The immunotherapy uses the body’s immune cells or immune cells of a matched donor for the treatment of cancer and for some patients it yields good results in clinical trials.
Researchers from Washington University School of Medicine in St. Louis found that the effectiveness of immunotherapy depends on the age of immune cells. The natural killer (NK) cells, in their early development, are more effective and could be developed from human pluripotent stem cells without utilizing the cells from a matched donor or patient.
Detailed findings of this study are published in the journal “Developmental Cell.”
Research leader Christopher M. Sturgeon found that the effectiveness of natural killer cells is highly consistent and would not need cells from the patient or the donor. Researchers are working to increase the effectiveness of immunotherapy for cancer patients and revealed that these natural killer cells could be manufactured from the existing cell under strict guidelines and could be easily available for the patients whenever they need them.
Adult versions of natural killer cells originate from bone marrow and are used in investigational therapies while earlier natural killer cells form in the yolk sac of the early embryos of mammals. These earlier versions of NK cells are short-lived immune cells and can originate from human pluripotent stem cells for therapeutic purposes because these stem cells tend to produce different types of cells including NK cells.
Producing such cells from stem cells removes the time to utilize patient’s or donor’s cells and make it easily available for cancer patients.
Sturgeon found that in the early stage of embryo development, there is no bone marrow but still there is the production of blood. To keep the embryo alive, there is a brief supply of blood by the yolk sac until bone marrow starts the production of blood. These early blood cells seem to be capable of producing natural killer cells that adult blood cells cant produce.
Researchers tempted induced pluripotent stem cells of human and mouse to form specific natural killer cells and showed that these early versions of natural killer cells are better than adults ones in releasing anti-tumor chemicals through a process called degranulation.
The research team adds that adult version of natural killer cells provokes harmful inflammation by releasing different chemicals but unfortunately these chemicals are not helpful against cancer.
In the past work by other research groups, the origin of natural killer cells was a question mark. These groups suggested that early versions of natural killer cells are more helpful against cancer but how and why they were effective was unknown.
But now the origin of these unique natural killer cells is known. Natural killer cells could be originated from existing pluripotent stem cells and unlike T cell therapies, NK cells don’t harm healthy cells of body tissues. In case, if NK cells cause harm they do not stay longer in the body.
Sturgeon was interested to know the reason for their presence in the early embryo and assumed that during rapid cell division in the early embryo NK cells supervise the protection against infection or cancer. This study opens doors to manufacture early versions of NK cells from human pluripotent stem cells for clinical trials.