The T lymphocyte (T cell) is a very important white blood cell; found in the immune system it is capable of directly attacking infections or cancer and controlling other cells. Czerniecki’s work has shown that T cell subtype Th1 is critical for successful immunity against cancer in particular and is unique in its ability to produce a factor called interferon gamma (IFN-γ).
A regulatory T cell (Treg) can switch off strong immune responses during repair or keep the immune system in check to prevent autoimmune disease, however cancer cells have evolved to subvert such regulatory powers. In fact, tumors recruit Tregs to protect their own defenses from the immune system.
Dr. Czerniecki’s vaccine strategy is centered on a white blood cell called a dendritic cell (DC). DCs collect information on potential dangers to the body and present these to T cells. The T cells then decide how best to deal with the threat. By extracting DCs from cancer patients, Dr. Czerniecki was able to infect them with the cancer so when inserted back into the body Th1-type T cells embarked on a search and destroy mission against any cell bearing the cancer proteins presented by the DC.
It had been a concern that despite the tumor’s line of Treg bodyguards might effectively blunt the attack. However, Dr. Czerniecki and his team have shown that this might not be the case. When Treg cells and normal T cells were incubated together in the test tube, as expected, Treg cells prevented regular T cell activity. Interestingly, when DCs were added, regular T cells regained their function and the cease and desist orders typical of Tregs appeared to be annulled. Looking more closely, the team was surprised to find that Tregs were no longer looking or behaving like Treg. Instead, they were taking on the character of the cancer-fighting Th1 cells, and were even making IFN-γ. The vaccine DCs turned the pacifists into fighters!