Bannantine John P, Stabel Judith R
National Animal Disease Center, ARS-USDA, Ames, IA 50010, USA.
J Med Microbiol. 2001 Sep;50(9):795-804. doi: 10.1099/0022-1317-50-9-795.
The investigation of environmentally regulated proteins has led to a better understanding of host-pathogen interactions and identified novel vaccine candidate antigens for several bacterial pathogens. In an effort to identify such proteins in Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis), a genomic expression library was differentially screened with sera from rabbits that had been immunised with live M. paratuberculosis (alpha-live) as well as sera from rabbits immunised with heat-killed M. paratuberculosis (alpha-killed). These experiments identified seven recombinant plaques that were uniquely recognised by the alpha-live sera. Sequence data showed that five of these clones overlapped with each other and contained a common open-reading frame encoding a 25-kDa protein, termed Csp1. The 25-kDa antigen shows weak similarity to a secreted Corynebacterium glutamicum protein. The remaining two clones overlapped with each other and contained two partial open-reading frames, both encoding proteins with strong homology to polyketide synthase from various species of mycobacteria. Antisera were produced against a peptide of the polyketide synthase gene product designated Pks7. Csp1-specific antibodies were affinity purified from the alpha-live sera. These purified antibodies demonstrated that Csp1 was present within infected macrophages. Collectively, these data identify novel M. paratuberculosis antigens that may be important in pathogenesis.
对环境调控蛋白的研究有助于更好地理解宿主与病原体之间的相互作用，并为几种细菌病原体鉴定出新型疫苗候选抗原。为了在副结核分枝杆菌中鉴定此类蛋白，用活副结核分枝杆菌免疫的兔子血清（α-活血清）以及用热灭活副结核分枝杆菌免疫的兔子血清（α-灭活血清）对基因组表达文库进行了差异筛选。这些实验鉴定出了7个重组噬菌斑，它们仅被α-活血清识别。序列数据显示，其中5个克隆相互重叠，包含一个共同的开放阅读框，编码一种25 kDa的蛋白，称为Csp1。该25 kDa抗原与谷氨酸棒杆菌的一种分泌蛋白有微弱的相似性。其余两个克隆相互重叠，包含两个部分开放阅读框，均编码与各种分枝杆菌的聚酮合酶具有高度同源性的蛋白。针对聚酮合酶基因产物Pks7的一个肽段制备了抗血清。从α-活血清中亲和纯化出Csp1特异性抗体。这些纯化抗体表明Csp1存在于受感染的巨噬细胞内。总体而言，这些数据鉴定出了可能在发病机制中起重要作用的新型副结核分枝杆菌抗原。
