CD4 and neoplasm: Indeed, Schreiber et al. have shown that, if purified polyclonal tTreg and Tconv, differentially labeled with green or red fluorescence, were co-transferred in CD4-null mice, the tTreg progeny exceeded the newly Tconv-derived pTreg population in tumor-draining lymph nodes as well as in the spleen; conversely, when transgenic, tumor-antigen-specific, tTreg and Tconv were injected, tTreg and pTreg reached comparable frequencies in tumor-draining lymph nodes (107).