Weinberg A, Krisanaprakornkit S, Dale B A
Department of Periodontics, Case Western Reserve University, Cleveland, Ohio 44106-4905, USA.
Crit Rev Oral Biol Med. 1998;9(4):399-414. doi: 10.1177/10454411980090040201.
Epithelial tissues provide the first line of defense between an organism and the environment. Disruption of this barrier leads to bacterial invasion and subsequent inflammation. This is precisely the situation existing in the human oral cavity, where tissues are constantly exposed to a variety of microbial challenges that can lead to bacterially induced periodontal diseases, and to infections of the oral mucosa by bacteria, fungi, and viruses. With the recent discoveries of host-derived peptide antibiotics in mammalian mucosal epithelium, a new line of investigation is emerging to test the hypothesis that one class of these peptides, called "beta-defensins", functions to protect the host against microbial pathogenesis at these critical, confrontational sites. In that light, impairment of beta-defensin activity has recently been implicated in chronic bacterial infections in cystic fibrosis patients. The first direct evidence of expression of defensin peptides in the oral mucosa was the identification of a novel epithelial beta-defensin in mammalian tongue. It was shown to be upregulated in inflammation, suggesting that it participates in host defense. It is theorized that epithelial cell-derived antimicrobial peptides function to keep the natural flora of micro-organisms in a steady state in different niches such as the skin, the intestines, the airway, the endocervix, and the mouth. There is now evidence indicating that normal gingival epithelial cells and tissues express two beta-defensins, hBD-1 and the newly described hBD-2. In addition, a cathelin-class antimicrobial peptide, designated LL-37 and found in human neutrophils, is also expressed in skin and gingiva. It is highly likely that these and/or other epithelial antimicrobial peptides play an important role in determining the outcome of the host-pathogen interaction at the oral mucosal barrier, and that they may have important future applications in antibiotic treatment.
上皮组织是生物体与外界环境之间的第一道防线。这一屏障的破坏会导致细菌入侵并引发炎症。人类口腔正是这种情况，口腔组织持续面临各种微生物挑战，这些挑战可能导致细菌引发的牙周疾病，以及细菌、真菌和病毒对口腔黏膜的感染。随着近期在哺乳动物黏膜上皮中发现宿主源性肽抗生素，一项新的研究方向正在兴起，以验证这样一个假说：其中一类名为“β-防御素”的肽在这些关键的对抗部位发挥作用，保护宿主抵御微生物致病作用。鉴于此，β-防御素活性受损最近被认为与囊性纤维化患者的慢性细菌感染有关。口腔黏膜中防御素肽表达的首个直接证据是在哺乳动物舌中鉴定出一种新型上皮β-防御素。研究表明它在炎症中上调，提示其参与宿主防御。理论上，上皮细胞衍生的抗菌肽作用是使微生物的自然菌群在皮肤、肠道、气道、子宫颈和口腔等不同微环境中保持稳定状态。现在有证据表明，正常牙龈上皮细胞和组织表达两种β-防御素，即hBD-1和新描述的hBD-2。此外，一种在人类中性粒细胞中发现的、名为LL-37的cathelin类抗菌肽也在皮肤和牙龈中表达。极有可能的是，这些和/或其他上皮抗菌肽在决定宿主-病原体在口腔黏膜屏障处相互作用的结果方面发挥重要作用，并且它们在抗生素治疗中可能具有重要的未来应用价值。
