ENHANCEMENT OF GROWTH OF PERIODONTOPATHIC BACTERIA BY PRO-INFLAMMATORY CYTOKINES

1994 Fiscal Year Final Research Report Summary

• Project/Area Number: 05671520
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Morphological basic dentistry
• Research Institution: NIHON UNIVERSITY
• Principal Investigator: OCHIAI Tomoko NIHON UNIVERSITY,SCHOOL OF DENTISTRY AT MATSUDO,INSTRUCTER, 松戸歯学部, 助手 (20130594)
• Co-Investigator(Kenkyū-buntansha): OCHIAI Kuniyasu NIHON UNIVERSITY,SCHOOL OF DENTISTRY AT MATSUDO,ASSISTANT PROFESSOR, 松戸歯学部, 講師 (50095444) ; FUKUSHIMA Kazuo NIHON UNIVERSITY,SCHOOL OF DENTISTRY AT MATSUDO,PROFESSOR, 松戸歯学部, 教授 (20009327)
• Project Period (FY): 1993 – 1994
• Keywords: Growth / Periodontopathic bacteria / IL-1alpha / IL-1beta / IL-6

Research Abstract

(1) Effect of cytokines on bacteria growth : we investigated the effect of IL-alpha, beta and IL-6 on bacterial growth. The growth-promoting effect of IL-1alpha, beta over control (no IL-1) was observed during the log phase of Actinobacillus growth (9h : 1.6-1.9 times, 18th : 1.5-1.7 times) . IL-1 alpha at 1 to 100 ng/ml enhanced Actinobacillus growth after 9h incubation compared to control. IL-1beta at 10 and 100 ng/ml promoted Actinobacillus growth. IL-1 alpha, beta also had a smaller effect on Capnocytophaga and Fusobacterium growth.
(2) Binding of ^<125>I-IL-1alpha, beta and IL-6 to bacteria : Actinobacillus showed a high level of uptake of the radiolabeled IL-1alpha, beta and IL-6, While Capnocytophaga and Fusobacterium bound a very low amount of ^<125>I-IL-1alpha and IL-6. Other strains including Porphyromonas, Prevotella and Eikenella did not bind to cytokines.
(3) Homology search with human cytokine receptor gene : When we examined bacteria for gene expression of cytokine receptor, expression of IL-IR (I) and IL-IR (II) was only detected in Actinobacillus, not other bacteria such as Porphyromonas, Prevotella, Fusobacterium and Capnocytophaga. On the other hand, IL-6R expression was not detected in all the strains used.
(4) Autocrine mechanism against bacteria : We examined IL-Ialpha, beta and IL-6 cytokine activity in bacterial culture supernatants. IL-1alpha activity was detected slightly in Fusobacterium and Capnocytophaga, but was not significant. Trace amounts of IL-I beta ware detected in all the strains used, and especially higher level of IL-I beta could be detected in Actinobacillus. IL-6 was not produced in all the strains.