Bokor-Bratić M
Klinika za stomatologiju, Medicinski fakultet, Novi Sad.
Med Pregl. 2000 Mar-Apr;53(3-4):164-8.
Whole saliva is a product of secretion of 3 major glands (parotid, submandibular, sublingual) and many minor glands (labial, buccal, palatal). Unstimulated saliva is usually obtained as the patient spits out every 60 sec. or by forward bended head the patient allows saliva to drip off the lower lip into a cylinder. By collection of saliva in the tube the flow rate per unit time can be measured. When volume measurement is not required the saliva can be collected on cotton rolls, gauze or filter paper. For evaluating salivary gland function or when large volumes of saliva are required for analytic purposes, stimulated whole saliva is used. Method of collection is the same as for unstimulated saliva. The usual masticatory stimuli are paraffin wax or a washed rubber band. A standard gustatory stimulus is obtained by 2% citric acid applied directly to the tongue every 15 to 60 sec. Parotid saliva can be collected by aspiration from the duct opening with a micropipette. Parotid saliva is best collected with Lashley's vacuum chamber. Submandibular and sublingual saliva can be collected by cannulation of the duct with micropipette, but in practice this is both uncomfortable for the patients and technically difficult since the duct orifice is mobile and has a strong sphincter. Because of that, alginate and silicone impression material is used for retention of the collecting tube. As alternative and simple technique is to block off secretion from the parotid glands with absorbent swabs and collect mixed submandibular and sublingual saliva by pipette from the floor of the mouth. Saliva from labial and palatal glands can be collected by filter paper disc or disc of other synthetic materials. SALIVARY IMMUNOGLOBULIN A: The most significant characteristics of the salivary immunoglobulin system are quantitative domination of immunoglobulin A, local synthesis and specific structure. Immunofluorescence studies have shown that immunoglobulin A is produced by plasma cells locally in the salivary glands. There is still little convincing evidence for the origin of predominantly immunoglobulin A secreting plasma cells in salivary glands. DETECTION OF IMMUNOGLOBULIN A IN SALIVA: Radial immunodiffusion (RID) was the most applicable method for detecting salivary immunoglobulin A. However, there are more sensitive and automatic methods such as nephelometry and ELISA. A standard level of immunoglobulin in saliva is still in question since the concentration varies in relation to origin of saliva, method of collection and stimulation of secretion (Table 1). PERIODONTAL DISEASE: Studies of the salivary immunoglobulin A in patients with periodontal disease and healthy persons showed that there are differences which can be used in detection of high-risk groups and individuals. If the bacterial adherence to the mucosa is a prerequisite for bacterial evolution in subgingival or any other region of the oral cavity respectively introduction in periodontitis development, than it is to be presumed that the basic function of salivary immunoglobulin A is inhibition of bacterial adherence rather than antigens destruction. Several bacterial species frequently isolated from the oral cavity of patients with periodontitis have been identified as producers of IgA protease. These enzymes cleave serum IgA and secretory IgA equally well. Additionally, most of the IgA proteases studied have cleaved the A1 and A2 subclass. Several studies have demonstrated that cleavage of human IgA occurs in vivo, resulting in generation of intact Fab alpha and (Fc alpha)2 fragment. Moreover, when bacteria are exposed to Fab alpha fragments released from IgA after cleavage by IgA protease, their surface antigens are likely to be occupied by Fab alpha fragments. These Fab alpha fragments left on the bacterial surface may mediate adhesion. Together, these results indicate that IgA proteases, by promoting adherence, contribute the pathogenic potential of bacteria in the oral c
全唾液是由3对大唾液腺（腮腺、颌下腺、舌下腺）以及许多小唾液腺（唇腺、颊腺、腭腺）分泌产生的。通常让患者每隔60秒吐出一次来获取非刺激性唾液，或者让患者头部前倾，使唾液从下唇滴入量筒。通过收集量筒中的唾液，可以测量单位时间的流速。当不需要测量体积时，唾液可以收集在棉卷、纱布或滤纸上。为评估唾液腺功能或出于分析目的需要大量唾液时，则使用刺激性全唾液。采集方法与非刺激性唾液相同。常用的咀嚼刺激物是石蜡或清洗过的橡皮筋。标准味觉刺激是每隔15至60秒将2%的柠檬酸直接涂于舌头上。腮腺唾液可通过用微量移液器从导管开口处抽吸来收集。用拉什利真空室收集腮腺唾液效果最佳。颌下腺和舌下腺唾液可以通过用微量移液器插管导管来收集，但实际上这对患者来说既不舒服，技术上也很困难，因为导管口是活动的且有强大的括约肌。因此，使用藻酸盐和硅橡胶印模材料来固定收集管。另一种简单的技术是用吸水棉签阻断腮腺分泌，然后用移液器从口腔底部收集混合的颌下腺和舌下腺唾液。唇腺和腭腺的唾液可以用滤纸圆盘或其他合成材料圆盘来收集。
唾液免疫球蛋白A：唾液免疫球蛋白系统最显著的特征是免疫球蛋白A在数量上占主导、局部合成以及特定结构。免疫荧光研究表明，免疫球蛋白A是由唾液腺中的浆细胞在局部产生的。关于唾液腺中主要分泌免疫球蛋白A的浆细胞的起源，目前仍缺乏确凿的证据。
唾液中免疫球蛋白A的检测：放射免疫扩散法（RID）是检测唾液免疫球蛋白A最适用的方法。然而，还有更灵敏和自动化的方法，如散射比浊法和酶联免疫吸附测定法。由于唾液免疫球蛋白的浓度因唾液来源、采集方法和分泌刺激方式而异（表1），唾液中免疫球蛋白的标准水平仍存在疑问。
对牙周疾病患者和健康人的唾液免疫球蛋白A的研究表明，两者存在差异，这些差异可用于检测高危人群和个体。如果细菌黏附于黏膜是龈下或口腔其他任何区域细菌发展的前提条件，进而参与牙周炎的发展，那么可以推测唾液免疫球蛋白A的基本功能是抑制细菌黏附，而非破坏抗原。从牙周炎患者口腔中经常分离出的几种细菌已被鉴定为IgA蛋白酶的产生菌。这些酶能同样有效地裂解血清IgA和分泌型IgA。此外，大多数研究的IgA蛋白酶都能裂解A1和A2亚类。多项研究表明，人体内会发生人IgA的裂解，产生完整的Fabα和（Fcα）2片段。此外，当细菌暴露于IgA蛋白酶裂解IgA后释放的Fabα片段时，其表面抗原很可能被Fabα片段占据。留在细菌表面的这些Fabα片段可能介导黏附。综上所述，这些结果表明，IgA蛋白酶通过促进黏附，增加了口腔中细菌的致病潜力。
