Intracellular tumor-associated antigens represent effective targets for passive immunotherapy.
Monoclonal antibody (mAb) therapy against tumor antigens expressed on the tumor surface is associated with clinical benefit. However, many tumor antigens are intracellular molecules that generally would not be considered suitable targets for mAb therapy. In this study, we provide evidence challenging this view through an investigation of the efficacy of mAb directed against NY-ESO-1, a widely expressed immunogen in human tumors that is expressed intracellularly rather than on the surface of cells. On their own, NY-ESO-1 mAb could neither augment antigen-specific CD8(+) T-cell induction nor cause tumor eradication. To facilitate mAb access to intracellular target molecules, we combined anti-NY-ESO-1 mAb with anticancer drugs to accentuate the release of intracellular NY-ESO-1 from dying tumor cells. Strikingly, combination therapy induced a strong antitumor effect that was accompanied by the development of NY-ESO-1-specific effector/memory CD8(+) T cells that were not elicited by single treatments alone. The combinatorial effect was also associated with upregulation of maturation markers on dendritic cells, consistent with the organization of an effective antitumor T-cell response. Administration of Fc-depleted F(ab) mAb or combination treatment in Fcγ receptor-deficient host mice abolished the therapeutic effect. Together, our findings show that intracellular tumor antigens can be captured by mAbs and engaged in an efficient induction of CD8(+) T-cell responses, greatly expanding the possible use of mAb for passive cancer immunotherapy.
Department of Cancer Vaccine, Cellular and Molecular Immunology, and Immuno-Gene Therapy, Mie University Graduate School of Medicine, Mie, Japan.
Takuro
T
Noguchi
Takuma
T
Kato
Linan
L
Wang
Yuka
Y
Maeda
Hiroaki
H
Ikeda
Eiichi
E
Sato
Alexander
A
Knuth
Sacha
S
Gnjatic
Gerd
G
Ritter
Shimon
S
Sakaguchi
Lloyd J
LJ
Old
Hiroshi
H
Shiku
Hiroyoshi
H
Nishikawa
D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D000936:Antigen-Antibody Complex / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use; D007116:Immunization, Passive; D008565:Membrane Proteins / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009374:Neoplasms, Experimental / Q000276:immunology / Q000628:therapy*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors
D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000951:Antigens, Neoplasm; D005472:Fluorouracil; D008565:Membrane Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; C104948:CTAG1B protein, human