Immune system finding paves way for vaccine use in some leukemia, lymphoma cancers
Researchers at The University of Texas M. D. Anderson Cancer Center and the National Cancer Institute have found that an experimental vaccine can prime the immune system to help fight an aggressive form of lymphoma, even though prior therapy had eliminated virtually all of the B cells thought necessary to mount such a defense.
(I-Newswire) - Their study, published in the September issue of Nature Medicine, has both important basic science and clinical implications, researchers say. It demonstrates that few, if any, B cells are needed to trigger an effective T-cell immune response - a finding which overturns the commonly accepted notion that both are needed to prime the human immune system. The article will be available online on Aug. 21, 2005, at noon CDT.
Their research also tests the use of personalized vaccines to help lymphoma patients fend off a recurrence of their cancer after treatment. Several such cancer vaccines are in human testing. In this study, conducted at the Center for Cancer Research, National Cancer Institute, treatment with a B-cell depleting treatment regimen followed by an experimental vaccine resulted in an impressive 89 percent survival rate at 46 months for 26 patients with mantle cell lymphoma, which is difficult to control. "This is the first human cancer vaccine study to see T-cell responses in the absence of B cells, and this paves the way to use vaccines in a number of hematological cancers that are treated by eliminating diseased B cells," says the study's first author, Sattva Neelapu, M.D., an assistant professor in the Department of Lymphoma at M. D. Anderson.
Those cancers include forms of lymphoma and leukemia in which the cancer evolves in B-cell lymphocytes, white blood cells whose job is to produce antibodies that activate a response by the immune system. New treatments, such as rituximab, are designed to completely wipe out diseased ( as well as healthy ) B cells and can prolong patient survival. However, because researchers were concerned that B-cell depletion from rituximab may impede immune responses to cancer vaccines, and animal studies were contradictory, rituximab has been omitted from lymphoma vaccine studies, according to Wyndham Wilson, M.D., Ph.D., the study's principal investigator and Chief, Lymphoid Malignancies Therapeutic Section, NCI.
This question has now been answered, says senior author Larry Kwak, M.D., Ph.D., professor and chair of the Department of Lymphoma at M. D. Anderson. "We were frankly surprised to find that B cells were coming back in patients that were already primed to fight their tumors," he says. "Now we know B cells are not needed for T-cell immunity."
The study was designed to address the immunological effects of B-cell depletion and to assess the use of idiotype vaccine in mantle cell lymphoma, a rare type of non-Hodgkin's lymphoma for which there is no effective long-term therapy - the majority of patients relapse and succumb to their disease. Kwak helped develop the vaccine while he worked at the National Cancer Institute ( NCI ) before moving to M. D. Anderson. The so-called "idiotype" vaccine is tailored to each patient, based on the specific antigens present on the outside of the diseased B cells. The vaccine is designed to alert a patient's immune system to those antigens, and train it to destroy these cells whenever they appear.
The vaccine was originally tested for use in follicular lymphoma, and was subsequently licensed by the NCI to Accentia Biopharmaceuticals. That company, for which Kwak now consults, is testing it in a Phase III clinical trial. Besides that vaccine, known by the name Biovaxid, two other customized lymphoma vaccines are now being tested in the United States, and each differs only in the way that they are produced.
In this Phase I study, researchers prepared an individualized vaccine for each patient based on the specific antigens present on their cancerous B cells. The vaccine was given to the patients three months after chemotherapy/rituximab treatment, and five doses in all were given at monthly intervals.
"After the third vaccination, we began to see T-cell responses. An antibody response to the tumor produced by recovering B cells was seen after the fourth or fifth vaccination," says Neelapu.
That antibody response was unexpected, researchers say. "We don't know how it happened," Neelapu says. "It may be that some precursor B cells were being primed or that there were very small numbers of B cells remaining in lymph nodes or other compartments that were not depleted. Or other immune cells, such as dendritic cells, may have taken up antigen presenting cell function."
Although several patients have relapsed for reasons that are unclear, "so many of these patients continue to be alive that it is quite possible the vaccine did modify the natural history of the disease," Kwak says. "We can't over interpret this single study, but these patients may have done better than expected."
Typical overall survival for mantle cell lymphoma is 50 percent at three years, Wilson says.
M. D. Anderson researchers are already working on improving the vaccine before testing it further.
Co-authors of the study include, from the NCI: Carol Kobrin, Ph.D.; Craig Reynolds, Ph.D.; John Janik, M.D.; Kieron Dunleavy, M.D.; Therese White; Linda Harvey; Robin Pennington; Maryalice Stetler-Stevenson, M.D., Ph.D.; Elaine Jaffe, M.D.; Seth Steinberg, Ph.D.; Ronald Gress, M.D.; and Fran Hakim, Ph.D.
Jay Edwards jmedward@mdanderson.org 713-792 - 0655 University of Texas M. D. Anderson Cancer Center http://www.mdanderson.org
If you have questions regarding information in this press release contact the company listed below. I-Newswire.com is a press release service and not the author of this press release. The information that is on or available through this site is for informational purposes only and speaks only as of the particular date or dates of that information. As some companies / PR Agencies submit their press releases once per week/month or quarter, make sure check the official company website for accurate release dates as our site displays the I-Newswire.com distribution date only. We do not guarantee the accuracy or completeness of information on or available through this site, and we are not responsible for inaccuracies or omissions in that information or for actions taken in reliance on that information.
Immerse yourself in mystery and magic with two exciting new casual games from Focus Multimedia and Big Fish Games Studios, one of the world’s leading casual game developers. Hidden Expedition Titanic and Azada join Focus’ popular Revival range of super-budget price games and are available in a store near you.
Edraw Max enables students, teachers and business professionals to reliably create and publish kinds of diagrams to represent any ideas. With large pre-drawn libraries and more than 4600 vector symbols, drawing couldn't be easier!
New range of cards launched to make you the cover star.Hallmark Cards in partnership with OK Magazine has launched an exclusive and exciting new range of greeting cards that gives people the chance to give family and friends the A-List treatment.
Many people choose not to pursue an accident claim. The reasons range from knowing the insurance company will settle; to they don't want the legal hassles and expense.
Many individuals and businesses have always purchased their personal computers from a well-known provider to pre-conceived specifications. Increasingly...
The effectiveness of SEO and PPC Services are directly related to the quality and quantity of the performance data that they have to work with. If you are seeking assistance in achieving a higher ranking on search engine results, then we suggest you visit RankYourWebsites.com, specialist in this area. If you have found your attempts at optimization to prove fruitless, the representatives at RankYourWebsites.com will have a solution to increase your traffic.
http://www.vineyardsforsalein.com/ - online island vineyard for sale, vineyard for sale paso, texas vineyard for sale, washington vineyard for sale, tuscany vineyard for sale, vineyard for sale santa, vineyard for sale California
Mark Flanagan, Managing Director of Manchester health and safety, food safety and fire safety consultancy, Shieldyourself, discussed the Scores on the Doors scheme when he made a guest appearance on the BBC’s 5 Live Radio Show recently.
