BackgroundInformation | CD11bisthe165kDaα-chainoftheMac-1complex.Themolecule,alsocalledCR3,functionsasacellsurfacereceptorfortheC3bicomplementfragment.ThereisevidencethatCD11bcanbindfibrinogeninadditiontoC3bi(Wright,1988).Twobindingsiteshavenowbeenreported,onerecognizinglipopolysaccharide,andtheotherproteinligandscontainingthearg-gly-aspsequence(Wright,1989).BindingofthecoagulationfactorXhasalsobeensuggestedasanadditionalreceptorroleofCD11b(Altieri,1988).ThisproteinbelingstoafamilyofrelatedheterodimericproteinsdesignatedCD11intheclassificationsystemforhumanleucocytedifferentiationantigens,whichsharesacommonβ-chainwithaMWof95kDa(CD18).BesidestheC3bireceptor,thisproteinfamilycontainstwoothermembers,leucocytefunctionassociated-1(LFA-1,C11a)antigenandp150,95protein(CD11c)(Sanchez-Madrid,1983). |