For years, laboratory mice have served well as substitutes for humans in studying diseases or testing new drugs or vaccines. But in many areas, mice have not always proved up to the job of acting as surrogate humans -- in studies of the dauntingly complex and specific human immune system, for example, and in research into how the deadly AIDS virus works to cripple the body's defenses. Last week, however, mice and men suddenly seemed more alike than different, at least in some critical aspects of biology.
In a pair of remarkable studies, one reported in the journal Nature and the...