Variability of the Dendritic Cell Response Triggered by Different Serotypes of Aggregatibacter actinomycetemcomitans or Porphyromonas gingivalis Is Toll‐Like Receptor 2 (TLR2) or TLR4 Dependent

Abstract

These results demonstrate that the variability of secretion of cytokines and expression of CCRs detected in DCs stimulated with different serotypes of A. actinomycetemcomitans or P. gingivalis is TLR2 or TLR4 dependent, respectively.

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

“…This structural variability in the LPS among the different A. actinomycetemcomitans serotypes has been associated with a differential toll‐like receptor (TLR)‐dependent recognition in DCs. Indeed, although the serotypes a , b , and c of A. actinomycetemcomitans lead to similar upregulation of TLR4, higher overexpressed levels of TLR2 were detected in serotype b ‐stimulated DCs compared with the same cells stimulated with the other serotypes (Díaz‐Zúñiga, Monasterio, et al, ). Furthermore, when the TLR2 signaling was blocked using a specific anti‐TLR2 neutralizing monoclonal antibody, the serotype b ‐induced cytokine expression was inhibited (Díaz‐Zúñiga, Monasterio, et al, ).…”

“…Indeed, although the serotypes a , b , and c of A. actinomycetemcomitans lead to similar upregulation of TLR4, higher overexpressed levels of TLR2 were detected in serotype b ‐stimulated DCs compared with the same cells stimulated with the other serotypes (Díaz‐Zúñiga, Monasterio, et al, ). Furthermore, when the TLR2 signaling was blocked using a specific anti‐TLR2 neutralizing monoclonal antibody, the serotype b ‐induced cytokine expression was inhibited (Díaz‐Zúñiga, Monasterio, et al, ). These data allow us to suggest that the differential production of IFN‐γ, CRP, MMP‐2, and MMP‐9 detected in DCs stimulated with the different serotypes of A. actinomycetemcomitans could be, at least partly, TLR2‐dependent.…”

“…Indeed, seven distinct serotypes are recognized for A. actinomycetemcomitans based on the differential antigenicity of the O‐polysaccharide component of their lipopolysaccharide (LPS) (Takada et al, ). These A. actinomycetemcomitans serotypes differ in their ability to induce response in host immune cells; in particular, serotype b induces higher levels of Th1 and Th17 types of cytokines in DCs compared with the other serotypes (Díaz‐Zúñiga, Monasterio, et al, ; Díaz‐Zúñiga et al, ). Interestingly, although most of the periodontitis patients being positive for A. actinomycetemcomitans harbor only one serotype within the subgingival biofilm, several studies have reported that 15%–33% of these patients harbor two or three different A. actinomycetemcomitans serotypes in the same sampled periodontal pocket (Minguez et al, ; Roman‐Torres et al, ; Rylev & Kilian, ; Saarela et al, 1992; van der Reijden, Bosch‐Tijhof, van der Velden, & van Winkelhoff, ).…”

Porphyromonas gingivalis promotes the cell cycle and inflammatory cytokine production in periodontal ligament fibroblasts

“…6 Infection by P. gingivalis could modulate host immune-inflammatory responses and ultimately destroy the balance of the normal cell cycle and apoptosis, thereby leading to periodontal tissue destruction. [7][8][9] The cell cycle is the key step in cell proliferation, differentiation and senescence in multicellular tissues. Pathogens damaging DNA structures could promote G1 phase arrest until the repair of DNA ensued.…”

Mitogen-Activated Protein Kinase 2 Signaling Shapes Macrophage Plasticity in Aggregatibacter actinomycetemcomitans-Induced Bone Loss

“…Aggregatibacter actinomycetemcomitans possesses several virulence factors, including leukotoxin, cytolethal distending toxin (CDT), and lipopolysaccharide (LPS), which have potent immunomodulatory effects. It is thought that serotype b strains of A. actinomycetemcomitans are highly virulent and have potent LPS endotoxin and leukotoxin, which are responsible for significantly increasing the host response compared to the host response to other serotypes of A. actinomycetemcomitans (15,19).…”