Characterization of the cells of p635-649–specific clone 60. (A) Expression of HLA-DR molecules on the surfaces of the CD4⁺-gated cells before in vitro stimulation with SCP1-derived peptides. (B) Expression of HLA-DR on the CD4⁺-gated cells of clone 60 (which made up 96% of this clone) demonstrated the strong activation of these T cells on stimulation with p635-649. (C) Phenotype of the CD4⁺-gated cells of clone 60 (CD45 RA^–/CCR7–) corresponded to the effector-memory type, according to the classification scheme suggested by Sallusto et al.³²