Dendritic cell maturation induced by delivery of ultraviolet-mediated apoptotic colorectal cancer cell lines.
BACKGROUND
Dendritic cells (DCs) play a critical role in the immune response. The aim of this study was to investigate apoptotic tumor cells as an antigen source for DC maturation.


METHODS
We compared the efficacy of ultraviolet (UV)-irradiation with that of gamma-irradiation in the induction of apoptosis of tumor cells. Phenotypic and functional changes of DCs were analyzed after co-incubation with UV-irradiated tumor cells.


RESULTS
UV-irradiation (1.8 J/cm2) was a more reliable method of inducing apoptosis than gamma-irradiation (20,000 rad). The expression of costimulatory molecules on DCs was upregulated after co-incubation with UV-irradiated tumor cells. When we performed allogeneic mixed lymphocyte reaction assay, UV-irradiated tumor cells-pulsed DCs stimulated allogeneic T lymphocytes more efficiently than DCs pulsed with gamma-irradiated cells (HT29, p = 0.0419 and WiDr, p = 0.0076).


CONCLUSIONS
UV-irradiation reliably induces apoptosis in cultured colorectal cancer cells. DCs mature in function and expression of costimulatory molecules after co-incubation with apoptotic tumor cells. The clinical implications warrant further study.
Ishii
Shigeaki
S
Second Department of Internal Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8666, Japan.
Hiroishi
Kazumasa
K
Eguchi
Jun-Ichi
J
Mitamura
Keiji
K
D015703:Antigens, CD / Q000096:biosynthesis / Q000276:immunology; D017209:Apoptosis / Q000528:radiation effects; D018122:B7-1 Antigen / Q000096:biosynthesis / Q000276:immunology; D051940:B7-2 Antigen; D002450:Cell Communication / Q000276:immunology; D015179:Colorectal Neoplasms / Q000276:immunology* / Q000473:pathology; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D019073:HT29 Cells; D006801:Humans; D007959:Lymphocyte Culture Test, Mixed; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000276:immunology; D014407:Tumor Cells, Cultured; D014466:Ultraviolet Rays; D015854:Up-Regulation
D015703:Antigens, CD; D018122:B7-1 Antigen; D051940:B7-2 Antigen; C497964:CD86 protein, human; D008562:Membrane Glycoproteins