Sahasrabudhe K S, Kimball J R, Morton T H, Weinberg A, Dale B A
Dept. of Oral Medicine, University of Washington, Seattle 98195-7132, USA.
J Dent Res. 2000 Sep;79(9):1669-74. doi: 10.1177/00220345000790090601.
The oral cavity is exposed to a variety of environmental insults. Salivary secretions play a critical role in maintaining oral health via innate host defense mechanisms and secretion of secretory IgA. Human beta-defensins (hBD) are antimicrobial peptides that are a component of the innate immune response; they are expressed in epithelia and are proposed to have a role in mucosal defense. hBD-1 mRNA is constitutively expressed in numerous mucosal tissues, including human gingiva and submandibular and parotid glands. Our objective was to detect the expression and localization of hBD-1 peptide in human salivary glands and in saliva. Minor salivary gland tissue was obtained from biopsies of patients with mucoceles (n = 20). hBD-1 peptide was detected by immunohistochemistry; expression was localized to the ductal cells and not the acinar cells of these glands. The peptide was located apically, toward the lumen in the duct cells. Further evaluation showed stronger hBD-1 expression in ducts with periductal inflammation, as indicated by the immunostaining of serial sections with anti-CD45 specific for B- and T-lymphocytes. Statistical analysis showed a strong correlation of hBD-1 staining and inflammation. Results of immunolocalization suggest that hBD-1 functions to protect salivary glands from retrograde infection, that expression of the peptide is enhanced in inflamed sites, and that post-transcriptional regulatory mechanisms may be involved in hBD-1 peptide expression. Western immunoblot analysis also detected hBD-1 peptide in unstimulated, whole, acidified saliva from normal volunteers. However, hBD-1 peptide associated with salivary mucin resulted in loss of the detection in a dot-immunoblot assay. Association of hBD-1 with salivary mucin may facilitate peptide distribution and adherence to oral surfaces and aid its function within the oral cavity.
口腔暴露于多种环境侵害因素中。唾液分泌通过固有宿主防御机制和分泌性IgA的分泌在维持口腔健康方面发挥关键作用。人β-防御素（hBD）是固有免疫反应的组成部分，为抗菌肽；它们在上皮中表达，并被认为在黏膜防御中发挥作用。hBD-1 mRNA在包括人牙龈、颌下腺和腮腺在内的多种黏膜组织中组成性表达。我们的目的是检测hBD-1肽在人唾液腺和唾液中的表达及定位。从黏液囊肿患者（n = 20）的活检组织中获取小唾液腺组织。通过免疫组织化学检测hBD-1肽；其表达定位于这些腺体的导管细胞而非腺泡细胞。该肽位于顶端，朝向导管细胞的管腔。进一步评估显示，如用针对B淋巴细胞和T淋巴细胞的抗CD45对连续切片进行免疫染色所示，在伴有导管周围炎症的导管中hBD-1表达更强。统计分析显示hBD-1染色与炎症之间存在强相关性。免疫定位结果表明，hBD-1的功能是保护唾液腺免受逆行感染，该肽在炎症部位的表达增强，并且转录后调控机制可能参与hBD-1肽的表达。蛋白质免疫印迹分析也在正常志愿者未刺激的全酸化唾液中检测到hBD-1肽。然而，与唾液黏蛋白结合的hBD-1肽在斑点免疫印迹试验中导致检测失败。hBD-1与唾液黏蛋白的结合可能有助于肽在口腔表面的分布和黏附，并有助于其在口腔内发挥功能。
