Researchers have been able to produce genetically modified natural killer cells that are highly efficient in eliminating cancer cells and in a faster time than traditional immunotherapy methods.
Researchers from Harvard University and the Massachusetts Institute of Technology in the United States have developed a new method of genetically engineering natural killer cells with chimeric antigen receptor (CAR) natural killer cells, making them more effective in fighting cancer cells without the immune system attacking them.
The results of the study were published in the journal Nature Communications on October 8, 2025, and were written about by the York Alert website.
This new method could facilitate the development of a pre-prepared treatment that can be used immediately after a cancer patient is diagnosed. Previous methods of chimeric antigen receptor (CAR) therapies for T cells or natural killer cells required several weeks in the laboratory before they were ready for use.
Genetically modified cell technologies in treating cancer face many challenges, the most notable of which is that they require a long period of time to produce a sufficient number of cells. In addition, the cells extracted from the patient’s blood are not as efficient as the cells found in a healthy human body.
The problem with extracting cells from another patient’s body is that the immune system rejects them. It recognizes them as foreign cells and gets rid of them before they accomplish their mission of killing cancer cells.
Killer cells
Natural killer cells are considered one of the most important parts of the immune system in the human body, and they play a major role in identifying and eliminating cancer cells and cells infected with viruses.
It does this by secreting a protein called perforin, which can make holes in the cell to be eliminated and trigger cell death in a process known as degranulation.
To obtain natural killer cells with chimeric antigen receptors, doctors first take a blood sample from the patient, then isolate natural killer cells from the sample and modify them to add the chimeric antigen receptor.
This receptor can recognize distinct proteins found on the surface of cancer cells, facilitating the process of eliminating cancer cells by natural killer cells.
Genetically modified natural killer cells need weeks of multiplication in the laboratory until they are ready for treatment to be transferred into the patient’s body, but this technology is still in the clinical trial stage.
A similar method of producing modified T cells has been adopted in the treatment of some blood cancers such as leukemia and lymphoma.
Escape from the immune system
In this study, scientists were able to overcome the problem of the immune system’s attack on modified natural killer cells, by silencing the genes responsible for the production of one of the proteins found on the surface of natural killer cells from the donor’s blood, known as the HLA class 1 protein.
Scientists were able to add genes that increase the efficiency of fighting cancer and avoid recognition by the immune system. To simplify the process of genetic modification to natural killer cells, scientists added all these genetic changes to a piece of DNA.
Scientists tested the new technology on mice that have an immune system similar to humans, and then they were injected with lymphoma cells. Natural killer cells with genetically modified chimeric antigen receptors in the study were able to eliminate cancer cells.
In contrast to natural killer cells that were not genetically modified or to which chimeric antigen receptors were added without removing the HLA class I protein from the surface of the donor cells, the cells could not withstand the immune system and the proliferation of cancer cells increased.
The researchers hope that the current study will move to the stage of clinical trials on humans, and replace current treatments that have poor effectiveness in treating lymphoma and other cancers in the future. This discovery may pave the way for a treatment for some autoimmune diseases such as lupus.