Immunohistochemical analyses of SL3-3–induced tumors. (A) Sections of a representative tumor of the thymus stained with either H&E or antibodies against CD3ϵ (CD3), TdT, and myeloperoxidase (MPO). (B) Immunohistochemical stainings of CD3ϵ⁺ tumors from different animals for double fluorescent analysis of CD4 and CD8 expression. All of the samples shown were either CD3ϵ bright (nos. 160, 163, 407 all thymus) or CD3ϵ dim (no. 275; mesentery lymph node). The genotypes of the mice with the tumors shown are Nfatc3^-/- (nos. 160, 163, 407) and Nfatc2^-/- (no. 275). Images were acquired with Leica TCS SP2 Confocal System equipped with a Leica DMRE microscope with an HCX PL APO 40×/1.25 NA oil CS objective lens. Images were processed with Leica Confocal Software version 2.61 (all from Leica Microsystems, Mannheim, Germany).