, Chile.|Department of Conservative Dentistry, Dental School, Universidad de Chile, Santiago de Chile, Chile.
authors.forename: R
authors.initials: R
authors.lastname: Vernal
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000145:classification / Q000276:immunology*; D002478:Cells, Cultured; D016207:Cytokines / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D006801:Humans; D016130:Immunophenotyping; D008070:Lipopolysaccharides / Q000276:immunology; D010641:Phenotype; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D065288:Serogroup; D013601:T-Lymphocytes / Q000276:immunology*; D014157:Transcription Factors / Q000032:analysis
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D014157:Transcription Factors
keywords: Aggregatibacter actinomycetemcomitans; T lymphocytes; cytokines; lipopolysaccharide; serotypes; transcription factors