Tolerance in T-cell clones.

The interaction of antigen with immunologically competent cells may lead either to the induction of an immune response or to a state of antigen specific unresponsiveness complete orpartial, which is often called immunological 'tolerance'. This is believed to be a major mechanism of discrimination between self and non-self(1-3). In this review Marc Feldmann and his colleagues discuss new insights into T-cell tolerance in vivo and in vitro, and discuss their significance for our understanding of mechanisms of immune activation and regulation.