Fine D H, Furgang D, Beydouin F
Department of Oral Pathology and Biology, University of Medicine and Dentistry of New Jersey, New Jersey Dental School, Newark 07103, USA.
J Periodontol. 2002 Jun;73(6):624-30. doi: 10.1902/jop.2002.73.6.624.
Actinobacillus actinomycetemcomitans (Aa) is associated with localized aggressive periodontal disease in juveniles (LAgP). Lactoferrin (LF) is an iron-binding salivary protein that has been shown to kill Aa in its iron-free form (apo) and reduce binding to host cells in its iron-saturated form (halo). However, recent in vitro studies show that LF does not kill clinical isolates of Aa, and LF with reduced levels of bound iron does not interfere with its attachment. These findings suggest that colonization of Aa may occur more readily in an environment containing LF with low iron levels. The purpose of this study was to examine the relationship of LF iron levels in saliva of LAgP patients as compared to their age-, gender-, and race-matched controls.
Whole and parotid saliva was collected from LAgP patients and matched controls. Micrograms of LF/mg of protein as well as nanograms of iron/micrograms of LF were determined. Iron binding was determined in parotid saliva by addition of nonlabeled and 59Fe labeled iron.
LAgP patients' whole saliva had higher LF levels than controls, but their LF contained less iron (P < or =0.005). No iron was found in LF from parotid saliva in either group. When iron was added to parotid saliva, the LAgP saliva bound 20 to 30 times less iron than controls (P< or =0.001). Finally, LF was identified as the major iron-binding protein in parotid saliva by 59Fe autoradiography and Western blotting.
This study shows that the level of bound iron in LF is significantly reduced in LAgP patients compared to controls. These data suggest that LF from LAgP patients has a reduced capacity to bind iron and that LF iron levels may play an important role in Aa-induced LAgP.
伴放线放线杆菌（Aa）与青少年局限性侵袭性牙周炎（LAgP）相关。乳铁蛋白（LF）是一种结合铁的唾液蛋白，已证明其无铁形式（脱铁乳铁蛋白）可杀死Aa，而其铁饱和形式（乳铁传递蛋白）可减少与宿主细胞的结合。然而，最近的体外研究表明，LF不能杀死Aa的临床分离株，且结合铁水平降低的LF不会干扰其附着。这些发现表明，在含铁量低的LF环境中，Aa的定植可能更容易发生。本研究的目的是检查LAgP患者唾液中LF铁水平与其年龄、性别和种族匹配的对照组之间的关系。
从LAgP患者和匹配的对照组中收集全唾液和腮腺唾液。测定每毫克蛋白质中LF的微克数以及每微克LF中铁的纳克数。通过添加未标记和59Fe标记的铁来测定腮腺唾液中的铁结合情况。
LAgP患者的全唾液中LF水平高于对照组，但其LF含铁量较少（P≤0.005）。两组腮腺唾液中的LF均未检测到铁。当向腮腺唾液中添加铁时，LAgP唾液结合的铁比对照组少20至30倍（P≤0.001）。最后，通过59Fe放射自显影和蛋白质印迹法确定LF是腮腺唾液中的主要铁结合蛋白。
本研究表明，与对照组相比，LAgP患者LF中的结合铁水平显著降低。这些数据表明，LAgP患者的LF结合铁的能力降低，且LF铁水平可能在Aa诱导的LAgP中起重要作用。
