Distinct roles of cytolytic effector molecules for antigen-restricted killing by CTL in vivo

Edith M. Janssen, Ed E. Lemmens, Naina Gour, Rachel A. Reboulet, Douglas R. Green, Stephen P. Schoenberger, Michael J. Pinkoski

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Cytotoxic T lymphocytes (CTLs) represent one of the front lines of defense for the immune system, killing virus-infected and tumor-transformed cells. CTL use at least two mechanisms to induce apoptosis in their targets, one mediated by perforin and granzymes, and the other triggered by the death ligand, CD95 ligand (CD95L). Here, we used an in vivo cytotoxicity assay to measure specific clearance of antigen-bearing target cells in mice that had previously been immunized with noninfectious cell-associated antigens. We found that perforin was dispensable for efficient clearance of antigen-bearing cells from immunized mice, but only if CD95/CD95L was functional; however, there was a delay in target cell clearance in the absence of perforin. In addition, we observed 35% target cell clearance in the absence of both perforin and CD95L, which was only slightly abrogated in the presence of a neutralizing anti-tumor necrosis factor (TNF) antibody. The presence of a dominant negative Fas-associated death domain (FADD) did not block target cell clearance and therefore cannot be attributed to known death receptors. Taken together, these data suggest that perforin-and CD95L-dependent killing are complementary at early time points, each can compensate for the absence of the other at later time points, and that there is an additional component of antigen-restricted CTL killing independent of perforin, CD95L, and TNFα.

Original languageEnglish (US)
Pages (from-to)761-765
Number of pages5
JournalImmunology and Cell Biology
Issue number7
StatePublished - Oct 2010
Externally publishedYes


  • antigen-restricted killing
  • death receptor/ligand
  • in vivo cytotoxicity
  • perforin

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Cell Biology


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