Inhibitory effect of serotype a of Aggregatibacter actinomycetemcomitans on the increased destructive potential of serotype b

Leticia Rojas, Samanta Melgar-Rodríguez, Jaime Díaz-Zúñiga, Carla Alvarez, Gustavo Monasterio, Carolina Rojas, Emilio A. Cafferata, Marcela Hernández, Cristian Cortéz, Paola Carvajal, Rolando Vernal

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Objective: The serotype b of Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) induces higher cytokine production in dendritic cells (DCs) compared with the other serotypes. However, this increased immunostimulatory potential was modified when DCs were co-infected with the other A. actinomycetemcomitans serotypes. This study aimed to analyze whether the production of interferon gamma (IFN-γ), C-reactive protein (CRP), matrix metalloproteinase (MMP)-2, and MMP-9, as well as the activity of osteoclasts, also varies when DCs are co-infected with the A. actinomycetemcomitans serotypes. Materials and Methods: Human DCs were stimulated with the A. actinomycetemcomitans serotypes using the following stimulatory conditions: serotype a/b/c/a+b/a+c/b+c/a+b+c. The IFN-γ, CRP, and MMP-2 levels were quantified by ELISA. The active form of MMP-9 was quantified using fluorescent functional assays. The MMP-2 gelatinolytic activity was identified by zymogram. The osteoclast activity was determined by quantifying the TRAP expression and resorption-pit formation using cytochemistry and osteoassays. Results: Higher levels of IFN-γ, CRP, MMP-2, MMP-9, and osteoclast activity were detected when DCs were stimulated with the serotype b of A. actinomycetemcomitans compared with the others. This increased immunostimulatory potential attributed to serotype b diminished when DCs were co-infected with the serotype a. Conclusions: This study provides new insights into the virulence of A. actinomycetemcomitans and reveals important differences in the immunostimulatory and pro-destructive potential among its serotypes.

Original languageEnglish
Pages (from-to)409-418
Number of pages10
JournalOral Diseases
Issue number2
StatePublished - 1 Mar 2020


  • A. actinomycetemcomitans
  • bone resorption
  • cytokines
  • matrix metalloproteinases
  • osteoclasts
  • serotypes


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