
Cataloguenumber
CYT-213
Synonyms
Bcelldifferentiationfactor,BCDF,BSF-2,HPGF,HSF,MGI-2,B-cellstimulatoryfactor2,Hybridomagrowthfactor,CTLdifferentiationfactor,CDF,IL-6,HGF.
Introduction
Description
Source
PhysicalAppearance
Formulation
Solubility
StABIlity
Purity
Aminoacidsequence
BiologicalActivity
Proteincontent
Usage
SafetyDataSheet
SDS
References
Background
IL-6isproducedbymanydifferentcelltypes.Themainsourcesinvivoarestimulatedmonocytes,fibroblasts,andendothelialcells.Macrophages,T-cellsandB-lymphocytes,granulocytes,smoothmusclecells,eosinophils,chondrocytes,osteoblasts,mastcells,glialcells,andkeratinocytesalsoproduceIL6afterstimulation.GlioblastomacellsconstitutivelyproduceIL6andthefactorcanbedetectedalsointhecerebrospinalfluid.HumanmilkalsocontainsIL6(see:MGF,milkgrowthfactor).
CardiacmyxomasandcervicalandbladdercarcinomassecretelargeamountsofIL6intotheconditionedmedium.VeryhighlevelsofIL6arealsodetectedinthesynovialfluidofpatientswithrheumatoidarthritisbutnotwithosteoarthritis.
PhysiologicalstimuliforthesynthesisofIL6areIL1,bacterialendotoxins,TNF,PDGF,andOncostatinM.InfibroblaststhesynthesisofIL6isstimulatedbyIFN-beta,TNF-alpha,PDGF,andviralinfections.InthymicstromalcellsthesynthesisofIL6canbeinducedbyNGF.IL6canalsostimulateorinhibitsitsownsynthesis,dependinguponthecelltype.FortheconstitutiveproductionofIL6seealso:IAP(intracisternalAparticles).Inepithelial,endothelial,andfibroblasticcellssecretionofIL6isinducedbyIL17.
IL6isproducedalsointheanteriorlobeofthepituitaryandcanbeinducedbybacterialendotoxinsandallsubstanceselevatingintracellularlevelsofcAMP(prostaglandinE2,forskolin,choleratoxin).VIP(vasoactiveintestinalpeptide)alsostimulatesthesynthesisofIL6intheanteriorlobeofthepituitarywhileGHreleasinghormoneisinactive.MacrolideantibioticsspiramycinstimulatethesynthesisofIL6inhumanmonocytesfollowingcellactivationbybacteriallipopolysaccharidesbutnotthesynthesisofIL1orTNF-alpha.
GlucocorticoidsinhibitthesynthesisofIL6andIL4orTGF-betareduceitssynthesis.ThesynthesisofIL6byhumanalveolarmacrophagesisinhibitedbyIL4.
InserumIL6iscomplexedwithAlpha-2-Macroglobulin(Alpha2M)whichprotectsIL6fromcleavagebyproteasesandpossIBLyfunctionsasatransportprotein.
ThereleaseofIL6fromisolatedratmacrophagesincultureisstimulatedbyHistogranin.
IL6isaproteinof185aminoacidsglycosylatedatpositions73and172.Itissynthesizedasaprecursorproteinof212aminoacids.MonocytesexpressatleastfivedifferentmolecularformsofIL6withmolecularmassesof21.5-28kDa.Theymainlydifferbypost-translationalalterationssuchasglycosylationandphosphorylation.
IL6isolatedfromvariouscelltypesshowssomemicroheterogeneityinitsN-terminus.A42-45kDaformhasbeenobservedinplasmathatisprobablycomplexedwithacarrierproteinAlpha-2-Macroglobulin(Alpha2M)MurineandhumanIL6show65%sequencehomologyattheDNAleveland42%homologyattheproteinlevel.ForatruncatedformofIL6withantagoNISTactivitiessee:tIL6.IL6isamemberofafamilyofcytokines,whichalsoincludesLIF,CNTF,OncostatinM,IL11,andCT-1.AllknownmembersoftheIL6cytokinefamilyinducehepaticexpressionofacutephaseproteins.
IL6-Delta-4isanisoformconstitutingasplicevariantofIL6thatlacksexon4.TheproteinlackstwoaminoacidsnecessaryforIL6homodimerizationandtwoofsixaminoacidsrequiredforinteractionwithIL6receptorbeta.ThisisoformformsastablecomplexwithIL6receptoralpha.IL6-Delta-4maycompetewithnativeIL6forbindingtotheIL6receptoralphaandregulateIL6bioactivitiesbecauseofitsinabilitytotransmitIL6receptorbeta-mediatedsignaling(Bihletal,2002).