Length of the antibody heavy chain complementarity determining region 3 as a specificity-determining factor
Fecha
2004Resumen
Theantigenbindingsiteofanantibodyismadeupofresiduesresidinginsixhypervariableloopsof the heavyandlightchains.Inmostcasesseveraloralloftheseloopsarerequiredfortheestablishmentofthe antigen-bindingsurface.Fiveoftheseloopsdisplayalimiteddiversityinlengthandsequencewhilethethird complementaritydeterminingregion(CDR)oftheheavychainishighlydifferentbetweenantibodiesnot onlywithrespecttosequencebutalsowithrespecttolength.Itsextensivediversityisakeycomponentinthe establishmentofbindingsitesallowingfortherecognitionofessentiallyanyantigenbyhumoralimmunity. Therelative importanceof its sequencevs its lengthdiversity inthiscontext ishowever, notverywell established.Toinvestigatethismatterfurtherwehaveusedanapproachemployingcombinatorialantibody librariesandantigen-specificselectioninthesearchforCDRH3lengthandsequencediversitycompatible withagivenantigenspecificity,themajorantigenicdeterminantonthetumour-associatedantigenmucin-1. InthiswaywehavenowdefinedheavychainCDR3lengthasacriticalparameterinthecreationofan antigen-specificbindingsite.Wealsoproposethatthismayreflectadependenceofaparticularstructureof thishypervariable loop, themajorcarrierofdiversity inthebindingsite, forestablishmentofagiven specificity