A secreted protein that plays a number of roles in modulating the host''s immune response to infection as well as being responsible for bacterial escape into the host cytoplasm. Acts as a strong host (human) T-cell antigen . Inhibits IL-12 p40 (IL12B) and TNF-alpha expression by infected host (mouse) macrophages, reduces the nitric oxide response by about 75% . In mice previously exposed to the bacterium, elicits high level of IFN-gamma production by T-cells upon subsequent challenge by M.tuberculosis, in the first phase of a protective immune response . Higher levels (1.6-3.3 uM) of recombinant protein inhibit IFN-gamma production by host (human) T-cells and also IL-17 and TNF-alpha production but not IL-2; decreases expression of host ATF-2 and JUN transcription factors by affecting T-cell receptors signaling downstream of ZAP70, without cytotoxicity or apoptosis . EsxA inhibits IFN-gamma production in human T-cells by activating p38 MAPK (MAPK14), p38 MAPK is not responsible for IL-17 decrease . Binds host (mouse) Toll-like receptor 2 (TLR2) and decreases host MYD88-dependent signaling; binding to TLR2 activates host kinase AKT and subsequently inhibits downstream activation of NF-kappa-B; the C-terminal 20 residues (76-95) are necessary and sufficient for the TLR2 inhibitory effect . Required for induction of host (human) IL-1B maturation and release by activating the host NLRP3/ASC inflammasome; may also promote access of other tuberculosis proteins to the host cells cytoplasm . Induces IL-8 (CXCL8) expression in host (human) lung epithelial cells . Exogenously applied protein, or protein expressed in host (human and mouse), binds beta-2-microglobulin (B2M) and decreases its export to the cell surface, probably leading to defects in class I antigen presentation by the host cell . Responsible for mitochondrial fragmention, redistribution around the cell nucleus and decreased mitochondrial mass; this effect is not seen until 48 hours post-infection . Able to disrupt artificial planar bilayers in the absence of EsxB (CFP-10) . Native protein binds artificial liposomes in the absence but not presence of EsxB and is able to rigidify and lyse them; the EsxA-EsxB complex dissociates at acidic pH, EsxB might serve as a chaperone to prevent membrane lysis . Recombinant protein induces leakage of phosphocholine liposomes at acidic pH in the absence of ExsB, undergoes conformational change, becoming more alpha-helical at acidic pH . The study using recombinant protein did not find dissociation of EsxA-EsxB complex at acidic pH . Involved in translocation of bacteria from the host (human) phagolysosome to the host cytoplasm . Translocation into host cytoplasm is visible 3 days post-infection using cultured human cells and precedes host cell death . Recombinant protein induces apoptosis in host (human) differentiated cell lines, which is cell-line dependent; bacteria missing the ESX-1 locus do not induce apoptosis . Host (human) cells treated with EsxA become permeable to extracellular dye . EsxA and EsxA-EsxB are cytotoxic to pneumocytes . ESX-1 secretion system-induced host (mouse) cell apoptosis, which is probably responsible for infection of new host cells, might be due to EsxA . EsxA induces necrosis in aged neutrophils . May help regulate assembly and function of the type VII secretion system (T7SS) (By similarity). EsxA disassembles pre-formed EccC-EsxB multimers, possibly by making EccC-EsxA-EsxB trimers instead of EccC-EsxB-EsxB-EccC tetramers (By similarity). .; May be critical in pro-bacteria versus pro-host interactions; ESX-1 mediates DNA mediated export (maybe via EsxA). The DNA interacts with host (human) cGAS, leading to cGAMP production and activation of the host STING-TBK-1-IRF-3 signaling pathway that leads to IFN-beta which is thought to be ''pro-bacteria''. Mycobacterial dsDNA also interacts with AIM2-NLRP3-ASC to activate an inflammasome, leading to the ''pro-host'' IL-1-beta . .

p9wnk7

6 kDa early secretory antigenic target (ESAT-6),esxA esaT6 Rv3875 MTV027.10,6 kDa early secretory antigenic target, ESAT-6, esxA, esaT6, Rv3875, MTV027.10

Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)

ELISA

ELISA 1:5000-1:20000

10kD

Human

Monoclonal

SA419

IgG1

Protein A/G purified from cell culture supernatant.

>95% as determined by SDS-PAGE.

0.01M PBS, pH 7.4.

0.25 mg/ml

Use a manual defrost freezer and avoid repeated freeze-thaw cycles. Store at 4℃ short term (1-2 weeks). Store at -20℃ 12 months.