Peter C. Doherty
Australian immunologist and pathologist who, with Rolf Zinkernagel of
Switzerland, received the Nobel Prize for Physiology or Medicine in
1996 for their discovery of how the body's immune system distinguishes
virus-infected cells from normal cells.
Doherty earned bachelor's (1962) and master's (1966) degrees in veterinary
medicine from the University of Queensland but switched to pathology
while earning his doctorate (1970) from the University of Edinburgh,
Scot. While conducting research (1972-75) at the John Curtin School
of Medical Research in Canberra, Doherty began collaborating with Zinkernagel
in studying what role the white blood cells known as T lymphocytes (T
cells) play in mice infected with a particular type of virus able to
cause meningitis. They theorized that it was the strength of the immune
response itself that caused the fatal destruction of brain cells in
mice infected with this virus. To test this theory, they mixed virus-infected
mouse cells with T lymphocytes from other infected mice. The T lymphocytes
did destroy the virus-infected cells, but only if the infected cells
and the lymphocytes came from a genetically identical strain of mice;
the T lymphocytes would ignore virus-infected cells that had been taken
from another strain of mice. Further research owed that T cells must
recognize two separate signals on an infected cell before they will
destroy it. One signal is a fragment of the invading virus that the
cell displays on its surface; the other is a self-identifying tag from
the cell's major histocompatibility complex (MHC) antigens, which identify
a cell as belonging to one's own body. This concept of the simultaneous
recognition of both self and foreign molecules formed the basis for
a new understanding of the general mechanisms used by the immune system
at the cellular level.
After teaching at the Wistar Institute in Philadelphia, Pa. (1975-82),
Doherty headed the department of pathology at the Curtin School in Canberra
(1982-88) and became chairman of the department of immunology at St.
Jude Children's Research Hospital in Memphis, Tenn., in 1988.