Williams J C, Hoover T A, Waag D M, Banerjee-Bhatnagar N, Bolt C R, Scott G H
United States Army Medical Research Institute of Infectious Diseases, Department of Intracellular Pathogens, Fort Detrick, Frederick, Maryland 21701-5011.
Ann N Y Acad Sci. 1990;590:370-80. doi: 10.1111/j.1749-6632.1990.tb42243.x.
The antigenic structure of Coxiella burnetii is being investigated by identifying both external and internal cellular epitopes of the morphologic cell types. Both the phase I lipopolysaccharide (LPSI) and several surface proteins are candidates for the development of subunit multivalent vaccines. The protective efficacy of purified LPSI was demonstrated in A/J mice. The purified LPSI preparations contained residual peptides detected by amino acid analysis. Therefore, the protection afforded by LPSI may be, in part, due to the presence of peptides. The purification of proteins free of LPSI must be accomplished before the protective efficacy of proteins or peptides can be established. We have identified three proteins that are both antigenic and immunogenic, as indicated by either enzyme immunoassay, radioimmunoprecipitation, immunoblot assay, or lymphocyte transformation. A 62-kDa protein antigen encoded by the htpB gene of C. burnetii was analyzed for immunogenicity. The purified protein antigen was immunogenic, as it elicited specific antibodies and performed as recall antigen in lymphocyte stimulation assays. The antigen was not detected on the surface of phase I cells but was highly represented on the surface of phase II cells. Therefore, the protein may not be a good candidate for vaccine development. The diagnostic utility of the 62-kDa protein antigen lies in the fact that convalescent and chronic Q fever sera from human patients reacted with the antigen, whereas acute sera did not. Although the 62-kDa protein is a "common antigen," specific peptide-based diagnostic reagents may be useful in the detection of Q fever disease progression. A major surface protein (P1) of roughly 29.5 kDa was purified from the phase I Nine Mile (clone 7) strain. No LPSI was detected in the P1 preparation by three different LPSI monoclonal antibodies. Monoclonal antibodies prepared against P1 were effective in localizing the protein on the cell surface, in the cell wall, and associated with the peptidoglycan of large cells of C. burnetii. Small, pressure-resistant cells did not contain P1. Mice immunized with two 25-micrograms injections of LPSI produced antibodies against LPSI and phase I whole cells. No antibody was detected against phase II whole cells. Immunization with P1 induced antibody against the LPSI fraction and phase I and phase II whole cells. P1 was more effective than LPSI in reducing the number of infectious C. burnetii in the spleens of challenged mice. The gene encoding another protein (P2) recognized by P1 monoclonal antibodies was cloned and sequenced.(ABSTRACT TRUNCATED AT 400 WORDS)
通过鉴定不同形态细胞类型的细胞表面和内部表位，正在对伯纳特柯克斯体的抗原结构进行研究。I相脂多糖（LPSI）和几种表面蛋白都是亚单位多价疫苗开发的候选对象。纯化的LPSI在A/J小鼠中显示出保护效力。通过氨基酸分析检测到纯化的LPSI制剂中含有残留肽段。因此，LPSI提供的保护作用可能部分归因于肽段的存在。在确定蛋白质或肽段的保护效力之前，必须完成不含LPSI的蛋白质的纯化。我们已经鉴定出三种具有抗原性和免疫原性的蛋白质，这通过酶免疫测定、放射免疫沉淀、免疫印迹测定或淋巴细胞转化得以证实。对由伯纳特柯克斯体htpB基因编码的一种62 kDa蛋白质抗原进行了免疫原性分析。纯化的蛋白质抗原具有免疫原性，因为它能引发特异性抗体，并在淋巴细胞刺激试验中作为回忆抗原发挥作用。该抗原在I相细胞表面未检测到，但在II相细胞表面高度表达。因此，该蛋白质可能不是疫苗开发的理想候选对象。62 kDa蛋白质抗原的诊断效用在于，人类患者的恢复期和慢性Q热血清与该抗原发生反应，而急性期血清则不反应。尽管62 kDa蛋白质是一种“共同抗原”，但基于特定肽段的诊断试剂可能有助于检测Q热疾病的进展。从I相九英里（克隆7）菌株中纯化出一种约29.5 kDa的主要表面蛋白（P1）。三种不同的LPSI单克隆抗体在P1制剂中均未检测到LPSI。针对P1制备的单克隆抗体可有效地将该蛋白质定位在伯纳特柯克斯体大细胞的细胞表面、细胞壁以及与肽聚糖相关的位置。小的耐压细胞不含P1。用两次25微克的LPSI注射免疫小鼠，产生了针对LPSI和I相全细胞的抗体。未检测到针对II相全细胞的抗体。用P1免疫诱导产生了针对LPSI组分以及I相和II相全细胞的抗体。在减少受攻击小鼠脾脏中感染性伯纳特柯克斯体数量方面，P1比LPSI更有效。克隆并测序了编码另一种被P1单克隆抗体识别的蛋白质（P2）的基因。（摘要截短于400字）
