We uncovered a significantly increased NK cell killing activity due to 1 h zinc pre-incubation and contact to zinc-rich medium in physiological concentrations. Moreover, co-stimulation of zinc and IL-2 provoked an additive increase in NK cell killing activity. In contrast, zinc deficiency induced by 1 h TPEN pre-incubation significantly decreased the killing activity of primary NK cells.
https://www.sciencedirect.com/science/article/abs/pii/S1756464618303621
a disturbance in zinc homeostasis would explain why killing is reduced if zinc supply is limited and increased if additional zinc is supplied. NK cell function was weakened when zinc signals are absent. zinc supplementation increased differentiation of CD341 progenitors toward NK cells and their cytotoxic activity, as well as NK killing activity, and intracellular perforin concentrations
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5748737/
NK cells are able to destroy transformed or infected cells, largely due to recognition of changes in major histocompatibility complex MHC-I composition that are caused by the degeneration or the pathogen. In contrast, regular cells are protected from killing by NK cells as long as they carry surface MHC-I, which is bound by the killer cell inhibitory receptor (KIR) on NK cells. To form the so-called NK cell synapse, KIR multimerization is essential, and was shown to be zinc-dependent
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5748737/
Thymosin alpha 1 restores NK-cell activity and prevents tumor progression in mice immunosuppressed by cytostatics or X-rays https://pubmed.ncbi.nlm.nih.gov/6553515/
LL-37 improves CpG delivery to intracellular TLR9 results in the enhanced proliferation and activation of NK cells, The findings indicate the significance of cathelicidin to NK cell function and in vivo tumor defense. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7246396/