Product Specifications:
Item# 105-10: Recombinant M Tuberculosis ESAT-6 Antigen (E.coli)
Concentration: 2mg/vial
Mass/vial: 1mg
Volume/vial: 500ul
Diluent: 50mM NaPO4, pH 7.0, 0.1M NaCl , 0.05% Sod. Sarcosyl >98%
Purity: >98%
Stabilizer: None
Preservative: None
Storage: -75°C
Physical State: Liquid, sterile filled
Stability: 2 year at -75°C
Applications: ELISA, Western ELISA, TB, Diagnostics.
Description: M Tuberculosis ESAT-6 Antigen produced in the E. coli expression system.
Purification: Purified by ion affinity and UF concentration solvent extraction to >98% purity as determined by SDS-PAGE.
Molecular Weight: 13kD
Specificity: This ESAT-6 protein reacts with human TB serum in ELISA and Western ELISA.
Biological Activity: Not determined
Application and Instructions for use:
Recommended concentrations for use are approximate values. A dose dependent response assay should be performed to determine the optimal concentration for use in specific applications.
ELISA and Western ELISA require 10-100ng protein depending on the nature and affinity of the detection reagent. Human serum polyclonal antibodies yield titers of 1:1000 or greater at 100ng of immobilized protein under standard ELISA conditions.
Region of difference 1 to 3 gene
Glossary
Gene and Gene Products
Structural Proteins: Structural proteins – the products of gag, pol and env genes, which are essential components of the retroviral particle.
Regulatory Proteins: Regulatory proteins – tat and rev proteins of HIV/SIV and tax and rex proteins of HTLVs; essential for viral expression in infected cells.
Accessory Proteins: Accessory proteins – additional (non-regulatory) virion – and non virion-associated proteins produced by HIV/SIV retroviruses: vif, vpr, vpu, vpx, and nef. Although, the accessory proteins are not necessary for viral propagation in tissue culture, they have been conserved in the different isolates; this conservation and experimental observations suggest that their role in vivo is very important.
gag
gag – group-sepecifc antigens or capsid proteins; the precursor is the p55 myristoylated protein, which is processed to p17 (Matrix) p24 (Capsid) and p7 (NucleoCapsid) proteins by the viral protease. Other small proteins are generated from the gag polyprotein.
pol
pol – (p66) generates the viral enzymes protease (p11), reverse transcriptase (p51), endonuclease and integrase (p32) after the processing of a gag-pol precursor polyprotein by the viral protease; gag-pol precursor is produced by ribosome frameshifting.
env
env – viral glycoproteins produced as a precursor (gp160) and processed to the external glycoprotein (gp120) and the transmembrane glycoprotein (gp41). The mature proteins are held together by noncovalent interactions; as a result substantial amount of gp120 is released extracellularly. The external glycoprotein (gp120) contains the binding site for the CD4 receptor.
tat
tat – transactivator of HIV gene expression; one of the two necessary viral regulatory factors (tat and rev) for HIV gene expression. Two forms are known, tat-1 exon (minor form) of 72 amino acids, and tat-2 exon (major form) of 86 amino acids. The electrophoretic mobility of these two forms in SDS gels is anomalous; they are approximately 16 kD and 14 kD in weight. Low levels of both proteins are found in persistently infected cells. tat is localized primarily in the nucleolus/nucleus; it acts by binding to the TAR RNA element and activating transcription from the LTR promoter. Post-transcriptional effects of tat have been postulated.
rev
rev – the second necessary regulatory factor for HIV expression. A 19 kD phosphoprotein localized primarily in the nucleolus/nucleus, rev acts by binding to RRE and promoting the nuclear export, stabilization and utilization of the viral mRNAs containing RRE.
vif
vif – viral infectivity factor, typically 23 kD; required for the efficient transmission of cell-free virus in tissue culture. In the absence of vif, the produced viral particles are defective, while the cell-to-cell transmission of virus is not affected significantly. It has been reported that the cellular localization is in the Golgi (vif is not found in the virion).
nef
nef – approximately 27 kD non-virion protein found in the cytoplasm of infected cells. Potentially myristoylated and associated with the inner plasma membrane. One of the first HIV proteins to be produced in the infected cells, it is the most immunogenic of the accessory proteins and may be used in the future for diagnosis and staging of the disease. NEF is dispensable and probably suffers counter-selection during ex vivo viral propagation in vivo. Recent evidence suggests that SIV nef is required for viral propagation in vivo.
vpr
vpr – virion-associated protein of unknown function found in HIV-1, HIV-2, SIVmac, and SIVmnd; typically 15 kD. May be homologous to vpx. Also called “rap” for rapid.
vpu
vpu – protein that promotes extracellular release of viral particles. Found only in HIV-1. Integral membrane phosphoprotein of 16kd; similar to M2 protein of influenza virus. It may be involved in env maturation. It is not found in the virion.
vpx
vpx – virion protein of 12 kD found only in HIV-2 infection. (vpx may have some homology with vpr).
Articles related to ESAT-6
The ESAT-6 Protein of Mycobacterium tuberculosis Interacts with Beta-2-Microglobulin (β2M) Affecting Antigen Presentation Function of Macrophage
ESAT-6, an abundantly secreted protein of Mycobacterium tuberculosis (M. tuberculosis) is an important virulence factor, inactivation of which leads to reduced virulence of M. tuberculosis. ESAT-6 alone, or in complex with its chaperone CFP-10 (ESAT-6:CFP-10), is known to modulate host immune responses; however, the detailed mechanisms are not well understood. The structure of ESAT-6 or ESAT-6:CFP-10 complex does not suggest presence of enzymatic or DNA-binding activities. Therefore, we hypothesized that the crucial role played by ESAT-6 in the virulence of mycobacteria could be due to its interaction with some host cellular factors. Using a yeast two-hybrid screening, we identified that ESAT-6 interacts with the host protein beta-2-microglobulin (β2M), which was further confirmed by other assays, like GST pull down, co-immunoprecipitation and surface plasmon resonance. The C-terminal six amino acid residues (90–95) of ESAT-6 were found to be essential for this interaction. ESAT-6, in complex with CFP-10, also interacts with β2M. We found that ESAT-6/ESAT-6:CFP-10 can enter into the endoplasmic reticulum where it sequesters β2M to inhibit cell surface expression of MHC-I-β2M complexes, resulting in downregulation of class I-mediated antigen presentation. Interestingly, the ESAT-6:β2M complex could be detected in pleural biopsies of individuals suffering from pleural tuberculosis. Our data highlight a novel mechanism by which M. tuberculosis may undermine the host adaptive immune responses to establish a successful infection. Identification of such novel interactions may help us in designing small molecule inhibitors as well as effective vaccine design against tuberculosis.
M. tuberculosis is a dangerous and highly successful pathogen that has evolved several mechanisms to manipulate the host immune regulatory network. Proteins secreted by M. tuberculosis play important roles in virulence. One such protein is ESAT-6, which is secreted along with its chaperone CFP-10. Despite a host of studies highlighting modulation of immune responses by ESAT-6, there have not been many that identified host proteins interacting with ESAT-6. We have now found that the host protein β2M interacts very specifically with ESAT-6 at its C-terminal region. The soluble ESAT-6:CFP-10 complex was found to be trafficked into the endoplasmic reticulum, and treatment with recombinant ESAT-6:CFP-10 or the over-expression of ESAT-6 reduced cell surface expression of β2M and molecules which remain associated with it like HLA-I. Recombinant ESAT-6:CFP-10 was also found to reduce classical and cross presentation of peptide antigens by MHC-I molecules. In summary, our data indicate that interaction between ESAT-6 and β2M can reduce the levels of available free β2M that associate with HLA/MHC-I molecules. This could be an interesting mechanism by which M. tuberculosis inhibits classical and cross presentation of peptide antigens in order to prevent or delay the onset of anti-mycobacterial adaptive immune responses.
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所以一个细菌或病毒可以有很多的抗原。
荚膜是某些细菌在细胞壁外包围的一层粘液性物质，一般由糖和多肽组成，是细菌的一种特殊结构。
作用：
①抗吞噬作用：荚膜因其亲水性及其空间占位、屏障作用，可有效抵抗寄主吞噬细胞的吞噬作用。
②黏附作用：荚膜多糖可使细菌彼此间粘连，也可黏附于组织细胞或无生命物体表面，是引起感染的重要因素，具有荚膜的S-型肺炎链球菌毒力强，有助于肺炎链球菌侵染人体；废水生物处理中的细菌荚膜有生物吸附作用，将废水中的有机物、无机物及胶体吸附在细菌体表面上。
③抗有害物质的损伤作用：处于细菌细胞最外层，荚膜犹如盔甲可有效保护菌体免受或少受多种杀菌、抑菌物质的损伤，如溶菌酶、补体等。
④抗干燥作用：荚膜多糖为高度水合分子，含水量在95%以上，可帮助细菌抵抗干燥对生存的威胁。
⑤当缺乏营养时，荚膜可被利用作碳源和能源，有的荚膜还可作氮源。
颗粒型抗原,除了有细菌、红细胞、螺旋体等天然颗粒型抗原,还有吸附有可溶性抗原的非免疫相关颗粒.
颗粒性抗原光镜下可见，比如细菌性抗原、红细胞抗原等；而可溶性抗原在光镜下不可见，如组织浸出液、细菌毒素、蛋白质分子等。
它们不等同于完全抗原和不完全抗原。完全抗原具有免疫原性和抗原性，而不完全抗原只具有抗原性。完全抗原可以是颗粒性抗原，亦可是可溶性抗原，而不完全抗原一般只能是可溶性抗原，不会是颗粒性抗原。
若已进入细胞内。则先由巨噬细胞吞噬降解。并形成抗原-MHC复合体传送到表面。被辅助性T淋巴细胞识别和效应T淋巴细胞识别后。效应T淋巴细胞被激活。分解靶细胞。然后再由效应B细胞分泌的抗体进一步消灭病毒。
还有不清楚的么？
