Pectin-guar gum-zinc oxide nanocomposite enhances human lymphocytes cytotoxicity towards lung and breast carcinomas

Highlights: • A novel PEC-GG-ZnO nanocomposite was synthesized with size range of 50-70nm. • PEC-GG-ZnO was capable of stimulating human lymphocytes proliferation. • PEC-GG-ZnO enhanced the expression of CD3, CD8, and CD56 on PBL and secretion of cytokines i.e. IFN-Y, IL-2 and TNF-α. • PEC-GG-ZnO enhanced cytotoxicity of activated human lymphocytes towards lung and breast carcinomas. - Abstract: Pectin-guar gum-zinc oxide (PEC-GG-ZnO) nanocomposite was prepared by precipitation technique. The composite was characterized by using FT-IR, XRD, HRTEM, SAED, EDS, and SEM. TEM images showed the hexagonal shape of nanocomposite with the size range of 50–70 nm. Further, PEC-GG-ZnO was used as an immunomodulator for the first time to improve the cancer cells killing capabilities of human peripheral-blood lymphocytes (PBL). The lymphocyte proliferation assay proved the immunostimulatory property of the PEC-GG-ZnO which increased with the increase in concentration (25 μg/ml to 200 μg/ml). ELISA detection confirmed a significant increase in the release of IFN-γ, IL-2 and TNF-α cytokines and flow cytometry analysis revealed enhanced expression of CD3, CD8, and CD56 after treating PBL with PEC-GG-ZnO as compared to PEC and GG treatment. Moreover, we also found that nanocomposite pretreated human PBL displayed enhanced cytotoxicity towards lung (A549) and breast carcinoma (MCF-7) cells as compared to untreated PBL. The microcytotoxicity assay also demonstrated that with increase in effector: target ratios from 2.5:1 to 20:1, there was an increase in the cancer cell death. Taken together, the current data corroborates the immunostimulatory activities of PEC-GG-ZnO, a novel nanocomposite, hence it can serve as a promising cancer therapeutic agent.