CD4 and breast cancer: Dey et al. (24) found that chitosan conjugated green copper oxide nanoparticles (50 μg/mL) inhibited the proliferation of breast cancer and cervical cancer cells in vivo in a Balb/C mouse model, and increased pro-inflammatory cytokines and CD4+ populations; the author showed that the potential mechanism of chitosan conjugated green copper oxide nanoparticles is not only through inducing cellular immunity by activating immune cells, but they also lead to a humoral immune response through an IgG reaction.