It is now generally accepted that T cells require two signals for ,, efficient activation: signal 1 is ligation of the T cell ... ligation (signal 1) in the absence of an APC-derived costimulatory signal ,, results in antigen-specific tolerance. Many people ...

Strauss, C., J.H. Mussgnug and O. Kruse (2001). Ligation-mediated suppression-PCR as a powerful tool to analyse nuclear gene ...