Microbe Complement Bound activation C3d CR2 Recognition CD19 by b cells Iga/B CD81 Signals from Ig and CR2 complex B cell activation CElsevierAbbas&Lichtman:BasicImmunologyUpdated2e-www.studentconsult.coml The role of coreceptor(CD19/CD21/CD81)in B cell activationThe role of coreceptor (CD19/CD21/CD81) in B cell activation