Type IV hypersensitivity is a cell-mediated immune reaction. In other words, it does not involve the participation of antibodies but is due primarily to the ...TypeIVhypersensitivitySectionsDirectoryReferencesTypeIVhypersensitivitymedicineShareShareSharetosocialmediaFacebookTwitterURLhttps://www.britannica.com/science/type-IV-hypersensitivityLearnaboutthistopicinthesearticles:majorreferenceInimmunesystemdisorder:TypeIVhypersensitivityTypeIVhypersensitivityisacell-mediatedimmunereaction.Inotherwords,itdoesnotinvolvetheparticipationofantibodiesbutisdueprimarilytotheinteractionofTcellswithantigens.Reactionsofthiskinddependonthepresenceinthecirculation…ReadMoreallergiesInallergyDelayed,ortypeIV,allergicreactionsarecausedbytheactionsofTcells,whichtakelongertoaccumulateatthesitewheretheantigenispresentthandoB-cellantibodies.Theallergicresponsesappear12to24hoursormoreafterexposuretoanappropriateantigen.…ReadMoreInhumandisease:AllergiesTypeIVhypersensitivity,unliketheotherreactions,doesnotinvolveantibodiesbutinsteadismediatedbyTcells.Inthesereactions,alsocalleddelayed-typebecausetheyariseinamatterofdaysratherthanminutesorhours,Tcellseitheractivatealocalinflammatoryreaction,…ReadMorecontrastwithatopyInatopy…contrastedwiththeconditioncalleddelayedhypersensitivity,inwhichallergicsymptomstakehoursordaystodevelop.Seealsoallergy.ReadMorepoisonsandpoisoningInpoison:AllergiesDelayedhypersensitivitydiffersfromothertypesinnotinvolvinghumoralimmunity.Uponreexposuretotheallergen,sensitizedT-lymphocytesreleaselymphokines,whichtriggeraseriesofinflammatoryreactions.Theinflammationleadstothedevelopmentofallergiccontactdermatitisintheskinandachronicformof…ReadMore