London, November 3 : A team of researchers from Baylor College of Medicine and Texas Children's Hospital has found that the ability of the immune system cells called T-lymphocytes to fight childhood cancer neuroblastoma can be improved with the aid of an artificial tumour-specific receptor.
"This is a way to convert a naturally occurring problem into a benefit in treating cancer," Nature Medicine quoted Dr. Malcolm Brenner, director of the Center for Cell and Gene Therapy at BCM, TCH and The Methodist Hospital, and professor of pediatrics and medicine at BCM, as saying.
He revealed that his team had used the novel approach in 11 patients with recurring neuroblastoma.
"For the first time, we started to see tumour responses. We have one complete remission and others who have had stable disease for more than a year," he added.
He revealed that the patients responded after only the one infusion of cells because they last a long time in the body and their numbers can increase.
Scientists previously failed to effectively use T-lymphocytes with an artificial receptor directed to tumour cells because they disappeared from the body too quickly to have an anti-cancer effect.
However, cytotoxic T cells that already have a natural receptor for the Epstein-Barr virus are continually activated by the presence of the virus, which is never eliminated from the body.
Brenner revealed that his team added to such T-lymphocytes a particular receptor for a protein called diasialoganglioside GD2, which is found in human neuroblastoma cells.
"We took the T-lymphocytes' with specificity for Epstein-Barr and added another receptor. In effect they trampoline off the virus and onto the tumour," he added.
The researcher said that the virus constantly stimulated cytotoxic T-lymphocytes so that they could remain in the body, and their artificial antigen receptor enabled them to latch onto and kill the cancer cells.
Upon putting the artificial receptor into both ordinary T-lymphocytes and those that are stimulated by the virus into the 11 patients, the researchers observed that the cancer directed cells stimulated by the Epstein-Barr virus lasted as long as 18 months, and at higher levels than the other cells.
Brenner hopes to improve the treatment in future so as to make the T-lymphocytes more potent cancer killers.
Within the next year, he and his colleagues plan to add receptors for other cancers to the virus-specific T-cells, and see whether they get the same cancer-fighting effect.