
Cataloguenumber
CYT-269
Synonyms
IGIF,IL-1g,IL-18,IL1F4,MGC12320,IFN-gamma-inducingfactor,Interleukin-1gamma,IL-1gamma,Iboctadekin.
Introduction
Description
Interleukin-18HumanRecombinantproducedinE.Coliisasingle,non-glycosylatedpolypeptidechaincontaining157aminoacidsandhavingamolecularmassof18.2kDa.TheIL-18ispurifiedbyproprietarychromatographictechniques.
Source
PhysicalAppearance
Formulation
Lyophilizedfromaconcentrated(1mg/ml)solutioninPBSandDTT.
Solubility
ItisrecommendedtoreconstitutethelyophilizedInterleukin18insterile18MΩ-cmH2Onotlessthan200µg/ml,whichcanthenbefurtherdilutedtootheraqueoussolutions.
StABIlity
Purity
Greaterthan95.0%asdeterminedbySDS-PAGE.
BiologicalActivity
TheED50is1.5-9ng/mLandismeasuredbyInterleukin18abilitytoinduceIFN-γsecretionbyKG‑1humanacutemyelogenousleukemiacellsinthepresenceofTNF-alpha.
References
1.Title:DiscoveryofIL-18AsaNovelSecretedProteinContributingtoResistancebyComparativeSecretomeAnalysisofMCF-7andMCF-7/Dox.Publication:YaoL,ZhangY,ChenK,HuX,XuLX(2011)DiscoveryofIL-18AsaNovelSecretedProteinContributingtoResistancebyComparativeSecretomeAnalysisofMCF-7andMCF-7/Dox.PLoSONE6(9):e24684.doi:10.1371/journal.pone.0024684Link:http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0024684
Usage
SafetyDataSheet
SDS
Background
AlsoknownasIFN-gammainducingfactor,Interleukin-18orIL18isaprotein.InhumansthisproteinisencodedbytheIL18gene.Theproteinisaproinflammatorycytokine.
MechanismThelevelsofIL-18inthehumanbodyareincreasedatsitesofinflammation.Thisincludescasesofrheumatoidarthritisaswellasothersimilarconditions.Osteoblasticcellsexpresstheproteinanditiscapableofinhibitingosteoclastformation.Itisabletodothisthroughavarietyofmechanisms.Forinstance,itisabletostimulateGM-CSF.ThisiscreatedbyTcellsandisaresponsetotreatmentusingIL-18.Aswellasthis,thecytokinedoesstimulateINF-yproductionthroughvivoinbone.FurThermore,theimpactonboneresorptionandosteoclastogenesisisincreasedwhenusedinconjunctionwithIL-12treatment.StudieshaveshownthatIL-18providesanindirectstimulusonosteoclastogenesisduetotheeffectithasonTlymphocytes.Furthermore,evidencehasshownthatIL-18doesincreasetheproductionofOPG.ThiswasstudiedinresearchontransgenicmicethatoverexpressedIL-18.Inthesecasesosteoclastsdecreasedasdidbonemass.ThissuggestedthatIL-18alsohasanimpactonbonegrowth.InteractionsResearchhasalsoexploredthedifferentinteractionsofIL-18onotherproteins.ThisincludestheinteractionbetweenIL-18andIL-18R.Thishasbeenshowntodecreasethepowerofprotectiveimmunityandincreasepathogenicresponsesduringaninfectioninvolvingintracellularbacteria.ThisinteractionsuggeststhatthepresenceorabsenceofIL-18Rsignaldoesimpactthepathogeniccomparedtoprotectiveimmunity.Anotherinteractionbetweeninterleukin19andAstrocytehasshownthatitcanimproveneuropathicpainprocessingfollowingnerveinjury.Itisproposedthisisduetothefactthatthenociceptivesignalsinthespinalcordareaugmentedduetothisreaction.FunctionBelongingtotheIL-1superfamily,thiscytokineisproducedbymacrophagesaswellasvariousothercells.Itoperatesafterbindingwiththeinterleukin-18receptor.WorkingwithIL-12,theproteinisthenabletoinduce-cellmediatedimmunityafteraninfectionfromlipopolysaccharideandothermicrobialproducts.OncestimulatedbyIL-18othercellsincludingnaturalkillerandTcellsthenreleaseIFN-y.ThistypeIIIFNplaysacrucialpartinactivatingthemacrophagesofvariousothercells.TogetherIL12andIL-18areabletosuccessfullyinhibitIgEandIG1productionthatisdependentonIL-4.Aswellasthis,theproteinisalsoabletoincreaseIgG2aproductionthroughBcells.IL-18willinteractspecificallywiththistypeofcytokineandhasanegativeimpactonregulationofbiologicalactivity.StructureManyresearchershavesuggestedthatthestructureofIL-18isakeywaytounderstandit’sreceptoractivationmechanism.ThestructureofIL-18closelyresemblesofIL-1andhasvarioussimilarities.Itisfoldedintoabeta-trefoilstructureandthreesiteshavebeenshowntobeimportantforreceptoractivation.Thesewererevealedthroughextensivemutagenesis.TwoofthesitesprovidebindingsitesfortheIL-18receptorandarelocatedinpositionssimilartoIL-1.ThethirdstructureseemstobeusedforIL-18receptorbetabinding.