INDUCTION OF PNEUMOCOCCAL CARRIAGE IN VOLUNTEERS

感染人类的肺炎球菌(PN)的宿主是人类 呼吸道粘膜，尤指鼻咽部。跟随 在粘膜上的沉积、Pn的生长和寄主防御通常达到 允许生物体无症状携带数周的平衡或 月份。这种平衡可能会被病毒感染等事件打破 促进细菌生长，导致明显的PN感染和/或增强 传播给其他人。多种宿主防御机制在人类免疫系统中的作用 对PN运输的控制没有明确的定义。这样做的目的是 本研究是在健康青年中建立PN载体， 对其进行评估应有助于制定控制措施。 正常人经常携带的两个PN血清型(6和23)，以及 具有低侵袭性风险的健康青年受试者 将采用肺炎链球菌病。初步研究将利用 对所用血清型有血清抗体的受试者。四 受试者将在每个鼻孔内接种0.1毫升疫苗，总剂量 10[1]个CFU。每隔2周以上，后续小组将收到 剂量连续增加10倍，最高可达10[5]CFU，其目标是 确定导致50%的受试者定居的剂量(HCD[50]) 已在具有预先存在的对象中无事故地建立 抗体或10[5]接种失败，将开始研究 缺乏血清抗该血清型抗体的受试者的最低剂量。

The reservoir for pneumococci (Pn) that infect humans is human respiratory mucosa, especially in the nasopharynx. Following deposition on the mucosa, Pn growth and host defenses often reach a balance allowing asymptomatic carriage of the organism for weeks or months. This balance can be upset by events like a virus infection that facilitates bacterial growth causing overt Pn infection and/or enhancing transmission to others. Roles of various host defense mechanisms in controlling Pn carriage are not clearly defined. The purpose of this study is establishement of Pn carriage in healthy young adults, evaluations of which should facilitate development of control measures. Two Pn serotypes (6 and 23) frequently carried by normal persons, and healthy young adult subjects that are at low risk for invasive pneumococcal disease will be employed. Initial studies wil utilize subjects possessing serum antibody to the serotype used. Four subjects will receive 0.1 ml inocula into each nostril with a total dose of 10[1]CFU. At intervals of 2+ weeks, subsequent groups will receive sequential 10-fold increments in dose up to 10[5]CFU, the aim being to establish a dose that causes colonization of 50% of subjects (HCD[50]) has been established without incident in subjects with pre-existing antibody or the 10[5] inoculum has failed, studies will be begun with the lowest dose in subjects lacking serum antibody to the serotype.