Before revision:  We model cross-reactive cellular adaptive immune responses induced by multiple infections, and show how the formation and re-activation of memory T cells explains observed shortening of a second infection when cross-reactivity is present . We include three possible mechanisms which determine the strength of the cross-reactive immune response . Our model of cross-reactivity contributes to understanding how repeated exposures change an individual's immune profile over a lifetime .
After revision:  We model cross-reactive cellular adaptive immune responses induced by multiple infections, and show how the formation and re-activation of memory T cells explains observed shortening of a second infection when cross-reactivity is present , and shows that memory in the cellular adaptive immune response is necessary to protect against a second infection .