The dendritic cells now know to distinguish between tumor cells and normal cells and can teach this to the white blood cells known as T-cells. The T-cells then roam the body, and like Pac-Man can find and destroy breast cancer cells. T-cells commonly are used by the immune system to root out infection.
Emens' vaccine is made at a Food and Drug Administration-approved laboratory two floors below her office in a first-of-its-kind facility at a university. The manufacturing process scales up the procedure Emens painstakingly did in her own laboratory when she created the vaccine. Whereas she did 100 million cells, the facility can grow 20 billion to 30 billion cells, enough to make vaccine for 25 patients.
All those cells are grown in a series of temperature- and humidity-controlled clean rooms, occupied by workers protected by gowns and gloves from head to toe. The first time a batch of vaccine was made for Emens in 2003, the facility created a master cell bank from the genetically modified cell lines Emens fashioned in her own lab. The master cell bank acts like a mold that an auto assembly plant would use to create a fender, allowing the vaccine to be created exactly the same way each time.
Now, when Emens requests more vaccine, the lab can transform a small number of cells into flasks of cells and then into many trays of cells, feeding them regularly with a nutritious substance that allows those many billions of cells to be grown in the matter of a week. None of the process is mechanized.
When completed, the vaccine is stored in a liquid nitrogen freezer until a patient arrives for her shots.
But the vaccine itself is not enough to halt cancer. Something called regulatory T-cells get in the way. They are essentially protecting the tumor from attack, since the body thinks the tumor is just another part of itself, something to be kept free from harm. This is why Emens has given nearly all of the women in her two trials chemotherapy along with the vaccine.
The women in both Emens' first and second trials got a low dose of cyclophosphamide, a chemotherapy agent, the day before they received the vaccine. The cyclophosphamide is meant to knock down the regulatory T-cells so the T-cells can do their work. In the first trial of 28 women, Emens learned that the ideal dose of cyclophosphamide may be quite small, 200 mg/m(+2). Above that, the drug is more likely to kill off the very immune response the vaccine is attempting to achieve.
