Lymph node-targeted immunotherapy mediates potent immunity resulting in regression of isolated or metastatic human papillomavirus-transformed tumors.
OBJECTIVE
The goal of this study was to investigate the therapeutic potential of a novel immunotherapy strategy resulting in immunity to localized or metastatic human papillomavirus 16-transformed murine tumors.


METHODS
Animals bearing E7-expressing tumors were coimmunized by lymph node injection with E7 49-57 antigen and TLR3-ligand (synthetic dsRNA). Immune responses were measured by flow cytometry and antitumor efficacy was evaluated by tumor size and survival. In situ cytotoxicity assays and identification of tumor-infiltrating lymphocytes and T regulatory cells were used to assess the mechanisms of treatment resistance in bulky disease. Chemotherapy with cyclophosphamide was explored to augment immunotherapy in late-stage disease.


RESULTS
In therapeutic and prophylactic settings, immunization resulted in a considerable expansion of E7 49-57 antigen-specific T lymphocytes in the range of 1/10 CD8(+) T cells. The resulting immunity was effective in suppressing disease progression and mortality in a pulmonary metastatic disease model. Therapeutic immunization resulted in control of isolated tumors up to a certain volume, and correlated with antitumor immune responses measured in blood. In situ analysis showed that within bulky tumors, T-cell function was affected by negative regulatory mechanisms linked to an increase in T regulatory cells and could be overcome by cyclophosphamide treatment in conjunction with immunization.


CONCLUSIONS
This study highlights a novel cancer immunotherapy platform with potential for translatability to the clinic and suggests its potential usefulness for controlling metastatic disease, solid tumors of limited size, or larger tumors when combined with cytotoxic agents that reduce the number of tumor-infiltrating T regulatory cells.
Department of Research and Development, MannKind Corporation, Valencia, California, USA.
Kent A
KA
Smith
Brenna L
BL
Meisenburg
Victor L
VL
Tam
Robb R
RR
Pagarigan
Raymond
R
Wong
Diljeet K
DK
Joea
Liz
L
Lantzy
Mayra A
MA
Carrillo
Todd M
TM
Gross
Uriel M
UM
Malyankar
Chih-Sheng
CS
Chiang
Diane M
DM
Da Silva
Thomas M
TM
Kündig
W Martin
WM
Kast
Zhiyong
Z
Qiu
Adrian
A
Bot
D000818:Animals; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000276:immunology / Q000627:therapeutic use; D002472:Cell Transformation, Viral / Q000276:immunology; D003131:Combined Modality Therapy; D003603:Cytotoxins / Q000008:administration & dosage; D005260:Female; D052162:Human papillomavirus 16 / Q000276:immunology / Q000502:physiology*; D006801:Humans; D007111:Immunity, Cellular / Q000502:physiology*; D007167:Immunotherapy / Q000379:methods*; D008198:Lymph Nodes / Q000276:immunology*; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000276:immunology / Q000473:pathology* / Q000517:prevention & control / Q000628:therapy*; D050725:Papillomavirus E7 Proteins / Q000378:metabolism; D047368:Tumor Burden / Q000276:immunology
D019496:Cancer Vaccines; D003603:Cytotoxins; D050725:Papillomavirus E7 Proteins