Dr Huntington said the research revealed that a protein called BCL-2 was particularly important for controlling the reservoir of NK cells in our body. BCL-2 is a so-called 'pro-survival' protein that makes normal immune cells survive for extended periods. Boosting NK cell numbers by treating them with IL may be a valuable new approach to boosting our immunity to viral infections or cancer. On the flipside, targeting this growth factor or BCL-2 could reduce NK cell numbers and offer potential therapies for immune disorders such as some types of autoimmune diseases, sepsis or graft versus host disease, a side effect of bone marrow transplants.
The team's research also identified that NK cells may be vulnerable to new medicines that inhibit BCL-2, which are also becoming widely tested as anti-cancer treatments. Materials provided by Walter and Eliza Hall Institute. Note: Content may be edited for style and length.
Science News. Researchers are also developing treatments to activate NK cells using small molecules or cytokines, and even testing genetically modified living NK cells as therapies. Register Log in. Bitesize category Cells: Bite-sized Immunology.
Related Articles Basophils. B Cells. Dendritic Cells. Dendritic Cells Tissue-specific. Mast Cells. Unlike T cells, which multiply profusely in order to eliminate infected or diseased cells, NK cells decline to proliferate when infused into patients.
This can put them at a sizable disadvantage. A second shortcoming is the fleeting lifespan of NK cells. The differences between T cells and NK cells reflect their very different roles in the immune system's response to disease. NK cells are part of the innate immune system, which handles diseases and infections the body hasn't encountered before.
Because they don't rely on a small subset of cells that "remember" previous infections and must proliferate in order to quell new infections, NK cells are ready to attack at a moment's notice. In this regard, NK cells' refusal to proliferate is a major asset: They essentially sacrifice numbers for speed. T cells, by contrast, are part of the adaptive immune system.
They learn from experience. When they defeat an infectious agent, such as a specific type of bacteria or virus, they're equipped to recognize and battle that agent whenever it returns to the body. This isn't to say that NK cells are indiscriminate defenders — that, like ill-trained watchdogs, they'll attack any type of intruder.
Instead, they take a more targeted approach, just as T cells do. T cells identify infected or cancerous cells based on bits of proteins contained in structures called MHC class I molecules on the surface of many diseased cells.
Romee explains: "Infected or cancerous cells oftentimes have a certain group of molecules on their surface yelling for help, saying, basically, 'We are infected, we are malignant, we have stress in our nucleus or genes. The differing roles of NK cells and T cells reflect the hand of evolution. Malignant cells often try to avoid a T-cell attack by shedding their MHC class I molecules — the external signs that they are cancerous.
This may provide a brief reprieve, but it ultimately lands them in a trap set by the immune system, for an absence of these complexes is precisely what spurs NK cells to go on the attack.
For all their potential, NK cells carry several liabilities as potential workhorses of cancer therapies — namely, their lack of staying power and failure to proliferate when infused into a patient. Their prospects brightened considerably, however, as a result of a series of recent discoveries. Natural killer NK cells are a distinct type of white blood cell, shown here attacking a cancer cell. In the mids, researchers at Washington University found that exposing mouse NK cells to cytokines — immune-signaling substances — endowed them with memory-like properties.
In , Romee and his associates demonstrated the same effect in human NK cells. The enhanced cells, dubbed "memory-like NK cells," behave much like T cells. Research into memory-like NK cells is at an early stage and much remains to be learned about their capabilities and limitations, but their promise is unmistakable.
The recipe for making memory-like NK cells is fast and simple.
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