title: Plasmodium yoelii: peptide immunization induces protective CD4+ T cells against a previously unrecognized cryptic epitope of the circumsporozoite protein.
abstract: In this study we characterized the CD4+ T cell response directed against two distinct epitopes located in the circumsporozoite (CS) protein of Plasmodium yoelii. The immunization of mice with P. yoelii sporozoites induced CD4+ T cells which were mostly directed against one of these peptides, Py-1, previously reported to contain a CD4+ epitope. The CD4+ T cells directed against this immunodominant epitope were mostly of the Th-1 type. Another newly identified peptide, AS44, induced a specific CD4+ T cell response, which was mainly detectable after immunization with the corresponding peptide. Several CD4+ T cell clones, recognizing this epitope, were generated and their lymphokine expression was characterized, as well as their surface markers and their anti-parasite activity in vivo. It was noteworthy that some of these CD4+ T cell clones, which recognize this cryptic epitope and were of different Th subtypes, were shown to have a strong inhibitory effect on the development of liver stages of malaria parasites.
authors.affiliation: Department of Medical and Molecular Parasitology, New York University School of Medicine, New York 10010, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Takita-Sonoda
authors.forename: M
authors.initials: M
authors.lastname: Tsuji
authors.forename: K
authors.initials: K
authors.lastname: Kamboj
authors.forename: R S
authors.initials: RS
authors.lastname: Nussenzweig
authors.forename: P
authors.initials: P
authors.lastname: Clavijo
authors.forename: F
authors.initials: F
authors.lastname: Zavala
mesh_terms: D019264:Adoptive Transfer; D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D007114:Immunization; D016056:Immunodominant Epitopes; D007371:Interferon-gamma / Q000378:metabolism; D015848:Interleukin-5 / Q000378:metabolism; D008288:Malaria / Q000276:immunology* / Q000469:parasitology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010455:Peptides / Q000276:immunology*; D010967:Plasmodium yoelii / Q000254:growth & development / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology
chemical_list: D000953:Antigens, Protozoan; D016056:Immunodominant Epitopes; D015848:Interleukin-5; D010455:Peptides; D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan; D007371:Interferon-gamma