CD2 and neoplasm: Furthermore, we generated a new mouse model in which the gene Cx3cr1 was homozygously deleted and replaced with the diphtheria toxin receptor (DTR) in antigen-specific CD8+ T cells (Pmel-1 Cd2-cre/Cx3cr1DTR/DTR mice) to definitively assess the ability of intratumoral differentiation of tumor-specific CD8+ T cells in vivo.