Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
J Periodontal Res. 2010 Aug;45(4):471-80. doi: 10.1111/j.1600-0765.2009.01260.x. Epub 2010 Mar 9.
Cytolethal distending toxin (CDT) is a genotoxin produced by Aggregatibacter actinomycetemcomitans. In spite of its association with pathogenesis, little is known about the humoral immune response against the CDT. This study aimed to test whether subgingival colonization and humoral response to A. actinomycetemcomitans would lead to a response against CDT.
Sera from periodontally healthy, localized and generalized aggressive periodontitis and chronic periodontitis subjects (n = 80) were assessed for immunoglobulin G titers to A. actinomycetemcomitans serotypes a/b/c and to each CDT subunit (CdtA, CdtB and CdtC) by ELISA. A. actinomycetemcomitans subgingival levels and neutralization of CDT activity were also analyzed.
Sera from 75.0% localized and 81.8% generalized aggressive periodontitis patients reacted to A. actinomycetemcomitans. A response to serotype b was detected in localized (66.7%) and generalized aggressive periodontitis (54.5%). Reactivity to A. actinomycetemcomitans correlated with subgingival colonization (R = 0.75, p < 0.05). There was no correlation between A. actinomycetemcomitans colonization or response to serotypes and the immunoglobulin G response to CDT subunits. Titers of immunoglobulin G to CdtA and CdtB did not differ among groups; however, sera of all generalized aggressive periodontitis patients reacted to CdtC. Neutralization of CDT was not correlated with levels of antibodies to CDT subunits.
Response to CdtA and CdtB did not correlate with the periodontal status of the subject in the context of an A. actinomycetemcomitans infection. However, a response to CdtC was found in sera of generalized but not of localized aggressive periodontitis subjects. Differences in response to CdtC between generalized and localized aggressive periodontitis subjects indicate that CDT could be expressed differently by the infecting strains. Alternatively, the antibody response to CdtC could require the colonization of multiple sites.
细胞致死膨胀毒素（CDT）是伴放线放线杆菌产生的一种遗传毒素。尽管它与发病机制有关，但人们对针对 CDT 的体液免疫反应知之甚少。本研究旨在测试龈下定植和针对伴放线放线杆菌的体液反应是否会导致针对 CDT 的反应。
通过 ELISA 评估牙周健康、局限性和广泛性侵袭性牙周炎和慢性牙周炎受试者（n = 80）的血清针对伴放线放线杆菌血清型 a/b/c 和每个 CDT 亚基（CdtA、CdtB 和 CdtC）的 IgG 滴度。还分析了伴放线放线杆菌龈下水平和 CDT 活性的中和。
75.0%的局限性和 81.8%的广泛性侵袭性牙周炎患者的血清对伴放线放线杆菌有反应。在局限性（66.7%）和广泛性侵袭性牙周炎（54.5%）中检测到对血清型 b 的反应。对伴放线放线杆菌的反应与龈下定植相关（R = 0.75，p < 0.05）。伴放线放线杆菌定植或对血清型的反应与针对 CDT 亚基的免疫球蛋白 G 反应之间没有相关性。CdtA 和 CdtB 的 IgG 滴度在各组之间没有差异；然而，所有广泛性侵袭性牙周炎患者的血清均对 CdtC 有反应。CDT 的中和与针对 CDT 亚基的抗体水平无关。
在伴放线放线杆菌感染的情况下，针对 CdtA 和 CdtB 的反应与受试者的牙周状况无关。然而，在广泛性侵袭性牙周炎患者的血清中发现了针对 CdtC 的反应，但在局限性侵袭性牙周炎患者的血清中没有发现。广泛性和局限性侵袭性牙周炎患者对 CdtC 的反应差异表明，CDT 可能由感染株以不同的方式表达。或者，针对 CdtC 的抗体反应可能需要多个部位的定植。
