Dendritic Cells: Developing a Cancer Vaccine

The clinical trial, authored by Hoag Cancer Center Medical Director Robert O. Dillman, M.D., with his team of Ph.D. scientists, tests a new type of cancer vaccine that uses dendritic cells (known as DC’s) and a patient’s own tumor cells. These DC’s essentially govern the body’s immune response, gobbling up cells that are harmful and helping the immune system destroy them.

The key to this trial is to grow purified cells from the patient’s own tumor and feed them directly to a supply of his or her own DC’s. The premise is, the DC’s will identify the cancer cells as harmful to the body and once the vaccine is given to the patient, the immune response against the cancer cells will be set in motion inside the body. But first you need the tumor cells.

Andrew Cornforth, Ph.D. is in charge of purifying and growing tumor cells. The process can begin only if fresh tumor tissue has been surgically removed from the patient and slowly frozen under special conditions (cryopreservation). The cells are put into a culture and incubated under physiologic conditions for up to several months. Cells are inspected daily with frequent changes of a nutrient media that contains carbohydrates, proteins, lipids, growth factors, hormones and vitamins to facilitate tumor cell growth. One of the challenges is the elimination of normal cells called fibroblasts, that sometimes interfere with tumor cell growth. About 65% of melanoma samples eventually can be grown as a cell line, but it takes at least four months half the time, and as long as 11 months.

For the dendritic cell-tumor cell vaccine, once a cell line is established and expanded in numbers, patients undergo a procedure called leukapheresis in which peripheral blood cells called monocytes are collected. These are incubated in another nutrient mixture containing biological molecules that cause some of the cells to convert to dendritic cells (DCs). Dr. Cornforth also oversees this process. Before the tumor cells and DC’s are introduced to one another, the tumor cells are treated with radiation so they cannot reproduce once reintroduced into the body. to create the vaccine which consists of DC’s "loaded" with tumor cells. The vaccine is then injected into the patient’s arm.

Dr. Cornforth agrees by says, “I am continually amazed at the complexity of the human immune system. By providing this type of immunotherapy, Hoag Cancer Center is at the forefront of technology. For me, being part of leading edge work that is unique and fascinating and at the same time a hopeful treatment option for our patients is both personally and professionally fulfilling.”

For more information about Hoag Clinical Trials, click here or call Hoag Cancer Center at 949/7-CANCER (722-6237).