In April, Yale immunobiologist Ruslan Medzhitov, Ph.D., received one of the highest honors bestowed on American scientists when he was elected to the National Academy of Sciences (NAS), the elite corps of researchers from the nation’s top scientific institutions.

The David W. Wallace Professor of Immunobiology and a Howard Hughes Medical Institute investigator, Medzhitov has done pioneering research on the innate immune system, an evolutionarily ancient physiological system that launches rapid first-line defenses against bacteria and viruses.

“We are all delighted by Ruslan’s election to the NAS, which honors his seminal research on innate immunity,” says Carolyn W. Slayman, Ph.D., Sterling Professor of Genetics and the medical school’s deputy dean for academic and scientific affairs. “Year after year, important new insights keep emerging from his lab.”

As a doctoral student at Moscow State University, Medzhitov was fascinated by a new theory put forth by the late School of Medicine immunobiologist Charles A. Janeway Jr., M.D., which held that the innate immune system somehow provides guidance to the slower, but more fine-tuned responses of the adaptive immune system.

In 1994, Medzhitov came to Yale as a postdoctoral fellow in Janeway’s laboratory, and the two researchers made the groundbreaking discovery that Toll-like receptors (TLRs), a component of the innate system, indeed provide the adaptive system with the necessary information to create custom-made B and T cells that target specific bacterial or viral invaders. Since then, Toll-like receptors have become the subject of intense research activity in laboratories around the world.

“Ruslan’s identification of a Toll-like receptor in mammals and his studies linking innate immune responses with the triggering of specific adaptive immune responses by T cells and B cells have had a huge impact on our understanding of infectious diseases and vaccine development,” says Max D. Cooper, M.D., Georgia Research Alliance Eminent Scholar, professor of pathology and laboratory medicine at Emory University School of Medicine, and NAS member. “The elucidation of TLRs by Ruslan and others has also heightened immunologists’ awareness of the importance of Darwinian evolutionary principles for understanding how the immune system works.”

Last December, Medzhitov was awarded the Lewis S. Rosenstiel Award for Distinguished Work in Basic Medical Science. His election to the NAS brings the number of current Yale faculty who are members to 60. The NAS, a private organization of scientists and engineers dedicated to the furtherance of science and its use for the general welfare, was established in 1863 by a Congressional Act of Incorporation signed by Abraham Lincoln. The Academy acts as an official adviser to the federal government, upon request, in any matter of science or technology.