Researchers from Stanford University and Genentech Inc.reported this week on a technology to prevent T cells fromattacking transplanted organs.
Scientists led by Randall Morris, director of Stanford's KovitzLaboratory for Transplantation Immunology, used an antibodyto block adhesion molecules on T cells. That would prevent theT cells from attaching to transplanted organs and initiating thecascade of events leading to organ rejection.Results of tests in which the heart tissue of white mice wasgrafted onto the ears of brown mice were reported at theannual meeting of the American Society of TransplantPhysicians in Chicago.
In 10 mice given maximum doses of cyclosporine, the standarddrug to prevent rejection, the grafts survived for no more than40 days, Morris told BioWorld. In a second control group thatwas given an antibody that didn't react with immune cells, theheart tissue was rejected in 10 days.
In a group of four mice given the active antibody, the hearttissue survived beyond 160 days in three mice and wasrejected on day 21 in one animal.
Most interesting, said Morris, was the fact that the tissuewasn't rejected in mice treated with the antibody even aftertreatment was stopped. To see if the immune systems of thebrown mice had been damaged by the therapy, heart tissuefrom a strain of black mice was implanted. But that tissue wasrejected, showing that the antibody had created an immunesystem that was selectively tolerant only of the originaltransplant.
The next steps, said Morris, are to understand why thetreatment works and to test it in primates. Those trials beganlast week using an antibody that is known to work in humans.-- Karen Bernstein
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