title: Listeria-derived ActA is an effective adjuvant for primary and metastatic tumor immunotherapy.
abstract: Tumor immunotherapy is currently at the cusp of becoming an important aspect of comprehensive cancer treatment in the clinic. However, the need for improved adjuvants to augment immune responses against tumor antigens is always present. In this paper, we characterize the Listeria monocytogenes-derived actin-nucleating protein, ActA, as a novel adjuvant for use in tumor immunotherapy. ActA is a virulence factor that is expressed on the cell surface of L. monocytogenes and facilitates the production of actin tails that propel Listeria throughout the cytosol of an infected host cell. It is believed that this ActA-dependent cytosolic motility allows Listeria to evade adaptive host cell defenses and facilitates its invasion into a proximal uninfected host cell. However, there is evidence that ActA fused to a tumor antigen and delivered by L. monocytogenes can perform a beneficial function in tumor immunotherapy as an adjuvant. Our investigation of this adjuvant activity demonstrates that ActA, either fused to or administered as a mixture with a tumor antigen, can augment anti-tumor immune responses, break immune tolerance and facilitate tumor eradication, which suggests that ActA is not only an effective adjuvant in tumor immunotherapy but can also be applied in a number of therapeutic settings.
authors.affiliation: University of Pennsylvania, Department of Microbiology, 323 Johnson Pavilion, Philadelphia, PA 19104.
authors.forename: Laurence M
authors.initials: LM
authors.lastname: Wood
authors.affiliation: University of Pennsylvania, Department of Microbiology, 323 Johnson Pavilion, Philadelphia, PA 19104.
authors.forename: Zhen-Kun
authors.initials: ZK
authors.lastname: Pan
authors.affiliation: Advaxis Inc., The Technology Centre of New Jersey, Suite 117, 675 U.S. Route 1, North Brunswick, NJ 08902.
authors.forename: Vafa
authors.initials: V
authors.lastname: Shahabi
authors.affiliation: University of Pennsylvania, Department of Microbiology, 323 Johnson Pavilion, Philadelphia, PA 19104.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Paterson
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000818:Animals; D000951:Antigens, Neoplasm / Q000276:immunology; D001426:Bacterial Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000276:immunology; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D008297:Male; D008565:Membrane Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009362:Neoplasm Metastasis; D009374:Neoplasms, Experimental / Q000276:immunology* / Q000473:pathology / Q000628:therapy*; D050725:Papillomavirus E7 Proteins / Q000235:genetics / Q000276:immunology; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D000276:Adjuvants, Immunologic; D000951:Antigens, Neoplasm; D001426:Bacterial Proteins; D019496:Cancer Vaccines; D008565:Membrane Proteins; D050725:Papillomavirus E7 Proteins; C059731:oncogene protein E7, Human papillomavirus type 16; C072980:actA protein, Listeria monocytogenes