RESUMO
Research to enhance the efficiency of vaccines focuses mainly on improving either the adjuvant or the type and form of the antigen. This study evaluates the influence of the administration route on the efficiency of a peptide-based vaccine. Peptide vaccines are generally administered subcutaneously or intradermally, from where they must reach secondary lymphatic organs to induce an immune response. We analyzed the efficacy of peptide vaccines administered directly into a lymph node. Using a MHC class I-binding peptide from lymphocytic choriomeningitis virus, we found that intralymphatic injection enhanced immunogenicity by as much as 10(6) times when compared to subcutaneous and intradermal vaccination. Intralymphatic administration induced CD8 T cell responses with strong cytotoxic activity and IFN-gamma production that conferred long-term protection against viral infections and tumors. These results should have immediate implications for clinical immunotherapy of infectious disease and cancer.
Assuntos
Sistema Imunitário/efeitos dos fármacos , Vacinas de Subunidades Antigênicas/farmacologia , Animais , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Sistema Imunitário/imunologia , Injeções Intralinfáticas , Linfa/imunologia , Camundongos , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Linfócitos T Citotóxicos/efeitos dos fármacos , Linfócitos T Citotóxicos/imunologia , Vacinas de Subunidades Antigênicas/administração & dosagem , Vacinas de Subunidades Antigênicas/imunologia , Viroses/imunologia , Viroses/prevenção & controleRESUMO
CD44 is expressed in various isoforms on numerous cell types and tissues during embryogenesis and in the mature organism. CD44 may also be involved in tumor growth. To study the multiple roles of CD44, we abolished expression of all known isoforms of CD44 in mice by targeting exons encoding the invariant N-terminus region of the molecule. Surprisingly, mice were born in Mendelian ratio without any obvious developmental or neurological deficits. Hematological impairment was evidenced by altered tissue distribution of myeloid progenitors with increased levels of colony-forming unit-granulocyte-macrophage (CFU-GM) in bone marrow and reduced numbers of CFU-GM in spleen. Fetal liver colony-forming unit-spleen and granulocyte colony-stimulating factor mobilization assays, together with reduced CFU-GM in peripheral blood, suggested that progenitor egress from bone marrow was defective. In what was either a compensatory response to CD44 deficiency or an immunoregulatory defect, mice also developed exaggerated granuloma responses to Cryotosporidium parvum infection. Finally, tumor studies showed that SV40-transformed CD44-deficient fibroblasts were highly tumorigenic in nude mice, whereas reintroduction of CD44s expression into these fibroblasts resulted in a dramatic inhibition of tumor growth.
Assuntos
Granuloma/patologia , Hematopoese , Células-Tronco Hematopoéticas/fisiologia , Receptores de Hialuronatos/fisiologia , Neoplasias Experimentais/fisiopatologia , Processamento Alternativo , Animais , Formação de Anticorpos , Adesão Celular , Infecções por Corynebacterium/imunologia , Citotoxicidade Imunológica , Granulócitos/citologia , Ácido Hialurônico/metabolismo , Hipersensibilidade Tardia/imunologia , Imunidade Celular , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Teste de Cultura Mista de Linfócitos , Macrófagos/citologia , Camundongos , Camundongos Knockout , Camundongos Nus , Transplante de Neoplasias , Linfócitos T Citotóxicos/imunologia , Vírus da Estomatite Vesicular Indiana/imunologia , Viroses/imunologiaRESUMO
This study evaluated whether T-cell memory reflects increased precursor frequencies of specific long-lived T cells and/or a low-level immune response against some form of persistent antigen. Antivirally protective CD8+ T-cell memory was analyzed mostly in the original vaccinated host to assess the role of antigen in its maintenance. T-cell mediated resistance against reinfection was measured in the spleen and in peripheral solid organs with protocols that excluded protection by antibodies. In vivo protection was compared with detectable cytotoxic T-lymphocyte precursor frequencies determined in vitro. In the spleen, in vitro detectable cytotoxic T-lymphocyte precursor frequencies remained stable independently of antigen, conferring resistance against viral replication in the spleen during reinfection. In contrast, T-cell mediated resistance against reinfection of peripheral solid organs faded away in an antigen-dependent fashion within a few days or weeks. We show that only memory T cells persistently or freshly activated with antigen efficiently extravasate into peripheral organs, where cytotoxic T lymphocytes must be able to exert effector function immediately; both the capacity to extravasate and to rapidly exert effector function critically depend on restimulation by antigen. Our experiments document that the duration of T-cell memory protective against peripheral reinfection depended on the antigen dose used for immunization, was prolonged when additional antigen was provided, and was abrogated after removal of antigen. We conclude that T-cell mediated protective immunity against the usual peripheral routes of reinfection is antigen-dependent.
Assuntos
Antígenos/imunologia , Antígenos CD8/imunologia , Memória Imunológica , Linfócitos T Citotóxicos/imunologia , Animais , Antígenos Virais/imunologia , Ativação Linfocitária , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Vaccinia virus/imunologia , Interferência ViralRESUMO
The leukocyte integrin LFA-1 (CD11a/CD18) plays an important role in lymphocyte recirculation and homotypic interactions. Leukocytes from mice lacking CD11a displayed defects in in vitro homotypic aggregation, in proliferation in mixed lymphocyte reactions, and in response to mitogen. Mutant mice mounted normal cytotoxic T cell (CTL) responses against systemic LCMV and VSV infections and showed normal ex vivo CTL function. However, LFA-1-deficient mice did not reject immunogenic tumors grafted into footpads and did not demonstrate priming response against tumor-specific antigen. Thus CD11a deficiency causes a selective defect in induction of peripheral immune responses whereas responses to systemic infection are normal.
Assuntos
Antígenos CD18/imunologia , Integrinas/imunologia , Antígeno-1 Associado à Função Linfocitária/imunologia , Linfócitos T Citotóxicos/imunologia , Viroses/imunologia , Animais , Sequência de Bases , Antígenos CD18/genética , Homozigoto , Integrinas/genética , Antígeno-1 Associado à Função Linfocitária/genética , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Dados de Sequência Molecular , Mutagênese , Vírus da Estomatite Vesicular Indiana/imunologiaRESUMO
CD30 is found on Reed-Sternberg cells of Hodgkin's disease and on a variety of non-Hodgkin's lymphoma cells and is up-regulated on cells after Epstein-Barr virus, human T cell leukemia virus, and HIV infections. We report here that the thymus in CD30-deficient mice contains elevated numbers of thymocytes. Activation-induced death of thymocytes after CD3 cross-linking is impaired both in vitro and in vivo. Breeding the CD30 mutation separately into alpha beta TCR-or gamma delta TCR-transgenic mice revealed a gross defect in negative but not positive selection. Thus, like TNF-receptors and Fas/Apo-1, the CD30 receptor is involved in cell death signaling. It is also an important coreceptor that participates in thymic deletion.
Assuntos
Antígeno Ki-1/imunologia , Linfócitos T/imunologia , Animais , Linfócitos B/citologia , Linfócitos B/imunologia , Sequência de Bases , Morte Celular/imunologia , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Separação Celular , Deleção de Genes , Expressão Gênica/imunologia , Doença de Hodgkin/imunologia , Antígeno Ki-1/genética , Linfonodos/citologia , Masculino , Camundongos , Camundongos Mutantes , Dados de Sequência Molecular , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/genética , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Transdução de Sinais/imunologia , Superantígenos/imunologia , Linfócitos T/citologia , Linfócitos T/ultraestrutura , Timo/citologia , Timo/patologiaRESUMO
Only so-called "professional" antigen-presenting cells (APCs) of hematopoietic origin are believed capable of inducing T lymphocyte responses. However, fibroblasts transfected with viral proteins directly induced antiviral cytotoxic T lymphocyte responses in vivo, without involvement of host APCs. Fibroblasts induced T cells only in the milieu of lymphoid organs. Thus, antigen localization affects self-nonself discrimination and cell-based vaccine strategies.
Assuntos
Células Apresentadoras de Antígenos/imunologia , Fibroblastos/imunologia , Vírus da Coriomeningite Linfocítica/imunologia , Tecido Linfoide/imunologia , Linfócitos T Citotóxicos/imunologia , Proteínas Virais/imunologia , Animais , Citotoxicidade Imunológica , Glicoproteínas/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Células L , Coriomeningite Linfocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias/imunologia , Transfecção , Células Tumorais CultivadasRESUMO
In mice lacking the interleukin-2 receptor beta chain (IL-2R beta), T cells were shown to be spontaneously activated, resulting in exhaustive differentiation of B cells into plasma cells and the appearance of high serum concentrations of immunoglobulins G1 and E as well as autoantibodies that cause hemolytic anemia. Marked infiltrative granulocytopoiesis was also apparent, and the animals died after about 12 weeks. Depletion of CD4+ T cells in mutant mice rescued B cells without reversion of granulocyte abnormalities. T cells did not proliferate in response to polyclonal activators, nor could antigen-specific immune responses be elicited. Thus, IL-2R beta is required to keep the activation programs of T cells under control, to maintain homeostasis, and to prevent autoimmunity.