Helm R, Cockrell G, Stanley J S, Brenner R J, Burks W, Bannon G A
Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock 72202, USA.
J Allergy Clin Immunol. 1996 Jul;98(1):172-80. doi: 10.1016/s0091-6749(96)70240-3.
Previous studies have established that atopic individuals living in cockroach-infested housing become sensitized to cockroach aeroallergens and produce IgE antibodies to a variety of proteins. We describe the isolation of a complementary DNA clone from an expression library, constructed with messenger RNA from German (Blattella germanica) cockroaches, which encodes a major allergen involved in mediating cockroach hypersensitivity. Approximately 0.2% of the clones from a lambda ZAP XR cDNA library bound IgE from a patient with cockroach sensitivity. A randomly selected subset of these clones revealed that they were either different isolates of the same gene or members of a closely related gene family. One of the largest clones (a 4 kb insert) from this subset, Bla g Bd90K hybridized to a single mRNA of approximately the same size. DNA sequence analysis showed that this gene consisted of seven 576 bp tandem repeats with a short unique region at either end. No significant sequence homologies were found between the cockroach clone and any other gene reported in the GenBank database. Serum from 17 of 22 (77%) patients with cockroach hypersensitivity identified IgE-binding recombinant protein expressed from clone Bla g Bd90K in Escherichia coli XL-Blue cells as determined by sodium dodecylsulfate-polyacrylamide gel electrophoresis/immunoblot analysis. This recombinant protein migrates with a molecular weight (90 kd) apparently similar to one identified in whole body extracts. We have identified and isolated a cDNA that encodes a major cockroach allergen (Bla g Bd90K) present in German cockroaches.
以往的研究已证实，生活在蟑螂肆虐环境中的特应性个体对蟑螂气传变应原产生致敏，并产生针对多种蛋白质的IgE抗体。我们描述了从一个表达文库中分离出一个互补DNA克隆，该文库由德国小蠊（Blattella germanica）的信使核糖核酸构建而成，它编码一种参与介导蟑螂超敏反应的主要变应原。来自λZAP XR cDNA文库的约0.2%的克隆与一名对蟑螂敏感患者的IgE结合。从这些克隆中随机挑选的一个子集显示，它们要么是同一基因的不同分离株，要么是一个密切相关基因家族的成员。该子集中最大的一个克隆（一个4 kb插入片段）Bla g Bd90K与一个大小大致相同的单一信使核糖核酸杂交。DNA序列分析表明，该基因由七个576 bp的串联重复序列组成，两端各有一个短的独特区域。在蟑螂克隆与GenBank数据库中报告的任何其他基因之间未发现明显的序列同源性。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳/免疫印迹分析确定，22例蟑螂超敏患者中有17例（77%）的血清识别出在大肠杆菌XL-Blue细胞中由克隆Bla g Bd90K表达的IgE结合重组蛋白。这种重组蛋白的迁移分子量（90 kd）显然与在全身体外提取物中鉴定出的一种蛋白相似。我们已经鉴定并分离出一个编码德国小蠊中存在的主要蟑螂变应原（Bla g Bd９０K）的cDNA。
