Four class 1 molecules are constructed around a fragment of protein from a virus to make a tetramer
A) "It's changed our life."
B) "It's just an assay."
If you answered "both," you're up on your immunology. The tetramer is just an assay, but it's been making immunologists giddy in the last few years. Peter Doherty of St. Jude Children's Research Hospital made the first statement (while acknowledging the second) most recently. He shared the 1996 Nobel Prize for physiology or medicine for his 1970s discovery that T cells must recognize two targets on the surface of a tumor, viral, or graft cell before killing it: the major histocompatibility complex (MHC) molecule and the antigen it cradles. But like all other immunologists, he didn't know his own antigen-specific CD8 "killer" T cells until the tetramer showed...