The second day of the three-day Stem Cell Meeting on the Mesa in La Jolla always ends with a public lecture. This year that slot featured no-longer-rising-star, but rather risen star, Jennifer Elisseeff, of Johns Hopkins. She provided a powerful reminder of the power of interdisciplinary research teams. Her career has always mingled cell biology, chemistry and engineering, but the highlight of her talk required her to take a sabbatical and learn more about immunology.As director of the Hopkins’ Translational Tissue Engineering Center she has worked on complex tissue replacements for several areas of the body, with extensive work in knee damage and in and around the eye. She concentrates on the interplay of nature and nurture at the cellular level. In essence she looks at the dynamics of what genes are turned on in a cell and the role of the surrounding materials. When this is at work in a tissue-engineered implant it involves the interplay between cells and some sort of scaffold to hold them in place. In addition she finds added nuance to this exchange when mixing synthetic and natural scaffold materials.
“We are learning how these material talk to each other in a dish, but we need to know how this relates to what happens in the body.”
What surprised her in her findings was the powerful role of immune cells summonsed to an implant. Often times, in cell therapies the immune system is cast as a bad actor just working to reject the foreign cells. She found that one type of immune cell in particular, the macrophage, has two modes of operation. It can have a damaging inflammatory response or a reparative response. The toggle that can switch the macrophages from one form to the other turns out to be another immune cell, a particular type of T cell called a CD4.
Elisseeff called for the research community to become active in a sub-discipline Regenerative Immunology. She said that if we can empower the immune system’s beneficial affects, we can dramatically improve the value of tissue implants. She briefly described a study in which she enlisted the right T cells in mice to direct the macrophages to a reparative response. The result: tissue implants produced a better muscle repair.
CIRM co-sponsors the Mesa meeting along with the Alliance for Regenerative Medicine and the Sanford Consortium for Regenerative Medicine. The latter hosted the public talk in the auditorium named in honor of Duane Roth, the former vice chair of our board who died in a tragic bike accident a few years ago. He would have been proud of the standing-room only crowd and of Elisseeff’s admonishment for various fields to work together early with an aim to accelerate getting products to patients.