(Free Press News Services: April 22, 1997)

AIDS researchers have reached a milestone in the long and frustrating search for a vaccine against the human immunodeficiency virus.

In a few weeks, 20 men and 10 women in New England will get the first doses of two experimental vaccines against HIV as part of a national 500-person trial to determine their safety.

"We see this as a dry run for a later study to determine efficacy of these vaccines," said a study leader, Dr. kenneth Mayer of Fenway Community Health Center and Brown University.

If the vaccines produce no serious side effects, and if they show promising evidence of immune responses against HIV, the study will lead to a large-scale trial involving 5,000 or more people sometime in the next five years, Mayer said.

A vaccine developed by the French firm Psteur Merieux Connaught consists of a canarypox virus genetically engineered to carry genes for two HIV proteins.

(Canarypox cannot infect humans, nor reproduce itself when injected into humans.) s

That vaccine is intended to stimulate cellular immunity - reactions against cells that have been infected with a virus.

The other vaccine, made by two companies called Chiron and Biocene, is a piece of HIV's outer coat called gp-120. It is supposed to stimulate antibodies against HIV.