Serotype‐dependent response of human dendritic cells stimulated with Aggregatibacter actinomycetemcomitans

Abstract

Aggregatibacter actinomycetemcomitans strains belonging to the serotype b demonstrated a higher capacity to trigger Th1 and Th17-type cytokine production on DCs. These increased potential is likely explained by a higher immunogenicity of their LPS.

T‐lymphocyte phenotype and function triggered by Aggregatibacter actinomycetemcomitans is serotype‐dependent

“…The monocyte and DC purities were demonstrated by flow cytometry using a combined staining with the following mAbs: anti‐CD14 (marker of monocytes), CD1a (marker of immature DCs), CD83 (marker of mature DCs), CD80 and CD86 (co‐stimulatory signals necessary for T‐cell activation during antigenic presentation, used as markers of DCs stimulation). Similarly to our previous experiments , a highly purified (>98%) monocyte population was isolated from peripheral blood and, upon culture in presence of IL‐4 and granulocyte‐macrophage colony‐stimulating factor, these monocytes differentiated at a high frequency (>97%) into DCs (Fig. A).…”

“…LPS purified from the different A. actinomycetemcomitans serotypes was prepared as previously described . A. actinomycetemcomitans strains were cultured in liquid brain–heart infusion medium until they reached the stationary growth phase and then incubated in 3 mL of 5:1 TRIzol reagent (Invitrogen, Barcelona, Spain) and chloroform (Fluka; Sigma‐Aldrich Chemie GmbH, Buchs, Switzerland) at room temperature for 30 min.…”

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

“…The A. actinomycetemcomitans strains ATCC ® 43717™ (serotype a ), ATCC ® 43718™ (serotype b ), and ATCC ® 43719™ (serotype c ) were cultured on agar brain–heart infusion medium as previously described (Díaz‐Zúñiga et al, ). In order to obtain a reliable number of live bacteria having their whole antigenic potentiality for DC infection, bacterial growth curves were made using standard procedures and bacteria were taken at the exponential growth phase (Vernal et al, ).…”

“…Aggregatibacter actinomycetemcomitans ( A. actinomycetemcomitans ) is a highly pathogenic bacteria strongly associated with the etiology of periodontitis (Schacher et al, ); however, not all bacteria strains belonging to the A. actinomycetemcomitans species have the same immunogenicity (Díaz‐Zúñiga, Melgar‐Rodríguez, et al, ; Díaz‐Zúñiga et al, ; Melgar‐Rodríguez et al, ; Monasterio et al, ). 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, ).…”

“…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, ).…”