大肠杆菌志贺样毒素Ⅱ型突变体（O139菌型）抗体

大肠杆菌志贺样毒素Ⅱ型突变体（O139菌型）抗体

产品编号        LM0882R    

英文名称    Shiga-like toxin IIe variant subunit A    

中文名称    大肠杆菌志贺样毒素Ⅱ型突变体（O139菌型）抗体    

别    名    shiga-like toxin II variant chain A precursor.      

研究领域    细菌及病毒      

抗体来源    Rabbit    

克隆类型    Polyclonal    

交叉反应    Escherichia Coli,     

产品应用    WB=1:500-2000 ELISA=1:500-1000 IHC-P=1:400-800 IHC-F=1:400-800 IF=1:100-500 （石蜡切片需做抗原修复） 
not yet tested in other applications.
optimal dilutions/concentrations should be determined by the end user.    

分 子 量    36kDa    

性    状    Lyophilized or Liquid    

浓    度    1mg/ml    

免 疫 原    KLH conjugated synthetic peptide derived from Escherichia coli Shiga-like toxin IIe variant subunit A:241-319/319     

亚    型    IgG    

纯化方法    affinity purified by Protein A    

储 存 液    0.01M TBS(pH7.4) with 1% BSA, 0.03% Proclin300 and 50% Glycerol.    

保存条件    Store at -20 °C for one year. Avoid repeated freeze/thaw cycles. The lyophilized antibody is stable at room temperature for at least one month and for greater than a year when kept at -20°C. When reconstituted in sterile pH 7.4 0.01M PBS or diluent of antibody the antibody is stable for at least two weeks at 2-4 °C.    

PubMed    PubMed    

产品介绍    background:
Shiga-like toxin type II (SLT-II) and Shiga-like toxin type II variant (SLT-IIv) are cytotoxins produced by certain strains of Escherichia coli. Nucleotide sequence analyses had revealed that the structural genes for the A subunit and B subunit of SLT-II or SLT-IIv are arranged in an operon. Primer extension and S1 nuclease protection analyses identified a promoter for the slt-II operon 118 bases upstream of the slt-IIA gene. The slt-IIv promoter was demonstrated to be identical to the slt-II promoter. The slt-II and slt-IIv promoters differed significantly from the previously characterized Shiga toxin (stx) and Shiga-like toxin type 1 (slt-I) promoters. The transcriptional efficiencies of the stx and slt-II promoters were compared in fusions to the chloramphenicol acetyltransferase gene, and constitutive expression of the slt-II promoter was found to be equivalent to derepressed expression of the stx promoter. In contrast to the stx and slt-I promoters, the slt-II and slt-IIv promoters did not contain sequences for binding of the Fur repressor protein, and SLT-II production was not determined by iron levels in the media in various E. coli strains with wild-type or mutant ferric uptake regulation (fur) alleles. Northern (RNA) blot analysis demonstrated a single mRNA transcript for the slt-II operon, and further analysis of the slt-II operon by primer extension did not reveal an independent promoter for the B subunit gene. A putative rho-independent transcription terminator was identified 274 bases downstream of slt-IIB. These data indicated that the slt-II and slt-IIv operons differ from the stx/slt-I operon in regulation of their transcription by iron. Whether these regulatory differences enable the type I and type II groups of Shiga-like toxins to perform different roles in the pathogenesis of infectious diseases remains to be established.    

水肿病大肠杆菌志贺样毒素Ⅱ型体，属人、猪、羊、马等哺乳动物共患毒素Ⅱ型体。

抗原抗体结合特点

 1）特异性：抗原分子只能与由它刺激所产生的抗体结合而起反应的专一性能；

 2）可逆性：是指Ag与相应Ab结合成IC后，在一定条件下可解离为游离抗原与抗体。

 3）阶段性：

 一阶段：特异性结合阶段 （①反应速度快，几秒钟或几分钟即可完成 ②不出现肉眼可见反应）；

 第二阶段：可见阶段（表现为凝集、沉淀、补体结合等反应 ①反应进行慢，需要几分钟、几十分钟或更长②受电解质、温度、酸碱度等多种因素影响）。

4）比例性：（最适比或等价点）是指抗原与抗体发生可见反应需遵循一定的量比关系，只有当二者浓度比例适当时，才出现可见反应。

抗原抗体反应影响因素：

（一）反应物自身的因素

5） 抗体：不同来源的抗体,反应性各有差异,抗体的浓度、特异性和亲和力都影响抗体抗原反应,为提高试验的可靠性,应选择高特异性、高亲和力的抗体作诊断试剂.等价带的宽窄也影响抗原抗体复合物的形成,单克隆抗体不适用于沉淀反应.

6）  抗原：抗原的理化性状、分子量、抗原决定簇的种类及数目均可影响反应结果.颗粒性抗原出现凝集反应,可溶性抗原出现沉淀反应,单价抗原与相应抗体结合不出现沉淀现象.

（二）反应环境条件

7） 酸碱度：抗原抗体反应必须在合适的pH环境中进行.蛋白质具有两性电离性质,因此每种蛋白质都有固定的等电点.抗原抗体反应一般在pH6～9进行,有补体参与的反应pH为7.7.4,pH过高或过低都将影响抗原与抗体反应.

8）  温度：在一定范围内,温度升高可加速分子运动,抗原与抗体碰撞机会增多,使反应加速.一般为15℃～40℃,常用的抗原抗体反应温度为37℃,温度如高于56℃,可导致已结合的抗原抗体再解离,甚至变性或破坏.每种试验都有其独特的最适反应温度要求.此外,适当振荡也可促进抗原抗体分子的接触,加速反应.

9）  电解质：抗原与抗体发生特异性结合后,虽由亲水胶体变为疏水胶体,若溶液中无电解质参加,仍不出现可见反应.为了促成沉淀物或凝集物的形成,常用0.85%NaCl或各种缓冲液作为抗原及抗体的稀释液.