Enzyme ruse successful
A method of protecting a therapeutic enzyme from destructionby the immune system has proven "remarkably successful,' says Rebecca H. Buckley of Duke University in Durham, N.C. She and her colleagues used the treatment earlier this year (SN: 5/3/86, p.277) to supply the enzyme, adenosine deaminase (ADA), to two children with severe combined immunodeficiency.
The children had been born without the ability to producetheir own ADA. Without ADA, the immune system can't function normally, but it can still destroy foreign ADA.
Buckley and her colleagues used ADA molecules studdedwith polyethylene glycol (PEG), the main ingredient in antifreeze. The PEG shielded the enzyme from immune system cells, but the smaller molecules on which the enzyme normally acts were able to diffuse through the PEG barrier. The ADA brought back immune function where there had been none, Buckley reported at the meeting and in the March 5 NEW ENGLAND JOURNAL OF MEDICINE.
The only other treatment for ADA deficiency is bone marrowtransplantation, for which a matched donor is needed and which is effective in only half the cases treated. The antifreeze protection may work in other enzyme deficiencies as well, Buckley says.
COPYRIGHT 1987 Science Service, Inc.
COPYRIGHT 2004 Gale Group
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