SARS Therapy Via Antibodies
Shows Promise in Research
By MARILYN CHASE
Staff Reporter of THE WALL STREET JOURNAL
Researchers reported progress toward creating a therapy using natural antibodies to fight the deadly SARS virus.
A team of scientists at the Massachusetts Biologic Laboratories of the University of Massachusetts Medical School and Medarex Inc. said their lab-made antibodies quashed in the test tube the virus that causes severe acute respiratory syndrome. If all goes well, the team's leader, Donna Ambrosino, director of Massachusetts Biologic Laboratories, said researchers could have an antibody to test in people as early as next year, and an experimental therapy for the disease within two years.
Despite a flurry of research, there is as yet no proven treatment for SARS, a highly contagious respiratory ailment caused by a newly discovered coronavirus. SARS leaped onto the public health stage late last year, spreading mainly in Asia and Toronto. SARS, marked by "atypical" pneumonia, sickened about 8,100 and killed 774 people world-wide. While the spread of SARS petered out in the spring, public-health officials are worried it could easily resurface in winter, as influenza does.
The goal of the Massachusetts researchers is the creation of a so-called monoclonal antibody, an antibody specially targeted to block the outer "spike protein" of SARS. This spike protein, which gives the SARS coronavirus its crown shape and its name, lets the virus latch onto and enter human cells.
Such precisely targeted antibodies -- a goal of researchers for decades -- now are made by several biopharmaceutical companies to treat an array of diseases, including tumors such as breast cancer and lymphoma, inflammatory conditions such as rheumatoid arthritis and Crohn's disease, and a lung infection that attacks premature infants. Massachusetts Biologic, of Jamaica Plain, Mass., and Medarex, of Princeton, N.J., are currently working on antibodies to fight more infectious diseases.
Dr. Ambrosino said that making this monoclonal antibody is a long and complicated process. First the team used the genetic code of the virus to make the SARS spike protein. Next they injected the spike protein into mice whose immune systems had been engineered to resemble the human immune system. Those mice are designed to react to the SARS spike protein by producing "human" antibodies against it.
In research results presented at the Infectious Disease Society of America meeting in San Diego, the team said that antibody-rich serum from the mice neutralized live SARS virus in the test tube, blocking the virus from infecting new cells. The next step is to isolate the individual cell from the mouse that produces the precise neutralizing antibody to the SARS virus that achieved that result, she said.
"You have to look at thousands and thousands," said Dr. Ambrosino. "It's now a hunting expedition." |
