Because everyone’s immune system is different, it’s impossible to predict with absolute certainty how any given person will react to a specific medication. In the not-too-distant future, however, at-risk patients may get their own custom-altered mouse, with an immune system that’s a copy of their own. Medications could be tried out on the mouse first, and if it showed no adverse reactions, then the person could receive them. If the person had an autoimmune disease, the mouse could also provide valuable insight into its treatment. A team led by Columbia University Medical Center’s Dr. Megan Sykes has recently developed a method of creating just such a “personalized immune mouse.”
The process begins by transplanting bone marrow stem cells from the human subject, along with a one-cubic-millimeter chunk of their thymus tissue, into a mouse with a disabled immune system. The thymus is an organ in the immune system, and the sample of it is implanted in the mouse’s kidney capsule, which is a thin membrane surrounding the kidney.
It incubates there for six to eight weeks, within which time it becomes seeded with the stem cells, which have been circulating in the mouse’s bloodstream. This in turn causes it to create a number of types of human immune cells, resulting in “a robust and diverse human immune system” matching that of the donor. Previous efforts have reportedly not been successful in creating a complete system, or have been hampered by the mice rejecting the human material.
Besides being used to test responses to medications, the personalized immune mice might also play a key role in developing individualized immunotherapies. These would allow patients to more successfully fight infections or cancer, or to accept transplanted tissue.
Additionally, Dr. Sykes plans on using the mice for research into type 1 diabetes, to determine how diabetic patients’ immune systems are different from those of non-diabetics, before the disease develops.
A paper on the research was recently published in the journal Science Translational Medicine.