Immunotherapy with dendritic cells pulsed with tumor-derived gp96 against murine lung cancer is effective through immune response of CD8+ cytotoxic T lymphocytes and natural killer cells.
OBJECTIVE
Immunization with heat shock proteins, gp96, elicits specific protective immunity against parent tumors. However, it is marginally effective as a therapeutic tool against established tumors. In the present study, we evaluated the efficacy and mechanism of immunotherapy with bone marrow-derived dendritic cells (DCs) pulsed with tumor-derived gp96 against murine lung cancer.


METHODS
Mice were transplanted subcutaneously with ovalbumin (OVA)-transfected Lewis Lung Cancer (LLC-OVA) cells and immunized with gp96 derived from LLC-OVA, DCs, or DCs pulsed with gp96 derived from LLC-OVA.


RESULTS
The antitumor effect was significantly enhanced in the mice immunized with DCs pulsed with gp96 derived from LLC-OVA, compared to mice immunized with gp96 or DCs (P<0.05). The antitumor effect was significantly dependent on natural killer (NK) cells and CD8(+) cells and partially dependent on CD4(+) cells. Analysis by laser confocal microscopy demonstrated that gp96 was shown on the cell surface at 15 min, and after 30 min internalized in the endosomes and not in the endoplasmic reticulum or lysosomes. OVA-specific(+) CD8(+) cells were more readily recruited into the draining lymph nodes and higher CD8(+) cytotoxic T cell activity against LLC-OVA was observed in splenocytes from mice immunized with DCs pulsed with gp96 derived from LLC-OVA. Re-challenge of the surviving mice with LLC-OVA tumors after the initial tumor inoculation showed dramatic retardation in tumor growth.


CONCLUSIONS
In conclusion, immunotherapy of DCs pulsed with tumor-derived gp96 against murine lung cancer is effective through immune response of CD8(+) cytotoxic T lymphocytes and NK cells.
Shinagawa
Naofumi
N
First Department of Medicine, Hokkaido University School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.
Yamazaki
Koichi
K
Tamura
Yasuaki
Y
Imai
Akihito
A
Kikuchi
Eiki
E
Yokouchi
Hiroshi
H
Hommura
Fumihiro
F
Oizumi
Satoshi
S
Nishimura
Masaharu
M
D000818:Animals; D000951:Antigens, Neoplasm / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D018827:Carcinoma, Lewis Lung / Q000628:therapy; D003713:Dendritic Cells / Q000276:immunology / Q000637:transplantation*; D005260:Female; D016219:Immunotherapy, Adoptive / Q000379:methods*; D007694:Killer Cells, Natural / Q000276:immunology*; D008175:Lung Neoplasms / Q000628:therapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal
D000951:Antigens, Neoplasm; C052646:sarcoma glycoprotein gp96 rejection antigens