title: Fusion of a cell penetrating peptide from HIV-1 TAT to the Theileria parva antigen Tp2 enhances the stimulation of bovine CD8+ T cell responses.
abstract: Immunity to the bovine apicomplexan parasite Theileria parva is associated with MHC-I restricted CD8+ T cell responses directed against the intralymphocytic schizont stage of the parasite. A number of schizont-stage antigens that are targets of CD8+ T cell responses from immune animals have been identified but an effective delivery strategy that consistently induces protective CD8+ T cell responses remains to be developed. This study aimed to determine whether fusing Tat, a cell penetrating peptide (CPP) from HIV-1 TAT, to a CD8+ T cell target antigen from T. parva (Tp2) enhances the cytosolic delivery and subsequent stimulation of bovine CD8+ T cell responses in vitro. Using IFN-gamma ELISpot and cytotoxicity assays, it was demonstrated that recombinant Tat-Tp2 fusion protein possessed a superior ability to access MHC-I processing and presentation pathway and to stimulate CD8+ T cell responses compared to recombinant Tp2 protein. Exposure of APC to Tat-Tp2 protein for only 30 min was sufficient for protein uptake and stimulation of CD8+ T cells. This work describes for the first time the utility of a CPP to enhance MHC-I presentation in a veterinary species and supports the evaluation of CPP fusion proteins in the induction of CD8+ T cell responses in vivo.
authors.affiliation: International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya.
authors.forename: Alex N
authors.initials: AN
authors.lastname: Tinega
authors.forename: Roger
authors.initials: R
authors.lastname: Pellé
authors.forename: Simon
authors.initials: S
authors.lastname: Kang'a
authors.forename: Michael M
authors.initials: MM
authors.lastname: Gicheru
authors.forename: Evans L N
authors.initials: EL
authors.lastname: Taracha
authors.forename: Vishvanath
authors.initials: V
authors.lastname: Nene
authors.forename: Simon P
authors.initials: SP
authors.lastname: Graham
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D002417:Cattle; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000494:pharmacology*; D016797:Theileria parva / Q000276:immunology*; D013801:Theileriasis / Q000188:drug therapy / Q000276:immunology* / Q000469:parasitology; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*
chemical_list: D000953:Antigens, Protozoan; D015395:Histocompatibility Antigens Class I; D011993:Recombinant Fusion Proteins; D054322:tat Gene Products, Human Immunodeficiency Virus; D007371:Interferon-gamma