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Ionizing radiation affects human MART-1 melanoma antigen processing and presentation by dendritic cells
Yu-Pei Liao1, Chun-Chieh Wang, Lisa H Butterfield
1Department of Radiation Oncology, Division of Surgical Oncology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
Journal of Immunology (Baltimore, Md. : 1950)
|August 6, 2004
Summary
Ionizing radiation impacts dendritic cell (DC) antigen presentation differently depending on peptide loading. Radiation impairs endogenous antigen presentation but enhances exogenous antigen presentation, affecting anti-tumor immunity.
Area of Science:
- Immunology
- Radiation Biology
- Cellular Biology
Background:
- Radiation is typically viewed as immunosuppressive due to lymphocyte killing.
- Dendritic cells (DCs) are crucial antigen-presenting cells in immunity.
Purpose of the Study:
- To investigate the non-cytotoxic effects of ionizing radiation on DC antigen presentation.
- To determine how radiation influences MHC class I antigen presentation via endogenous and exogenous pathways.
Main Methods:
- Used adenovirus-transduced murine DCs (AdVMART1) to study endogenous antigen presentation.
- Administered irradiated and non-irradiated DCs to mice to assess T cell responses and anti-tumor immunity.
- Utilized peptide pulsing with MART-1(27-35) and transgenic mice for exogenous pathway analysis.
Main Results:
- Irradiation abrogated T cell responses and anti-tumor immunity mediated by endogenously processed antigens.
- Radiation did not cause DC cytotoxicity, maturation arrest, or loss of MHC class I/costimulatory molecules.
- Irradiation enhanced DC-induced lymphocyte responses to exogenously added peptide fragments.
- Enhanced responses to exogenous peptide conferred protection against tumor growth in transgenic mice.
Conclusions:
- Ionizing radiation non-cytotoxically modulates DC antigen presentation pathways.
- Radiation's effect on MHC class I-mediated immunity is pathway-dependent.
- Radiation can functionally alter DCs, impacting their ability to induce anti-tumor responses.