CD4 and neoplasm: In support of this, the proliferation of CD4+ T cells and CD8+ T cells was reactivated in TLSs after deleting Treg cells by diphtheria toxin, causing enhanced tumor destruction.133 In a mouse lung adenocarcinoma model, the depletion of Treg cells increases CD4+ T cell and CD8+ T cell infiltration, especially in TLSs.