title: The immunogenicity of virus-derived 2A sequences in immunocompetent individuals.
abstract: Genetic engineering of T cells for adoptive immunotherapy in cancer patients has shown significant promise. To ensure optimal antitumor activity and safety, the simultaneous expression of multiple genes is frequently required, and short viral-derived 2A sequences are increasingly preferred for this purpose. Concerns exist, however, that these virus-derived sequences may induce unwanted immune responses, and thus diminish persistence of the gene-modified cells after adoptive transfer. Whereas such responses were absent in immunocompromised recipients, potential immunogenicity in immunocompetent individuals remains a concern. We now address whether ex vivo T cell responses can be elicited against the most widely used 2A sequences (2A-Thosea asigna virus (TAV) or 2A-equine rhinitis virus (ERAV), specifically) in immunocompetent individuals. We used a potent ex vivo culture system previously validated to induce T cell responses even against weakly immunogenic antigens. Of the sixteen donors tested, only five released very low levels of interferon-γ in response to 2A-TAV peptide mixtures (single peptide specificity in three donors, adjacent self-antigen peptide specificity in one donor and nonspecific reactivity in one donor). None of them produced cytotoxic activity or responded to 2A-ERAV. These results suggest that exposure to viral-derived 2A sequences is unlikely to produce unwanted T cell responses in immunocompetent individuals and further supports their continued use for studies of human gene therapy.
authors.affiliation: Center for Cell and Gene Therapy, Baylor College of Medicine, The Methodist Hospital and Texas Children's Hospital, Houston, TX 77030, USA.
authors.forename: C
authors.initials: C
authors.lastname: Arber
authors.forename: H
authors.initials: H
authors.lastname: Abhyankar
authors.forename: H E
authors.initials: HE
authors.lastname: Heslop
authors.forename: M K
authors.initials: MK
authors.lastname: Brenner
authors.forename: H
authors.initials: H
authors.lastname: Liu
authors.forename: G
authors.initials: G
authors.lastname: Dotti
authors.forename: B
authors.initials: B
authors.lastname: Savoldo
mesh_terms: D000595:Amino Acid Sequence; D000941:Antigens / Q000276:immunology; D005537:Aphthovirus / Q000235:genetics / Q000276:immunology*; D002460:Cell Line; D005822:Genetic Vectors; D064368:Healthy Volunteers; D006801:Humans; D007121:Immunocompetence; D016219:Immunotherapy, Adoptive; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000276:immunology*; D012328:RNA Viruses / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
chemical_list: D000941:Antigens; D010455:Peptides; D007371:Interferon-gamma