
Description:
AntibodiesagainsttheSmantigensofthesmallnuclearribonucleoproteins(snRNPs)areaveryspecificMarkerforthediagnosisofsystemiclupuserythematosus(SLE).AntibodiesagainsttheSmproteinsarefoundin20-30%ofSLEpatients.Anti-SmantibodiesareobservedatahightiterintheactiveperiodofSLEandatalowtiterinthenon-activeperiod.AntibodiesdirectedagainstSmproteinsaswellasDNAfoundinserafrompatientswithSLEhavebeenincludedasoneoftheAmericanCollegeofRheumatologyclassificationcriteriaforSLE.Smantigenisnowknowntobeconsistedofatleastninedifferentpolypeptides.Anti-SmantibodiesarepredominantlydirectedagainsttheSmD1proteinofthesnRNPcomplex.Principle:
AutoimmuneELISAkitsmeasureautoimmuneantibodiesintheserum.Itisbasedontheprincipleofasolidphaseenzyme-linkedimmunosorbentassay.Theassayutilizesaspecificantigenforimmobilizationonthemicrotiterwellsandanti-humanIgGantibodyconjugatedtohorserADIshperoxidase(HRP)fordetection.Thetestsampleisallowedtoreactsimultaneouslywiththetwocomponents,resultingin autoimmuneantibodiesbeingsandwichedbetweenthesolidphaseandenzyme-linkedantibodies.Afterincubation,thewellsarewashedtoremoveunbound-labeledantibodies.AHRPsubstrate,TMB,isaddedtoresultinthedevelopmentofabluecolor.ThecolordevelopmentisthenstoppedwiththeadditionofStopSolutionchangingthecolortoyellow.Theconcentrationofautoimmuneantibodies isdirectlyproportionaltothecolorintensityofthetestsample.Absorbanceismeasuredspectrophotometricallyat450nm.