Usingtwo-colourflowcytometry＞200antibodiessubmittedtothe8thInternationalWorkshopofHumanLeukocyteDifferentiationAntigens(HLDA8)havebeenanalyzedfortheirreactivitywithrestingandactivatedCD203c+basophils.Fourantibodieseithernon-reactiveorweaklyreactivewithrestingbasophilsexhibitedanincreasedreactivitywithbasophilsactivatedbyanti-IgE-mediatedcross-linkingofthehighaffinityIgEreceptor(FcεRI).TheseincludeantibodiesagainstCD164(WS-80160,cloneN6B6andWS-80162,clone67D2),aswellastworeagentswithpreviouslyunknownspecificitiesthatwereidentifiedasCD13(WS-80274,cloneA8)andCD107a(WS-80280,cloneE63-880).Theactivationpatternsfollowedeitherthe'CD203c-like'or'CD63-like'activationprofile.TheCD203cprofileischaracterizedbyarapidandsignificantupregulation(ofCD13,CD164,andCD203c),reachingmaximumlevelsafter5-15minofstimulation.ThePhosphoinositide-3-kinase(PI3K)-specificinhibitorWortmannininhibitedtheupregulationofthesemarkerswhereas12-O-tetradecanoyl-phorbol-13-acetate(TPA)inducedarapidandFcεRI-independentupregulationwithin1-2min.IntheCD63profile,maximumupregulation(ofCD63andCD107a)wasdetectedonlyafter20-40min,andupregulationbyTPAreachedmaximumlevelsafter60min.Insummary,ourdataidentifyCD13,CD107a,andCD164asnovelbasophil-activationantigens.Basedontimekineticsofupregulation,wehypothesizethatmoleculesofthe'CD203cgroup'andthe'CD63group'arelinkedtotwodifferentmechanismsofbasophilactivation.
