Augmentation of Actinobacillus actinomycetemcomitans invasion of human oral epithelial cells and up-regulation of interleukin-8 production by saliva CD14

Atsuko Takayama, Aya Satoh, Tomoko Ngai, Takashi Nishimura, Keiji Ikawa, Takami Matsuyama, Hidetoshi Shimauchi, Haruhiko Takada, Shunji Sugawara

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

It has recently been shown that human salivary glands constitutively express CD14, an important molecule in innate immunity, and that a soluble form of CD14 is secreted in saliva. The concentration of CD14 in parotid (a serous gland) saliva was comparable to that in normal serum and 10-fold the amount in whole saliva, although the physiological function of saliva CD14 remained unclear. Actinobacillus actinomycetemcomitans is a periodontopathic bacterium and is able to invade oral epithelial cells. The present study showed that upon exposure to live A. actinomycetemcomitans Y4 for 2 h, human oral epithelial HSC-2 cells produced interleukin-8 (IL-8) for a further 24 h and whole saliva augmented the production induced by A. actinomycetemcomitans Y4. Parotid saliva showed a more pronounced effect on the production of IL-8 than whole saliva. Neither saliva preparation itself had IL-8-inducing activity. Parotid saliva exhibited antibacterial activity against a low concentration of A. actinomycetemcomitans Y4, but recombinant CD14 did not show the activity. The internalization of A. actinomycetemcomitans Y4 into HSC-2 cells was inhibited by cytochalasin B, indicating that the process was actin dependent, and depletion of CD14 from parotid saliva inhibited the invasion and, as a consequence, inhibited production of IL-8. Furthermore, human recombinant CD14 augmented invasion and IL-8 production. These results suggest that saliva CD14 promoted the invasion of oral epithelial cells by A. actinomycetemcomitans and consequently augmented the production of IL-8, playing an important role in innate immunity in the oral cavity.

Original languageEnglish
Pages (from-to)5598-5604
Number of pages7
JournalInfection and immunity
Volume71
Issue number10
DOIs
Publication statusPublished - 2003 Oct 1

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases

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