What is a Natural Killer Cell?

Natural killer cells (NK) are important immune cells in the body. They are not only related to anti-tumor, anti-virus infection and immune regulation, but also participate in the occurrence of hypersensitivity and autoimmune diseases in some cases. Target cells, killing media.

Natural killer ce (NK cells) derived from bone marrow lymphoid

NK cells exact

versus

The zeta chain of the CD3 molecule

NK cells do not express the TCR / CD3 complex, but some NK cells express the CD3 chain. When NK cells are activated with CD16 antibodies, the chain undergoes tyrosine phosphorylation, which causes an increase in intracellular Ca2 + concentration and IP3 levels. Promote cytokine synthesis and

Natural killing activity

Since the killing activity of NK cells is not restricted by MHC and is independent of antibodies, it is called natural killing activity. NK cells are rich in cytoplasm and contain large

Chinese name

Determination of natural killer cell activity

[Overview]

Natural killer cells (NK) mediate the natural immune response. It does not rely on antibodies and complements, that is, it can directly kill target cells, such as tumor cells or virus-infected cells. In addition, it has immunoregulatory functions and also participates in transplant rejection And the development of certain autoimmune diseases.

Reference

51Cr release method: The natural release rate is <10% to 15%; the natural killing rate is 47.6% to 76.8%; the utilization rate of 51Cr is 6.5% to 47.8%. Enzyme release method: The cytotoxicity index is 27.5% 52.5%. The flow cytometry method was 13.8% ± 5.9%.

[Clinical significance]

NK cell activity can be used as one of the indicators to judge the body's anti-tumor and anti-viral infection. In patients with hematological tumors, solid tumors, immunodeficiency diseases, AIDS, and certain viral infections, NK activity is reduced; host anti-graft responders have increased NK activity.

Dr. Campana of St. Zude Children's Research Hospital and others published a paper in the new issue of the online edition of "Blood" magazine, saying that the previous research on the use of natural killer cells to treat leukemia is not progressing, mainly because natural killer cells do not affect leukemia cells. Sensitive and difficult to cultivate in the laboratory in large numbers, and they have made progress in both areas.

The researchers first used blood samples containing various immune cells and cultured them with genetically modified K562 human leukemia cells. After being transgenic, this leukemia cell has two proteins, "4-1BBL" and "IL-15" on its surface. Researchers have found that transgenic leukemia cells can stimulate a large number of natural killer cells in blood samples, and their number quickly reaches 10,000 times the original, which allows natural killer cells to be purified.

Since then, researchers have genetically modified natural killer cells to produce receptor proteins that recognize leukemia cells on their surfaces. This receptor protein binds to the protein "CD19" on the surface of leukemia cells, prompting natural killer cells to lyse the leukemia cells.

Campana et al. Stated in their paper that their method can cultivate a large number of natural killer cells from a small number of blood samples, so that the natural killer cells can be practically applied to leukemia treatment, which is especially suitable for leukemia patients undergoing bone marrow transplantation. Doctors can use blood samples from bone marrow donors to grow large numbers of genetically modified natural killer cells, and then inject them into patients undergoing bone marrow transplantation after transplantation to destroy the remaining leukemia cells.

Researchers say they will soon conduct clinical trials in children with acute lymphoblastic leukemia. If the trial shows positive results, this method will become one of the weapons for leukemia treatment ^[2] .