Enhancement of anti-tumor immunity through local modulation of CTLA-4 and GITR by dendritic cells.
Cancer vaccines have now demonstrated clinical efficacy, but immune modulatory mechanisms that prevent autoimmunity limit their effectiveness. Systemic administration of mAbs targeting the immune modulatory receptors CTLA-4 and glucocorticoid-induced TNFR-related protein (GITR) on Treg and effector T cells augments anti-tumor immunity both experimentally and clinically, but can induce life-threatening autoimmunity. We hypothesized that local delivery of anti-CTLA-4 and anti-GITR mAbs to the sites where T cells and tumor antigen-loaded DC vaccines interact would enhance the induction of anti-tumor immunity while avoiding autoimmunity. To achieve this goal, DCs transfected with mRNA encoding the H and L chains of anti-mouse CTLA-4 and GITR mAbs were co-administered with tumor antigen mRNA-transfected DCs. We observed enhanced induction of anti-tumor immunity and significantly improved survival in melanoma-bearing mice, without signs of autoimmunity. Using in vitro assays with human DCs, we demonstrated that DCs transfected with mRNA encoding a humanized anti-CTLA-4 mAb and mRNA encoding a soluble human GITR-L fusion protein enhance the induction of anti-tumor CTLs in response to DCs transfected with mRNAs encoding either melanoma or breast cancer antigens. Based on these results, this approach of using local delivery of immune modulators to enhance vaccine-induced immunity is currently being evaluated in a phase I clinical cancer immunotherapy trial.
Durham VA Medical Center, Durham, NC, USA. scott.pruitt@duke.edu
Scott K
SK
Pruitt
David
D
Boczkowski
Nicole
N
de Rosa
N Rebecca
NR
Haley
Michael A
MA
Morse
Douglas S
DS
Tyler
Jens
J
Dannull
Smita
S
Nair
D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015551:Autoimmunity / Q000276:immunology; D016466:CHO Cells; D060908:CTLA-4 Antigen / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D019496:Cancer Vaccines / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D045744:Cell Line, Tumor; D006224:Cricetinae; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D005260:Female; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008546:Melanoma, Experimental / Q000235:genetics / Q000276:immunology* / Q000378:metabolism / Q000628:therapy; D051379:Mice; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000235:genetics; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism; D014162:Transfection / Q000379:methods; D048069:Tumor Necrosis Factors / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D060908:CTLA-4 Antigen; D019496:Cancer Vaccines; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D012333:RNA, Messenger; C478967:TNFSF18 protein, human; D048069:Tumor Necrosis Factors