Mechanisms of CTL-mediated cytoxicity

Abstract

Abstract CTL can utilize three separate mechanisms for killing foreign or virally infected cells. The perforin and Fas lytic mechanisms cause rapid (4–6h) lysis of target cells; surface-bound TNF-α causes slow (18–24h) destruction of target cells. In order to assess the relative contributions of the various lytic pathways in immune reactions thought to be based on CMC, several laboratories have generated perforin-less (P0) mice. Although such mice have intact vigorous Fas and TNF-α lytic pathways, they are unable to clear infection by LCMV. On the other hand, they are able to reject allografts. The implications of this for CTL function in vivo are discussed.