Immunostimulatory effect of chitosan conjugated green copper oxide nanoparticles in tumor immunotherapy

•CuONPs@CS was able to activate the macrophages that killed cancer cells.•Activated macrophages stimulated Th1 & Th2 cells.•Specific antigen conjugated CuONPs@CS functioned as an antigen delivery vehicle.•Antigen conjugated CuONPs@CS triggered cytotoxic T lymphocytes. Current study demonstrates the immunogenic role of biopolymer coated green synthesized copper oxide nanoparticles by the induction of cellular immunity through the activation immune cells. Alongside humoral immunity response was triggered by the surface coated NPs through IgG response which indicate the adjuvanic role of the nano conjugate. Th1 (Type 1 and Type 2 helper T cells) and Th2 cells were activated after the treatment with nano conjugate and act as an immunostimulant which would inhibit the proliferation of breast cancer (MCF-7) and cervical cancer (HeLa) cells in in vitro. Solid tumor induced by 4 T1 cells were also inhibited in in vivo Balb/C mice model. Secretion of pro-inflammatory cytokines and the increase in CD + 4 populations indicate the activation of immune cells in the current study. Immunotherapy by the help of metal nano conjugate can be an effective tool to eradicate the cancer cells from the system.