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Updated: Sep 26, 2026

Real Time Detection of In Vitro Tumor Cell Apoptosis Induced by CD8+ T Cells to Study Immune Suppressive Functions of Tumor-infiltrating Myeloid Cells
09:57

Real Time Detection of In Vitro Tumor Cell Apoptosis Induced by CD8+ T Cells to Study Immune Suppressive Functions of Tumor-infiltrating Myeloid Cells

Published on: January 29, 2019

Identification of a tumor-associated contact-dependent activity which reversibly downregulates cytolytic function of

D L Levey1, H Udono, M Heike

  • 1Center for Immunotherapy of Cancer and Infectious Diseases, Mail Code 1601, University of Connecticut School of Medicine, Farmington, CT 06030, USA.

Cancer Immunity
|May 16, 2003
PubMed

Insights

Tumors can suppress the immune system by downregulating CD8+ T cell activity. This contact-dependent mechanism, observed in various tumors, explains local immune evasion despite systemic immune health.

Area of Science:

  • Immunology
  • Oncology
  • Cell Biology

Background:

  • Tumors paradoxically grow despite host immune responses.
  • Tumor cells may express factors that inhibit immune cells.
  • Systemic immunosuppression is rare in tumor-bearing hosts.

Purpose of the Study:

  • To investigate tumor-induced suppression of CD8+ T cell activity.
  • To determine if this suppression is a general tumor characteristic.
  • To elucidate the mechanism of immune evasion within the tumor microenvironment.

Main Methods:

  • Utilized methylcholanthrene-induced fibrosarcoma (Meth A) model.
  • Assessed CD8+ T cell lytic activity in the presence of various tumors.
  • Investigated the contact-dependent and reversible nature of the suppressive activity.

Main Results:

  • Meth A and other tumors demonstrated the ability to downregulate CD8+ T cell lytic activity.
  • The suppressive effect was confirmed to be contact-dependent.
  • The observed immune suppression was reversible.

Conclusions:

  • Local tumor microenvironment events can subvert specific anti-tumor immune responses.
  • Tumor-induced downregulation of CD8+ T cell activity is a key immune evasion strategy.
  • Findings provide insight into tumor progression despite host immunity.

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