Researchers find cord blood cells can build a better human immune system into mice

Immunity plays a central role in the fight against cancer. Many of the current immunotherapies aim at helping the patient’s immune system to better recognize cancer cells—by using engineered antibodies—or by simply providing it with new cells, pre-equipped to search and destroy cancer. Either way, what is paramount is a deep understanding of how the immune system works and confronts tumors.

Unfortunately, the immune system is way too complex to model it in vitro or in a computer simulation, and animal experimentation is still unavoidable.

To this end, researchers have been using mice as a model organism for a long time. But not just any mice: to understand the human immune system, they build a brand-new model, using cord blood human cells, into mice with no immune system of their own.

Current methods are quite inefficient in the sense that they are either too slow or at higher risk of developing graft-versus-host disease—the transplanted immune cells attacking tissues—a life-threatening condition for the recipient mice.

To avoid these issues, a team from the Josep Carreras Leukemia Research Institute, spearheaded by Dr. Carla Panisello and supervised by Dr. Pablo Menéndez and Dr. Clara Bueno, have developed a new method based on human cord blood mononuclear cells. Their findings have been published in the Journal for ImmunoTherapy of Cancer.

This new experimental platform showed a superior ability to produce and sustain a balanced immune cell population, accurately representing the lymphoid and the myeloid immune lines. Also, since cord blood cells are immunologically naive—never been activated before—they tolerate mouse structures much better, resulting in the lowest rates of graft-versus-host disease.

Results confirmed that this new experimental model could deal with transplanted human hematologic and solid cancer cells much better than non-modified mice, with larger survival rates and a higher infiltration of immune cells into the tumors, mimicking a realistic immune response.

While these are just the first steps in this new experimental model, current results indicate that it could be a very promising system to better understand the inner workings of the immune system when facing cancer and developing new generations of immunotherapy, at the preclinical stage.