The invention discloses a multifunctional immunomodulatory
fusion protein, a preparation method thereof, an NK
cell for expressing the
protein and application. The structure of the
fusion protein is anti-CD16a VHH-(GGGGS) 3-anti-NKG2D VHH-(EAAAK) 2-IL-15R beta super
agonist peptide, and the
amino acid sequence of the
fusion protein is SEQ ID NO: 1. Wherein the anti-CD16a VHH and the anti-NKG2D VHH synergistically activate the
immune effector cells, the IL-15R beta super
agonist peptide strongly activates the
effector cells and weakly activates the Treg, and the
linker ensures that each structural domain is independent in function. The
protein can be efficiently prepared, the yield is 155mg / L, the purity is more than 95%, NK cells and CD8 + T cells can be obviously activated, the in-vitro
cracking rate of various
tumor cells in 24 hours reaches 87.0-90.0%, the in-vivo
tumor growth is obviously inhibited, the inhibition rate is 81.3%, and the lifetime of tumor-bearing mice is prolonged by more than 60 days. The stability of NK cells expressing the
protein is improved after MI-3 treatment, and efficient and safe candidate drugs are provided for tumor
immunotherapy.