Epithelial cell pro-inflammatory cytokine response differs across dental plaque bacterial species

Aim: The dental plaque is comprised of numerous bacterial species, which may or may not be pathogenic. Human gingival epithelial cells (HGECs) respond to perturbation by various bacteria of the dental plaque by production of different levels of inflammatory cytokines, which is a putative reflection of their virulence. The aim of the current study was to determine responses in terms of interleukin (IL)-1β, IL-6, IL-8 and IL-10 secretion induced by Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and Streptococcus gordonii in order to gauge their virulence potential. Materials and Methods: HGECs were challenged with the four bacterial species, live or heat killed, at various multiplicity of infections and the elicited IL-1β, IL-6, IL-8 and IL-10 responses were assayed by enzyme-linked immunosorbent assay. Results: Primary HGECs challenged with live P. gingivalis produced high levels of IL-1β, while challenge with live A. actinomycetemcomitans gave high levels of IL-8. The opportunistic pathogen F. nucleatum induces the highest levels of pro-inflammatory cytokines, while the commensal S. gordonii is the least stimulatory. Conclusion: We conclude that various dental plaque biofilm bacteria induce different cytokine response profiles in primary HGECs that may reflect their individual virulence or commensal status.