不同fimA基因型牙龈卟啉单胞菌对牙龈成纤维细胞表达白细胞介素-8的影响

目的:研究不同fimA基因型牙龈卟啉单胞菌(Porphyromonas gingivalis, Pg)对人牙龈成纤维细胞表达IL- 8的影响,探讨fimA基因型与Pg致病力差异之间的关系.方法: Pg ATCC 33277(Ⅰ型),WCSP115(Ⅱ型),WCSP1.5(Ⅲ型),W83(Ⅳ型)分别与牙龈成纤维细胞在标准条件下共同孵育,于孵育后1、3、6、12 h收集细胞和上清,应用实时荧光定量RT- PCR和ELISA法分别检测牙龈成纤维细胞IL- 8 mRNA和蛋白的动态表达.结果:与对照组比较,各fimA型Pg对牙龈成纤维细胞IL- 8 mRNA和蛋白的表达均有明显的促进作用(P<0.01);其中ⅡfimA型组IL- 8 mRNA和蛋白的表达量明显高于其它fimA型组,不同时间点IL- 8 mRNA相对表达量分别为20.42±2.21～103.01±12.50,蛋白分泌水平为(137.46±4.97～323.24±13.74) pg/ml;而Ⅲ fimA型Pg组的表达水平弱于其它fimA型组,IL- 8 mRNA相对表达量为3.61±0.39～12.88±1.56,蛋白分泌水平为(44.83±3.68～189.19±87.34) pg/ml, 差异有统计学意义(P<0.05).结论:Pg可促进牙龈成纤维细胞IL- 8 mRNA和蛋白的表达,且各fimA型Pg的促进作用有所差异.提示: fimA基因型的不同可能是Pg的致病力差异的基因基础.     

不同fimA基因型牙龈卟啉单胞菌刺激口腔上皮细胞白细胞介素-8的表达

目的比较不同fimA基因型牙龈卟啉单胞菌（P.gingivalis）刺激下口腔上皮细胞白细胞介素-8（IL-8）的表达水平,初步探讨P.gingivalis致病性与其fimA基因型的关系。方法P.gingivalis ATCC 33277（Ⅰ型fimA）、W83、47A-1（Ⅳ型fimA）和KB细胞ATCC CCL-17共同孵育24 h,以未受刺激的KB细胞作为对照组,分别在1、3、6、24 h收集细胞和培养上清液。RT-PCR检测KB细胞IL-8 mRNA的动态表达,酶联免疫反应检测培养上清液中IL-8的动态变化。结果2种fimA基因型菌株刺激1 h,KB细胞IL-8 mRNA的表达上调至峰值,高于对照组,3~24 h IL-8 mRNA的表达水平接近对照组;P.gingivalis感染细胞后3~24 h,上清液中的IL-8水平低于对照组,Ⅳ型菌株低于Ⅰ型菌株;IL-8 mRNA及其蛋白表达不完全一致,提示IL-8的表达存在转录后水平的调节。结论fimA基因型与口腔上皮细胞IL-8的表达水平相关,提示P.gingivalis致病性与其fimA基因型相关。     

CD-14和Tool样受体在牙髓卟啉单胞菌脂多糖诱导成骨细胞白细胞介素6表达中的作用

目的 探讨CD-14和Tool样受体（Toll like receptors,TLR）在牙髓卟啉单胞菌（Porphyromonas endodontalis,Pe）脂多糖诱导小鼠成骨细胞白细胞介素6(IL-6)表达中的作用。方法用10 mg/L的Pe-脂多糖分别作用于小鼠成骨细胞MC3T3-E1不同时间,未加Pe-脂多糖的MC3T3-E1为空白对照组。反转录聚合酶链反应(RT-PCR)和酶联免疫吸附试验检测细胞IL-6基因和蛋白的表达,RT-PCR和流式细胞术检测细胞表面CD-14、TLR-2及TLR-4基因和蛋白的表达变化。抗小鼠CD-14、TLR-2及TLR-4抗体预处理细胞后,采用RT-PCR法检测Pe-脂多糖诱导细胞IL-6mRNA表达的变化。应用SPSS 11.0统计软件对结果进行单因素方差分析Dunnett-t检验。结果Pe-脂多糖作用于细胞后,与空白对照组比较细胞IL-6 mRNA和蛋白的表达明显增加,6h时IL-6表达[(36.534±0.574) ng/L]显著高于空白对照组[(11.696±0.672)ng/L)],P＜O.01;空白对照组中CD-14和TLR-4 mRNA呈弱表达,CD-14和TLR-4的阳性细胞率分别为(39.038±3.131)％和( 11.438±0.385)％,加入Pe-脂多糖后CD-14和TLR-4 mRNA表达明显增加,CD-14和TLR-4的阳性细胞率分别增加至(62.407±1.800)％和(21.367±2.271)％,但TLR-2的表达未见明显变化;中和抗体实验证明CD-14或TLR-4抗体均可部分抑制细胞IL-6 mRNA的表达,TLR-2抗体则无此作用。结论Pe-脂多糖作用于成骨细胞MC3T3-E1诱导其炎症因子IL-6的产生依赖于CD-14和TLR-4受体,与TLR-2无关。     

牙龈卟啉单胞菌对兔血管内皮组织中白细胞介素-33表达的影响

目的 用牙龈卟啉单胞菌感染兔建立动脉粥样硬化（AS）模型,观察感染兔主动脉血管内皮细胞中白细胞介素-33（IL-33）的变化,探讨牙龈卟啉单胞菌与AS的关系。方法 将24只新西兰大白兔分为对照组和实验组。实验组每周1次静脉注射牙龈卟啉单胞菌培养液,持续12周,建立感染兔AS模型;对照组每周1次注射等量生理盐水。实验13周处死实验动物,观察主动脉血管的组织结构;通过免疫组织化学染色、实时荧光半定量聚合酶链式反应和Western blot法检测兔主动脉血管内皮细胞中IL-33 mRNA和蛋白质的表达。结果 实验组血管内皮细胞IL-33 mRNA相对表达量为58.244±2.407,IL-33蛋白相对表达量为1.863±0.171,对照组IL-33 mRNA相对表达量为3.143±0.805,IL-33蛋白相对表达量为0.537±0.028;实验组IL-33的mRNA和蛋白的表达量均明显高于对照组（P<0.01）。结论 牙龈卟啉单胞菌感染能促进血管内皮细胞表达IL-33,可能对AS的发生发展有一定的调节作用。     

牙髓卟啉单胞菌脂多糖诱导小鼠成骨细胞表达白细胞介素-23

目的：探讨牙髓卟啉单胞菌（P．e）脂多糖（LPS）对小鼠成骨细胞 IL-23mRNA 和蛋白表达的影响,以及磷脂酰肌醇-3激酶（PI3K）信号通路是否参与了该过程。方法：采用 real-time PCR 和 Western blot 法检测 P．e LPS 诱导 MC3T3-E1细胞表达IL-23mRNA 和蛋白的情况,以及用 PI3K 信号通路抑制剂 LY294002预处理细胞后,IL-23mRNA 和蛋白表达的变化。结果：P．e LPS 刺激 MC3T3-E1细胞后,IL-23mRNA 的表达增加具有浓度依赖性和时间依赖性（P ＜0．05）,IL-23蛋白的表达增加具有时间依赖性（P ＜0．05）;LY294002预处理细胞后,P．e LPS 诱导的 IL-23mRNA 和蛋白的表达均显著降低（P ＜0．05）。结论：P．e LPS 能诱导小鼠成骨细胞表达 IL-23mRNA 和蛋白,PI3K 信号通路可能参与了此过程。     

骨化三醇对牙龈卟啉单胞菌脂多糖诱导的人牙周膜细胞IL-8、IL-6表达的影响研究

目的    观察活性形式的维生素D——骨化三醇（1,25D）对牙龈卟啉单胞菌脂多糖（Pg-LPS）诱导的人牙周膜细胞（hPDLCs）白细胞介素（IL）-8、IL-6表达的影响。方法    取3例患者因正畸需要拔除的前磨牙牙周膜,组织块法原代培养hPDLCs,分别用0.1%无水乙醇（对照组）、10 μg/mL Pg-LPS（单纯Pg-LPS组）、10-10 mol/L 1,25D（低浓度1,25D组）、10-8 mol/L 1,25D（高浓度1,25D组）、10-10mol/L 1,25D+ 10 μg/mL Pg-LPS（低浓度1,25D联合Pg-LPS组）、10-8mol/L 1,25D+ 10 μg/mL Pg-LPS（高浓度1,25D联合Pg-LPS组）处理第5代细胞。24和48 h后收集培养基上清液,酶联免疫吸附试验（ELISA）法检测hPDLCs IL-8和IL-6的表达水平。结果    （1）10 μg/mL Pg-LPS处理hPDLCs 48 h时,其IL-8表达水平最高,为对照组的38.86倍（P＜0.001）;处理hPDLCs 24 h时,其IL-6表达水平最高,为对照组的 6.19倍（P＜0.001）。（2）1,25D 以剂量和时间依赖方式抑制hPDLCs IL-8的内源性表达。10-8 mol/L 1,25D 处理hPDLCs 48 h时,其IL-8表达水平为对照组的49.94%（P＜0.001）。（3）1,25D 显著抑制Pg-LPS诱导的hPDLCs IL-8和IL-6的表达。处理48 h时,高浓度1,25D联合Pg-LPS组hPDLCs IL-8的表达水平为单纯Pg-LPS组的71.98%（P＜0.001）;处理24 h时,高浓度1,25D联合Pg-LPS组hPDLCs IL-6的表达水平为单纯Pg-LPS组的84.51%（P = 0.003）。结论    1,25D可以抑制hPDLCs IL-8的内源性表达,并抑制Pg-LPS诱导的hPDLCs IL-8和IL-6的表达,从而可能抑制牙周炎症反应。     

牙龈卟啉单胞菌与龈沟液中白细胞介素8关系的研究

目的:探讨龈沟液(GCF)中白细胞介素8(IL -8)在慢性牙周炎病程中的变化、IL- 8与牙周临床检测指标以及同龈下菌斑中细菌含量的相关关系。方法: 5名非牙周炎患者的10颗牙周健康牙和30名慢性牙周炎(CP)患者的70颗牙(其中10颗为健康牙, 60颗为牙周炎患牙)纳入本研究。采集观察牙的GCF样本、龈下菌斑样本,同时记录所有牙的牙龈指数(GI)、牙周袋探诊深度(PPD)、临床附着丧失水平(CAL)。用ELISA法检测样本中IL -8的水平,用厌氧菌培养技术培养菌斑标本,用PCR法检测菌斑中的牙龈卟啉单胞菌(Pg),结果:慢性牙周炎组的GCF中IL -8的总量高于临床牙周健康组,而IL -8的质量浓度在各组中无差异。GCF中IL- 8浓度与GI、PPD、CAL无相关关系,而IL -8的总量与GI、PPD、CAL呈正相关关系。龈下菌斑中Pg的检出量与GCF中IL- 8的含量间未发现有相关关系。结论:慢性牙周炎患者龈沟液中IL- -8量增加与龈沟液分泌增加有关而与牙龈卟啉单胞菌检出CFU无关。     

NF-κB在牙髓卟啉单胞菌脂多糖诱导小鼠成骨细胞白介素6表达中的作用

目的:探讨核因子κB(NF-κB)在牙髓卟啉单胞菌(P.e)脂多糖(LPS)诱导小鼠成骨细胞株MC3T3-El白介素6(IL-6)表达中的作用。方法：10 mg/L P.e -LPS刺激MC3T3-El细胞不同时间后,应用免疫荧光方法检测NF-κB核易位情况和BAY-117082对NF-κB核易位抑制情况,反转录聚合酶链反应(RT—PCR)和酶联免疫吸附试验(ELISA)检测BAY-117082对MC3T3-El细胞的IL-6基因和蛋白表达的影响。采用SPSS 13.0软件包对结果进行多因素方差分析和Dunnett t检验。结果：在静息状态下,NF-κB 定位在胞质中,10 mg/L P.e-LPS刺激MC3T3-El细胞30 min后即引起NF-κB快速的核易位;60 min后,大部分NF-κB重新定位在胞质里,10 μmol/L BAY-117082预处理1 h可抑制 P.e-LPS引起的NF-κB核易位,降低P.e-LPS诱导MC3T3-El细胞IL-6 mRNA表达水平和IL-6蛋白的分泌水平,其中,蛋白分泌水平从(774.983±6.585) ng/L降低至 (377.384±14.620) ng/L(P<0.O1),而BAY-117082单独刺激组与空白对照组无显著差异。结论：P.e-LPS可诱导MC3T3-El细胞中NF-κB的核易位,P.e-LPS可通过激活NF-κB信号途径诱导MC3T3-El细胞产生IL-6。     

牙龈卟啉单胞菌PG0839基因对小鼠肝细胞和血清中IL-1β与IL-6表达影响研究

目的 探讨牙龈卟啉单胞菌（Porphyromonas gingivalis,P.gingivalis）PG0839基因对小鼠肝细胞和血清中炎症因子白细胞介素1β（IL-1β）与白细胞介素6（IL-6）表达的影响,以期为进一步明确该基因的功能提供实验依据。方法 本研究于2013年6—12月在中国医科大学口腔医学院中心实验室完成。选择18～22 g SPF级昆明小鼠18只,适应性喂养1周后,随机分为3组,每组6只。组1为接种P.gingivalis W83菌株组,组2为接种P.gingivalis PG0839基因突变菌株组,组3为对照组。在组1、组2的每只小鼠背部皮下2个位点各注射浓度为1×109 CFU/mL的细菌悬液0.1 mL,组3的每只小鼠注射等量无菌PBS缓冲液。在细菌接种后5 d处死各组小鼠,留存肝组织及血清。使用双抗体夹心酶联免疫吸附（ELISA）法检测各组小鼠肝组织和血清中IL-1β与IL-6水平。应用SPSS 13.0统计软件对结果数据进行分析。结果 组2小鼠肝组织和血清中的IL-1β与IL-6表达显著低于组1小鼠（P＜0.05）;与组3小鼠相比,组1和组2小鼠肝组织和血清中IL-1β与IL-6表达均显著增加（ P < 0. 05）。结论 PG0839基因可能参与P.gingivalis引发小鼠全身炎症的过程。     

牙龈卟啉单胞菌对牙髓成纤维细胞胞内感染的研究

目的研究牙龈卟啉单胞菌活菌细胞内感染牙髓成纤维细胞的体外模型。方法将牙龈卟啉单胞菌和牙髓细胞以100∶1比例共同孵育0.5、1.0、2.0 h,倒置显微镜观察牙髓细胞形态。加入双抗和甲硝唑杀死胞外细菌,牙髓细胞用蒸馏水裂解后厌氧培养细胞裂解液,观察活细菌是否进入牙髓细胞胞内。将牙龈卟啉单胞菌和牙髓细胞以多重感染比（MOI）100、50共同孵育1.0 h,采用MTT法检测感染牙龈卟啉单胞菌后牙髓细胞存活率。结果倒置显微镜下显示,被胞内感染的牙髓细胞培养2.0 h未见胞膜破裂,形态完整。采用双抗能彻底杀灭胞外培养基中的细菌而对胞内细菌无影响,共同孵育1.0 h和2.0 h活细菌能进入牙髓细胞。MTT法显示细菌感染后牙髓细胞仍有一定存活率,其存活率分别是MOI 100组74.43%、MOI 50组99.07%。结论成功建立了牙龈卟啉单胞菌对牙髓成纤维细胞胞内感染的模型。     

Direct and indirect effects of Porphyromonas gingivalis lipopolysaccharide on interleukin-6 production by human gingival fibroblasts

We examined the production of interleukin-6 (IL-6) by human gingival fibroblasts (ATCC CRL 1292) stimulated with lipopolysaccharide (LPS) from Porphyromonas gingivalis and Escherichia coli, or supernatant of human peripheral blood adherent cell culture medium incubated in the presence of IL-1 and the same two LPS. Confluent monolayers of gingival fibroblasts were incubated with stimulants for 6 h at 37 degrees C in 5% CO2 and air. After removal of stimulants, the cell cultures were incubated for an additional 2 or 24 h in the same environment. At the end of the culture period, supernatants were collected and assayed for IL-6 activity by stimulatory IgG production with the human B-lymphoblastoid cell line CESS. The direct effect of LPS on IL-6 production by gingival fibroblasts was much weaker than the indirect one via IL-1 production by adherent cells. The stimulating effect of culture supernatants of adherent cells stimulated with LPS on IL-6 production by gingival fibroblasts was as effective as that of recombinant IL-1, when this latter was added at a concentration equivalent to that contained in the culture supernatant of adherent cells. These results suggest that, although gingival fibroblasts may be involved in the pathogenesis of chronic periodontal disease by the production of cytokines, such a role may not result from a direct stimulation by periodontopathic bacteria. The phenomenon is more likely to be mediated indirectly by IL-1 produced by infiltrating inflammatory cells.     

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目的    探讨牙龈卟啉单胞菌（Porphyromonas gingivalis,Pg）对骨细胞凋亡的诱导作用,及其对骨质破坏的影响。方法    2009年8—12月于昆明医学院口腔实验室,选取昆明小鼠60只,随机分为实验组和对照组,每组30只。于实验组小鼠头骨中线两耳之间的部位注射一定浓度的Pg细菌悬液;对照组动物在同样条件下注射等量的0.01 mol／L PBS液。分别于注射后当即及第1、3、5、8、12 天处死,保留整个头颅骨进行固定、脱钙和包埋,原位末端标记（TUNEL）法观察骨细胞的凋亡状况,并计算细胞凋亡率。结果    实验组在注射后第1天,细胞凋亡率较注射前显著增加,第5天达峰值［（35.64% ± 3.69）%］,第8、12 天的细胞凋亡率有所下降;与对照组相比,差异均有统计学意义（P < 0.05）。结论    Pg具有诱导骨细胞凋亡的作用,提示大量骨细胞凋亡可能是牙周炎骨组织破坏产生而重建愈合相对不足的原因之一。     

An acute injection of Porphyromonas gingivalis lipopolysaccharide modulates the OPG/RANKL system and interleukin-6 in an ovariectomized mouse model

Background/aims:  In the present study, we attempted to develop a simulated model to explore the causal effects of periodontal pathogens on skeletal homeostasis in postmenopausal osteoporosis.
Methods:  Fifty-three female adult ICR mice were randomly assigned to an experimental group (ovariectomized) or a control group. A single injection of Porphyromonas gingivalis lipopolysaccharide ( P. gingivalis -LPS, ATCC 33277) or Escherichia coli lipopolysaccharide ( E. coli -LPS) was administered intraperitoneally 4 weeks after an ovariectomy. Concentrations of interleukin-6 (IL-6), osteoprotegerin (OPG), and the receptor activator of nuclear factor-κB ligand (RANKL) in serum were subsequently analyzed using an enzyme-linked immunosorbent assay (ELISA).
Results:  Under stimulation with P. gingivalis -LPS or E. coli -LPS, the concentration of OPG rose in both groups. The serum level of RANKL showed a decreasing trend 24 h after the injection in both groups. After injection of P. gingivalis -LPS in both the experimental and control animals, the OPG : RANKL ratio increased 24 h after the booster (22.26–620.99, P  < 0.05). The serum level of IL-6 in the experimental group significantly increased 1–6 h after administration of E. coli -LPS and 1–3 h after administration of P. gingivalis -LPS ( P  < 0.05).
Conclusions:  A single booster injection of P. gingivalis -LPS induced short-term changes in OPG, RANKL, and IL-6 serum levels in this ovariectomized mouse model.     

Adherence of Porphyromonas gingivalis to gingival epithelial cells: modulation of bacterial protein expression

The protein profiles of Porphyromonas gingivalis (ATCC 33277 and W83) bound to KB gingival epithelial cells were analyzed by SDS-PAGE and immunoblotting. We found that a 51-kDa component was formed in bacteria that adhered to the KB cells, whereas 26- to 29-kDa bands were less intensive, in contrast to the protein profile of free bacteria. P. gingivalis ATCC 33277 incubated with protease-treated KB cells retained the profile of free bacteria. These results demonstrate the specificity of bacterial recognition of eukaryotic membrane components.     

Porphyromonas gingivalis stimulates TACE production by T cells

Introduction: Tumour necrosis factor‐α converting enzyme (TACE), also known as ADAM17, is a membrane‐bound metalloprotease and disintegrin. It is produced by a number of host cells and is known to shed and release cell‐bound cytokines, particularly members of the tumour necrosis factor family. The aim of this study was to investigate the effect of Porphyromonas gingivalis on TACE production by a human T‐cell line, to identify putative virulence factors involved in this process, and to investigate the effect of doxycycline. Methods: P. gingivalis 6‐day culture supernatants were used to challenge Jurkat T cells for 6 h. Secreted and cell‐associated TACE levels were measured by enzyme‐linked immunosorbent assay, whereas messenger RNA expression was investigated by quantitative real‐time polymerase chain reaction. To investigate the involvement of cysteine proteases or proteinaceous components in general, P. gingivalis culture supernatants were treated with the specific chemical inhibitor TLCK or heat‐inactivated, respectively. The effect of doxycycline on the regulation of TACE secretion by P. gingivalis was also investigated. Results: P. gingivalis challenge resulted in a concentration‐dependent enhancement of TACE messenger RNA expression and protein release by Jurkat cells. TLCK treatment or heat treatment of P. gingivalis culture supernatants decreased TACE release to control levels. Doxycycline inhibited TACE secretion dose dependently. Conclusion: The induction of TACE by T cells in response to P. gingivalis may in turn favour the shedding of host cell‐bound cytokines into the local microenvironment, potentially amplifying the inflammatory response. In the present experimental system, P. gingivalis cysteine proteases are involved in TACE release by T cells.     

五倍子水提取物对Pg LPS诱导单核细胞分泌IL-6的抑制作用

目的：研究百倍子水提取物对牙龈卟啉菌(Pg)内毒素(LPS)介导的人单核细胞分泌IL-6水平的影响。方法：采用健康人外周血分离培养的单核细胞以25μg/ml牙龈卟啉菌内毒素作为刺激因子，用放射免疫分析法(RIA)测定细胞培养上清中IL-6的水平，观察5种浓度瓦倍子水提取物对单核细胞分泌炎性细胞因子的影响，结果：五倍子水提取物可显著抑制牙龈卟啉菌内毒素诱导人单核细胞分泌IL-6的水平，其作用在一定范围内呈浓度依赖性。结论：五倍子水提取物能够显著抑制牙龈卟啉菌内毒素诱导人单核细胞分泌IL-6的水平，提示五倍子具有一定的抗炎作用，有助于对牙周病的防治。     

Calprotectin release from human neutrophils is induced by Porphyromonas gingivalis lipopolysaccharide via the CD-14-Toll-like receptor-nuclear factor kappaB pathway

OBJECTIVES: Calprotectin is a cytosolic protein with antibacterial action in leukocytes and its level increases in some inflammatory diseases, including periodontal diseases, rheumatoid arthritis and ulcerative colitis. Recently, we found that the lipopolysaccharide of Porphyromonas gingivalis (P-LPS) induced calprotectin release from human neutrophils. P-LPS, a major virulence factor of periodontal pathogens, is known to induce the production and release of inflammatory cytokines through CD14, Toll-like receptor (TLR) and nuclear factor kappaB (NF-kappaB). In the present study, we investigated whether calprotectin release by P-LPS is induced via the CD14-TLR-NF-kappaB pathway and the cellular mechanism of calprotectin release in human neutrophils. MATERIAL AND METHODS: Human neutrophils were isolated from the peripheral blood of healthy donors and pre-incubated in medium containing antibodies against CD14, TLR2 and TLR4, or several inhibitors of NF-kappaB, microtubules and microfilaments, and then incubated with P-LPS. The calprotectin amount in the culture medium was determined using ELISA, and the nuclear extracts from cells were used for the examination of NF-kappaB binding activity using electrophoretic mobility shift assays. RESULTS: P-LPS increased calprotectin release from neutrophils and its induction was inhibited by anti-CD14 and anti-TLR2 antibodies, but not by two anti-TLR4 antibodies. NF-kappaB inhibitors suppressed P-LPS-induced NF-kappaB binding activity and calprotectin release. The inhibitors of microtubule and microfilament polymerization significantly decreased P-LPS-induced calprotectin release. CONCLUSION: These results suggest that calprotectin release is induced by P-LPS via the CD14-TLR2-NF-kappaB signal pathway in human neutrophils and may be dependent on microtubule and microfilament systems.     

Cytokine production induced by a 67-kDa fimbrial protein from Porphyromonas gingivalis

Fimbriae have been reported to play an important role in the adherence of Porphyromonas gingivalis to oral surfaces and possibly in triggering host responses. P. gingivalis ATCC 33277 has two distinctly different fimbriae expressed on the cell surface. The 67-kDa fimbriae differ in size and antigenicity from the earlier reported FimA, a major 41-kDa fimbrial component of P. gingivalis. Expression of the 67-kDa fimbriae on the cell surface of a fimA mutant was investigated by electron microscopy. The 67-kDa fimbrial protein was purified from the fimA mutant by sonication, precipitation, and chromatography on a DEAE Sepharose CL-6B column. The N-terminal amino acid sequence of the 67-kDa fimbrillin was distinct from that of the 41-kDa fimbrillin. Moreover, we have found that the 67-kDa fimbrial protein from P. gingivalis ATCC 33277 induced IL-1alpha, IL-beta, IL-6 and TNFalpha cytokine expression in mouse peritoneal macrophages. These results suggest that P. gingivalis 67-kDa fimbriae may play a part in the inflammatory response during the development of periodontal diseases.