Promising Immunotherapy Technique

I n a study in the March 2012 Nature Medicine, researchers described a new immunotherapeutic technique that can " teach " immune system killer cells, known as CD8 T cells, and their antigen-presenting instructor cells, to destroy cancer cells. Just as important, the newly trained cells remain vigilant in case the cancer returns. coauthor of the study, " These findings may be useful in T cell–based vaccine design and adoptive T-cell therapy, where potent effec-tor and memory formation are vital for successful eradication of acute and recurrent disease. " Although the immune system can eliminate some cancerous cells, it does not always recognize them as " foreign. " Also, cancer may develop when the immune system breaks down or does not function adequately. Researchers are developing immunotherapeu-tic techniques to repair, stimulate, or enhance the immune system's responses to cancer and other debilitating diseases. G u e v a r a-P a t i n o said that in addition to getting instructions from the antigen-presenting cells, CD8 T cells need assistance from helper T cells to become effective killers. Under " normal " conditions, DNA directs helper T cells to overproduce a specific protein that unleashes the killer T cells' lethal properties. However, these cells are typically repressed in patients with cancer or HIV. Especially in cancer patients, one of a tumor's menacing properties is its ability to prevent killer T cells from eliminating tumors by putting helper T cells into a suppressed stage, limiting their ability to assist CD8 T cells. According to the researchers, this new technique jump-started defective immune systems in immunocompromised mice and in human killer T cells taken from HIV patients. Guevara-Patino said a clinical trial in cancer patients could begin in about 3 years. In the study, a device called a gene gun delivered snippets of DNA into skin instructor cells. The DNA directed the instructor cells to produce specific proteins, which act like molecular keys. When CD8 T cells interact with the instructor cells, the keys unlock the CD8 T cells' killer properties , jump-starting them to seek out and kill pathogens and cancer cells. With this technique , the killer T cells would not need helper T cells, said G u e v a r a-P a t i n o. So even if a tumor were to suppress the helper T cells, the killer T cells could still kill cancer cells. …