Ruth Arnon was still asleep when the phone rang at 5:45 a.m.

Michael Sela, her research partner at the Weizmann Institute of Science in Israel, couldn't wait any longer last week to tell her that they'd won the 1998 Wolf Prize in Medicine for creating synthetic vaccines and a multiple sclerosis drug.

"I don't recall Michael's exact words, but I got very excited. I knew I was nominated, but there are dozens of nominees. I didn't have a clue I would get that award," the 64-year-old Arnon said Tuesday from U.C. San Diego, where she's currently on sabbatical.

In the United States since September, Arnon was a featured guest at a San Francisco luncheon on Jan. 28. The event was sponsored by the regional boards of Hadassah and the American Committee for the Weizmann Institute of Science.

Given annually for outstanding achievements in medicine, agriculture, chemistry, mathematics, physics and the arts, the $100,000 prize will be presented to Sela and Arnon at the Knesset on May 10.

The award honors the pair of professors for being the first to introduce synthetic vaccines and developing Copaxone (copolymer-1), a new drug for the treatment of multiple sclerosis.

While Arnon appreciates the necessity of "bringing the achievements of the institute to the general public," she gets the most satisfaction from meeting multiple sclerosis patients who have been aided by Copaxone, the drug whose development began as a basic research project 29 years ago.

Copaxone, which became available in December 1996, slows down the progress of the degenerative disease, which attacks the nervous system. In some cases, Arnon said, the drug "brings some improvement.

"To know my research has brought some good to people on a personal level is exciting," she said.

Arnon delivered a lecture to a Multiple Sclerosis Society forum in Los Angeles last week.

"Quite a few patients came to hear me and talk to me about their own experiences and how they felt," she said of that appearance. "It was very emotional for me."

Winning the award together with Sela, who is deputy chairman of the institute's board and her former professor, was particularly gratifying.

Sela "refers to the period I did my Ph.D. with him [1957-1960] as `when you were in kindergarten,'" she said.

Arnon considers the international prize the highest honor of her career. Although the award was established in Israel, its recipients need not be Israeli. In fact, only six of the 171 previous recipients have been Israeli.

Last year, U.C. San Francisco medical researcher Stanley Prusiner won the Wolf Prize in Medicine. He went on to win a Nobel Prize.

Arnon, who has two grown children and six grandchildren, routinely logged 15-hour days at the institute, dividing her time between the lab and administrative duties as the institute's vice president. "My work is also my hobby," she said.

Research breakthroughs never happen overnight, she said.

"You have to pursue it very stubbornly and be open to many possibilities."