Results of the St. Jude study are published in the current online issue of Blood.
The researchers demonstrated how to overcome significant technical hurdles that have until now slowed development of NK-based therapies for ALL, according to Dario Campana, M.D., Ph.D., a member of St. Jude Hematology-Oncology and Pathology, and senior author of the Blood report. Progress in adapting NK cells to the treatment of ALL had been significantly hampered because researchers were not able to grow large numbers of these immune cells in the laboratory, and because NK cells normally have only weak anti-leukemic activity.
The key breakthroughs made by the St. Jude team were the development of a laboratory technique for rapidly producing a large, pure population of NK cells from a small sample of blood; and developing a technique for genetically modifying NK cells so that they would become potent killers when they encountered leukemic cells.
In order to grow large populations of NK cells, the team started with samples of blood containing a variety of different immune system cells. They placed this sample into a dish containing a type of human leukemia cell called K562. Campana's team genetically modified the K562 cells so they carried on their surfaces many copies of two different proteins, 4-1BBL and IL-15. The genetically modified K562 cells quickly stimulated the expansion of the NK cell population to more than10,000 times their original number. The technique triggered growth of NK cells specifically, which greatly simplified the ability of the researchers to collect a pure popu
Source:St. Jude Children's Research Hospital