Monoclonal antibodies can be used as potent immune weapons against cancer

March 22nd, 2009 - 11:44 am ICT by ANI  

London, March 22 (ANI): A researcher at Georgetown University Medical Center’’s Lombardi Comprehensive Cancer Center says that monoclonal antibodies can be used as potent immune weapons against cancer.
Louis Weiner, director of the cancer centre at GUMC, says that monoclonal antibody therapy of cancer can be improved to be much more powerful than it is today with modifications.
“We believe that antibody therapy has the capacity to immunize people against cancer. Treatment modifications might be able to prolong, amplify, and shape a continuous immune response to cancer cells,” says Weiner.
Reviewing the last eight years of research on monoclonal antibody treatment, Weiner came to the conclusion that a new era in use of these therapies is just around the corner.
“Scientists have been able to use new tools to measure effectiveness of these therapies, and have found that antibodies are capable of stimulating the immune system in ways that had not been appreciated to date, and which we can now take advantage of,” says the researcher.
Monoclonal antibodies are proteins crafted in a laboratory to recognize specific receptors on cancer cells that promote uncontrolled growth. They are designed to both attach to cancer receptors to inhibit their function, and to alert and activate the immune system to the presence of these receptor proteins.
Monoclonal antibodies already offer effective treatment for a wide range of cancers, including breast cancer, colorectal cancer, lung cancer, and blood cancers.
However, says Weiner, they have appeared to primarily work by forcing tumour related receptors to shut down pro-growth signals.
“For years it has been presumed that the ability of antibodies to interfere with malignant cell-related signalling is the dominant mechanism of anticancer activity, but we have also known that the normal job of an antibody is to deliver an antigen to the body’’s immune system which then destroys the target,” Weiner says.
The current study, however, shows that antibodies can inhibit function not only as signalling manipulators, but also as initiators of immune responses that leads to control of cancer.
“We believe that Herceptin and Rituxan, as examples, work in part by immunizing people against cancer, but at this point, the magnitude of that response is variable and is frequently very small,” Weiner says.
He believes that it may be possible to alter the antibodies so that they induce both kinds of human immunity - the innate immune response that is short-lasting and which directly kills tumour cells, and a long-lasting “memory” response that comes from the adaptive immune response.
“We have long thought that monoclonal antibodies are capable of stimulating the innate immune system, but we now have evidence that the therapy can prime an adaptive response as well. Such responses would make the treatment much more powerful, capable of keeping cancer under control,” he says.
“For the first time we are using technology that can measure the immune response that is occurring in monoclonal antibody treatment, and which will help us build better antibodies that amplify and shape that immune response to become more powerful,” he adds.
He even believes that it may be possible in the near future to develop antibodies that are targeted to existing targets on a patient’’s tumour, as well as to targets that may appear as the cancer mutates.
“This one-two punch would anticipate how the tumour changes over time and cut off the cancer’’s escape route. These new directions are very exciting,” Weiner says.
A report on this study has been published in the journal The Lancet. (ANI)

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