title: In vivo activation of naive CD4+ T cells in nasal mucosa-associated lymphoid tissue following intranasal immunization with recombinant Streptococcus gordonii.
abstract: The antigen-specific primary activation of CD4+ T cells was studied in vivo by adoptive transfer of ovalbumin-specific transgenic T cells (KJ1-26+ CD4+) following intranasal immunization with recombinant Streptococcus gordonii. A strain of S. gordonii expressing on its surface a model vaccine antigen fused to the ovalbumin (OVA) peptide from position 323 to 339 was constructed and used to study the OVA-specific T-cell activation in nasal mucosa-associated lymphoid tissue (NALT), lymph nodes, and spleens of mice immunized by the intranasal route. The recombinant strain, but not the wild type, activated the OVA-specific CD4+ T-cell population in the NALT (89% of KJ1-26+ CD4+ T cells) just 3 days following immunization. In the cervical lymph nodes and in the spleen, the percentage of proliferating cells was initially low, but it reached the peak of activation at day 5 (90%). This antigen-specific clonal expansion of KJ1-26+ CD4+ T cells after intranasal immunization was obtained with live and inactivated recombinant bacteria, and it indicates that the NALT is the site of antigen-specific T-cell priming.
authors.affiliation: LAMMB, Dipartimento di Biologia Molecolare, Università di Siena, Siena, Italy. medaglini@unisi.it
authors.forename: Donata
authors.initials: D
authors.lastname: Medaglini
authors.forename: Annalisa
authors.initials: A
authors.lastname: Ciabattini
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Cuppone
authors.forename: Caterina
authors.initials: C
authors.lastname: Costa
authors.forename: Susanna
authors.initials: S
authors.lastname: Ricci
authors.forename: Massimo
authors.initials: M
authors.lastname: Costalonga
authors.forename: Gianni
authors.initials: G
authors.lastname: Pozzi
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D007114:Immunization; D008213:Lymphocyte Activation; D008221:Lymphoid Tissue / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009297:Nasal Mucosa / Q000276:immunology*; D022541:Streptococcal Vaccines / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000276:immunology*
chemical_list: D022541:Streptococcal Vaccines; D014614:Vaccines, Synthetic