Stimulatory cell lines for ex vivo expansion and activation of natural killer cells

A genetically engineered cell population that does not express major histocompatibility complex (MHC) I molecules,

• wherein said genetically engineered cell population is derived from K562 cells,
• wherein said genetically engineered cell population is modified to express membrane-bound interleukin-15 (mbIL15), wherein the mbIL15 is encoded by a nucleic acid sequence that comprises SEQ ID NO:
• 1,
• wherein said genetically engineered cell population is modified to express membrane-bound 4-1BB ligand (mb4-1BBL) comprising the amino acid sequence of SEQ ID NO:
• 14,
• wherein said genetically engineered cell population is modified to express membrane-bound interleukin-18 (mbIL18), wherein the mbIL18 comprises the amino acid sequence of SEQ ID NO:
• 8,
• wherein said genetically engineered cell population is modified to express membrane-bound interleukin-12A (IL12A), wherein the mbIL12A comprises the amino acid sequence of SEQ ID NO:
• 4,
• wherein said genetically engineered cell population is modified to express membrane-bound interleukin-12B (IL12B), wherein the mbIL12B comprises the amino acid sequence of SEQ ID NO:
• 6,
• wherein said genetically engineered cell population does not express major histocompatibility complex (MHC) I molecules, and
• wherein co-culture of said genetically engineered cell population with a population of natural killer (NK) cells results in the activation and expansion of the NK cells.