The invention provides a construction method and application of a
gene modified K562
cell line, and belongs to the technical field of biological medicines. According to the invention, two viruses CD86-4-1BBL and mbIL-21 are respectively subjected to
gene transduction packaging by adopting a third-generation
lentivirus four-
plasmid packaging
system, a K562
cell line is infected by the lentiviruses CD86-4-1BBL and mbIL-21, and a
monoclonal cell line capable of stably expressing CD86, 4-1BBL and mbIL-21 proteins is obtained through screening. According to the method, cell lines with the
cloning numbers of V5-E9, V10-A5, V5-D6 and V6-D7 are obtained through screening, the four
cloning cell lines can serve as feeder cells for stimulating NK cell amplification after being amplified and subjected to
irradiation treatment, NK cell amplification can be effectively promoted, the amplification multiple of the NK cells reaches up to 6000-8000, and large-scale preparation and production of the NK cells for treatment are met.