The research center Applied Medicine (CIMA) of the University of Navarra hosted the "International Symposium on CTL and Immunostimulation", in which experts from different countries discussed aspects of the immune response, in order to better understand the biological processes that lead to the activation of the antiviral and antitumor functions of cytotoxic T lymphocytes (CTLs).

CTLs are essential leukocytes for the protection of the body against viral infections and tumor development . Understanding their defense mechanisms has led to new strategies for the treatment of cancer and chronic viral diseases.

Dr. Carl June of the University of Pennsylvania, USA, presented encouraging results from immunotherapy-based clinical trials for cancer treatment. "One of the main limitations of cancer immunotherapy is innate tolerance to self antigens. By modifying Genetics the patient's lymphocytes, we have managed to break this tolerance and fight tumors," explains June. Her strategy is based on the transfer of CTLs genetically modified to express chimeric receptors, which are capable of recognizing tumor antigens very effectively and killing the transformed cells.

Effective assays against leukemia

Dr. Carl June's group currently has a clinical essay underway with leukemia patients who have not responded to chemotherapy. The treatment consists of removing patients' CTLs, genetically modifying them in vitro to express tumor cell-specific receptors and transfusing them back into the body.

The essay not only sample to what extent CTLs are able to kill tumor cells but also their ability to multiply and survive over time in the body. "We have introduced crucial protein fragments to ensure the survival of transfected CTLs to increase their antitumor capacity," June explains. This clinical essay is in phase 1 and 3 patients have already been treated with positive results. Definitive data is expected to be available in about a year. "The interesting thing about this new treatment for leukemia is that there would be no need to look for a compatible donor, but the patient could be cured with his or her own cells," explains June.

The symposium, attended by about 150 people, was organized by Drs. Sandra Hervás, Pablo Sarobe, and Ignacio Melero, from the area of Gene Therapy and Hepatology at CIMA, at partnership with Alan Melcher, from the Leeds Institute of Molecular Medicine, University of Leeds, UK and sponsored by Miltenyi Biotech. "In this framework for exchange of ideas, success is measured by the joint projects they lead to. The outlook is positive, since the CIMA has launched partnership projects to carry out clinical trials with centers in the USA, Germany and the UK and with the outstanding participation of hospitals in Navarra", says Dr. Melero.