Phosphotyrosine NF-kB NF-kB Phosphotyrosine Phosphotyrosine Phosphotyrosine Phosphotyrosine Phosphotyrosine Phosphotyrosine Phosphotyrosine Phosphotyrosine Phosphotyrosine IkB Akt PKC LCk Lck Zap-70 SLP-76 Lat CD4 CD40 CD80 CD86 CD28 CD45 ICOSL ICOS IL-2 TRIM MHC Class II CD154 IL-2R IL-4 IL-5 IL-6 IL-10 IFN-y TCR CD3 ICos-ICosL Pathway in T-Helper Cell