快猫短视频

INSERTING a foreign gene into a patient鈥檚 bone-marrow cells could help their
immune system to accept transplants from non-human donors.

Although drugs can stop the body from rejecting a human transplant, the
immune system won鈥檛 accept animal organs for very long. This is because the
single most common antibody in human blood is directed against the carbohydrate
&agr;Gal, found in the tissues of all non-primate mammals.

But John Iacomini at the Harvard Medical School in Boston and his colleagues
have found a way to persuade antibodies not to attack cells that are making
&agr;Gal. To try the technique in lab animals, they used mice that were genetically
engineered so that, like humans, they lacked the gene that allows &agr;Gal to be
made and instead produced &agr;Gal antibodies.

Then the researchers extracted antibody-producing B cells from bone marrow,
added the aGal gene, and transplanted them back in. These cells produced &agr;Gal,
and the rest of the body saw it as 鈥渟elf鈥�. Antibodies in the mouse serum did not
attack pig kidney cells in a dish (Science, vol 281, p 1845).

Iacomini plans to use engineered marrow to try something like transplanting a
pig鈥檚 organ into a baboon. Other experts in the field are cautiously optimistic.
鈥淚t鈥檚 a very elegant solution,鈥� says Uri Galili, an immunologist at Allegheny
University of the Health Sciences in Philadelphia. 鈥淏ut it鈥檚 really uncharted
waters whether it will work for an actual transplant.鈥�