Arruda L K, Vailes L D, Mann B J, Shannon J, Fox J W, Vedvick T S, Hayden M L, Chapman M D
Department of Internal Medicine, University of Virginia Health Sciences Center, Charlottesville 22908, USA.
J Biol Chem. 1995 Aug 18;270(33):19563-8. doi: 10.1074/jbc.270.33.19563.
Inhalation of allergens produced by the German cockroach (Blattella germanica) elicits IgE antibody formation and the development of asthma in genetically predisposed individuals. We compared the allergenic importance of two cockroach (CR) allergens, Bla g 1 and Bla g 2, and determined the complete amino acid sequence of the major 36-kDa allergen, Bla g2. A survey of 106 sera from CR allergic patients showed the prevalence of IgE antibodies to Bla g 1 and Bla g 2 to be 30.2% and 57.6%, respectively. Immediate skin tests on 7 selected patients gave positive reactions using 10(-3) micrograms/ml either allergen, whereas controls showed no response to 10 micrograms/ml. Natural Bla g 2 was purified and the sequence of the NH2 terminus and tryptic peptides, comprising 36% of the molecule, was determined. The cDNA for Bla g 2 was cloned from a B. germanica expression library and encoded a 24-amino acid signal peptide and a 328-amino acid mature protein, which showed the highest degree of identity to mosquito (Aedes aegypti) lysosomal aspartic protease (30.8%), with similar identity to pepsin, cathepsins D and E, renin, and chymosin. Bla g 2 mRNA and protein were detected in B. germanica, but not in Periplaneta americana, the other principal domiciliary CR species in the U.S. High concentrations of Bla g 2 were found in CR digestive organs (esophagus, gut, and proventriculus). The results show that Bla g 2 is a major species-specific allergen of B. germanica and suggest that the allergen functions as a digestive enzyme in the cockroach.
吸入德国小蠊（Blattella germanica）产生的变应原会在具有遗传易感性的个体中引发IgE抗体形成并导致哮喘。我们比较了两种蟑螂（CR）变应原Bla g 1和Bla g 2的变应原重要性，并确定了主要的36 kDa变应原Bla g2的完整氨基酸序列。对106份来自CR过敏患者的血清进行的调查显示，针对Bla g 1和Bla g 2的IgE抗体患病率分别为30.2%和57.6%。对7名选定患者进行的即时皮肤试验显示，使用10（-3）微克/毫升的任何一种变应原均产生阳性反应，而对照组对10微克/毫升无反应。纯化了天然Bla g 2，并确定了占该分子36%的NH2末端和胰蛋白酶肽的序列。从德国小蠊表达文库中克隆了Bla g 2的cDNA，其编码一个24个氨基酸的信号肽和一个328个氨基酸的成熟蛋白，该成熟蛋白与蚊子（埃及伊蚊）溶酶体天冬氨酸蛋白酶的同源性最高（30.8%），与胃蛋白酶、组织蛋白酶D和E、肾素和凝乳酶的同源性相似。在美国，在德国小蠊中检测到Bla g 2 mRNA和蛋白，但在另一种主要的室内CR物种美洲大蠊中未检测到。在CR消化器官（食道、肠道和前胃）中发现了高浓度的Bla g 2。结果表明，Bla g 2是德国小蠊的一种主要的物种特异性变应原，提示该变应原在蟑螂中作为一种消化酶发挥作用。
