Alain Townsend is a cellular and molecular biologist whose work on influenza paved the way for contemporary understanding of the immune system response to viral infection. He discovered that infected cells harness and present a viral molecule on their surface, revealing the invader to killer immune cells.
As a young medic, Alain was intrigued by efforts to understand how cytotoxic T lymphocytes (CTL; also known as cytotoxic T cells) — a component of the immune system — destroy virus-infected cells. Turning his career to the lab bench, he discovered that the CTL response is launched when an infected cell exposes a small fragment of a specific influenza protein on its surface.
He showed that viruses are degraded inside infected cells, and that the key protein fragment is associated with major histocompatibility complex (MHC) molecules for presentation. He won the 2000 Canada Gairdner International Award, and has applied his insight into the molecular mechanisms of influenza to the field of vaccine development.