RESUMO
In this study, we evaluate two Listeria monocytogenes strains that express influenza nucleoprotein (NP) sequences for their ability to protect against challenge with influenza-virus. The construction of one strain, which expresses only the Kd restricted NP epitope (NP 147-155), is described in this study; the other strain, which expresses the full NP sequence in the form of a fusion protein, has been described previously. The ability of the two strains to present the Kd restricted NP epitope in vitro and induce NP-specific CTL in vivo is also described. Mice immunized by the intravenous route with either strain cleared a subsequent (3 weeks post-immunization) influenza virus infection more rapidly as indicated by reduced virus titers in the lungs 5 days after challenge. Efficacy of both recombinant L. monocytogenes strains as vaccines in this system was equivalent and equal to that of recombinant vaccinia expressing NP.
Assuntos
Vírus da Influenza A/imunologia , Listeria monocytogenes/imunologia , Nucleoproteínas , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Vacinas Sintéticas/imunologia , Vacinas Virais/imunologia , Animais , Linhagem Celular , Epitopos/metabolismo , Imunidade Inata , Vírus da Influenza A/metabolismo , Listeria monocytogenes/genética , Pulmão/virologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos BALB C , Proteínas do Nucleocapsídeo , Infecções por Orthomyxoviridae/terapia , Proteínas Recombinantes de Fusão/biossíntese , Linfócitos T Citotóxicos/imunologia , Vacinas Sintéticas/biossíntese , Proteínas do Core Viral/imunologia , Proteínas do Core Viral/metabolismo , Vacinas Virais/genéticaRESUMO
Listeria monocytogenes has recently been exploited as a vector for targeting antigens to the immune system. In the past year it has been shown to be particularly effective as a tumor antigen vector. Here we set its potency as a cancer vaccine in the context of the type of immunity induced by this facultative intracellular bacterium.
Assuntos
Vacinas Anticâncer/isolamento & purificação , Listeria monocytogenes/imunologia , Animais , Apresentação de Antígeno , Antígenos de Neoplasias/genética , Citocinas/imunologia , Vetores Genéticos , Interferon gama/imunologia , Interleucina-1/imunologia , Interleucina-12/imunologia , Listeria monocytogenes/genética , Listeriose/imunologia , Camundongos , Subpopulações de Linfócitos T/imunologia , Fator de Necrose Tumoral alfa/imunologiaRESUMO
We have shown previously that Listeria monocytogenes, a gram-positive, facultative intracellular bacterium, is a potent vector for targeting tumor-specific antigens to the immune system. After parenteral administration, we observed protection against both renal and colorectal mouse tumors and regression of established renal tumors. In the present study, we have exploited the fact that the normal route of infection of this organism is through the gut. We show that an L. monocytogenes recombinant that expresses a model tumor antigen is an effective cancer immunotherapeutic agent when delivered orally in that it causes regression of established, macroscopic mouse renal and colorectal tumors expressing the same antigen.
Assuntos
Vacinas Bacterianas/uso terapêutico , Listeria monocytogenes/imunologia , Neoplasias Experimentais/terapia , Proteínas de Ligação a RNA , Vacinas Sintéticas/uso terapêutico , Administração Oral , Animais , Antígenos de Neoplasias/imunologia , Antígenos Virais/genética , Antígenos Virais/imunologia , Carcinoma de Células Renais/imunologia , Carcinoma de Células Renais/terapia , Neoplasias do Colo/imunologia , Neoplasias do Colo/terapia , Produtos do Gene gag/metabolismo , Imunoterapia Ativa , Neoplasias Renais/imunologia , Neoplasias Renais/terapia , Listeria monocytogenes/genética , Melanoma Experimental/terapia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Neoplasias Experimentais/imunologia , Proteínas do Nucleocapsídeo , Nucleoproteínas/imunologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Linfócitos T Citotóxicos/imunologia , Transdução Genética , Células Tumorais Cultivadas , Proteínas do Core Viral/imunologiaRESUMO
Listeria monocytogenes is an intracellular organism that has the unusual ability to live in the cytoplasm of the cell. It is thus a good vector for targeting protein antigens to the cellular arm of the immune response. Here we use a model system, consisting of colon and renal carcinomas that express the influenza virus nucleoprotein and a recombinant L. monocytogenes that secrets this antigen, to test the potential of this organism as a cancer immunotherapeutic agent. We show that this recombinant organism can not only protect mice against lethal challenge with tumour cells that express the antigen, but can also cause regression of established macroscopic tumours in an antigen-specific T-cell-dependent manner.
Assuntos
Antígenos de Neoplasias/imunologia , Antineoplásicos/imunologia , Neoplasias do Colo/imunologia , Neoplasias Renais/imunologia , Listeria monocytogenes/imunologia , Vacinas Sintéticas/imunologia , Animais , Especificidade de Anticorpos , Neoplasias do Colo/prevenção & controle , Neoplasias Renais/prevenção & controle , Camundongos , Camundongos Endogâmicos BALB C , Linfócitos T/imunologia , Células Tumorais Cultivadas/imunologiaRESUMO
Listeria monocytogenes is a facultative intracellular pathogen that grows in the cytoplasm of infected host cells. We examined the capacity of L. monocytogenes to introduce influenza nucleoprotein (NP) into the class I pathway of antigen presentation both in vitro and in vivo. Recombinant L. monocytogenes secreting a fusion of listeriolysin O and NP (LLO-NP) targeted infected cells for lysis by NP-specific class I-restricted cytotoxic T cells. Antigen presentation occurred in the context of three different class I haplotypes in vitro. A hemolysin-negative L. monocytogenes strain expressing LLO-NP was able to present in a class II-restricted manner. However, it failed to target infected cells for lysis by CD8+ T cells, indicating that hemolysin-dependent bacterial escape from the vacuole is necessary for class I presentation in vitro. Immunization of mice with a recombinant L. monocytogenes strain that stably expressed and secreted LLO-NP induced NP-specific CD8+ cytotoxic T lymphocytes. These studies have implications for the use of L. monocytogenes to deliver potentially any antigen to the class I pathway in vivo.
