CD8+ T cells circumvent immune privilege in the eye and mediate intraocular tumor rejection by a TNF-alpha-dependent mechanism

J Immunol. 2007 May 15;178(10):6115-22. doi: 10.4049/jimmunol.178.10.6115.

Abstract

Although intraocular tumors reside in an immune-privileged environment, T cells can circumvent immune privilege and mediate tumor rejection without inducing damage to normal ocular tissue. In this study, we used a well-characterized tumor, Ad5E1 (adenovirus type 5 early region 1), to analyze the role of CD8+ T cells in the pristine rejection of intraocular tumors. It has been previously documented that Ad5E1 tumor rejection can occur in the absence of CD8+ T cells. However, here we find that CD8+ T cells infiltrated intraocular Ad5E1 tumors in C57BL/6 mice. Surprisingly, CD8+ T cells from tumor-rejector mice could mediate intraocular tumor rejection following adoptive transfer to SCID mice. In determining the mechanisms behind CD8+ T cell-mediated tumor rejection, we discovered that antitumor CTL activity was neither observed nor necessary for rejection of the intraocular tumors. CD8+ T cells from rejector mice did not produce IFN-gamma in response to Ad5E1 tumor Ags or use FasL to mediate intraocular tumor rejection. Also, CD8+ T cells did not use perforin or TRAIL, as CD8+ T cells from perforin knockout (KO) and TRAIL KO mice conferred protection to SCID recipient mice following adoptive transfer. We discovered that CD8+ T cells used TNF-alpha to mediate tumor rejection, because Ad5E1 tumor cells were highly sensitive to TNF-alpha-induced apoptosis and CD8+ T cells from TNF-alpha KO mice did not protect SCID mice from progressive Ad5E1 tumor growth. The results indicate that CD8+ T cells circumvent immune privilege and mediate intraocular tumor rejection by a TNF-alpha-dependent manner while leaving the eye intact and vision preserved.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviruses, Human / immunology
  • Animals
  • Anterior Chamber / immunology*
  • Anterior Chamber / pathology
  • Anterior Chamber / virology*
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / metabolism*
  • CD8-Positive T-Lymphocytes / pathology
  • Cell Line, Tumor
  • Cell Movement / immunology
  • Eye Neoplasms / immunology*
  • Eye Neoplasms / pathology
  • Eye Neoplasms / prevention & control*
  • Eye Neoplasms / virology
  • Graft Rejection / genetics
  • Graft Rejection / immunology*
  • Graft Rejection / pathology
  • Graft Rejection / virology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred DBA
  • Mice, Knockout
  • Mice, SCID
  • Neoplasm Transplantation / immunology
  • Sarcoma, Experimental / immunology
  • Sarcoma, Experimental / pathology
  • Sarcoma, Experimental / prevention & control
  • Tumor Necrosis Factor-alpha / deficiency
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / physiology*

Substances

  • Tumor Necrosis Factor-alpha