RESUMO
NK cells kill target cells mainly via exocytosis of granules containing perforin (perf) and granzymes (gzm). In vitro, gzm delivery into the target cell cytosol results in apoptosis, and induction of apoptosis is severely impaired in the absence of gzm A and B. However, their importance for in vivo cytotoxicity by cytotoxic T cells has been questioned. We used an in vivo NK cytotoxicity assay, in which splenocytes from wild-type and ß(2)microglobulin-deficient (MHC-I(neg)) mice are co-injected into recipients whose NK cells were activated by virus infection or synthetic Toll-like receptor ligands. Elimination of adoptively transferred MHC-I(neg) splenocytes was unimpaired in the absence of gzmA and gzmB, but dependent on perforin. This target cell rejection was NK cell dependent, since NK cell depletion abrogated it. Furthermore, target cell elimination in vivo was equally rapid in both wild-type and gzmAxB-deficient recipients, with the majority of specific target cells lost from lymphoid tissue within less than one to two hours after transfer. Thus, similar to T cell cytotoxicity, the contribution of gzmA and B to in vivo target cell elimination remains unresolved.
Assuntos
Antígenos de Histocompatibilidade Classe I/imunologia , Células Matadoras Naturais/imunologia , Ativação Linfocitária/imunologia , Animais , Citotoxicidade Imunológica/genética , Feminino , Regulação da Expressão Gênica , Granzimas/deficiência , Granzimas/metabolismo , Células Matadoras Naturais/virologia , Camundongos , Camundongos Endogâmicos C57BL , Perforina/metabolismo , Vírus da Floresta de Semliki/fisiologiaRESUMO
Cytotoxic T (Tc) cells lyse target cells via exocytosis of granules containing perforin (perf) and granzymes (gzm). In vitro, gzm delivery into the target cell cytosol results in apoptosis, and in the absence of gzm A and B the induction of apoptosis is severely impaired. However, using in vivo Tc cell killing assays, we find that virus-immune, gzm A x B-deficient (gzmAxB(-/-)) mice are competent to eliminate adoptively transferred target cells pulsed with an immunodominant Tc cell determinant as rapidly and completely as their wild-type counterparts. Specific target cell elimination occurred with similar kinetics in both spleen and lymph nodes. Thus, neither gzmA nor gzmB are required for rapid and efficient in vivo cytotoxicity by Tc cells.
Assuntos
Citotoxicidade Imunológica , Granzimas/fisiologia , Linfócitos T Citotóxicos/imunologia , Animais , Morte Celular/genética , Morte Celular/imunologia , Citotoxicidade Imunológica/genética , Vírus da Ectromelia/imunologia , Ectromelia Infecciosa/enzimologia , Ectromelia Infecciosa/imunologia , Ectromelia Infecciosa/patologia , Granzimas/deficiência , Granzimas/genética , Vírus da Influenza A/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infecções por Orthomyxoviridae/enzimologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/patologia , Linfócitos T Citotóxicos/patologia , Linfócitos T Citotóxicos/virologia , Fatores de TempoRESUMO
Many viruses, including flaviviruses, display affinity for cell surface heparan sulfate (HS) proteoglycans with biological relevance in virus attachment/entry. This raises the possibility of the application of HS mimetics in antiviral therapy. We have evaluated the antiviral effect of the sulfated polysaccharides, suramin, pentosan polysulfate (PPS) and PI-88, which are currently approved or in trial for clinical use, against dengue virus (DEN) and the encephalitic flaviviruses, Japanese encephalitis virus, West Nile virus, and Murray Valley encephalitis virus. A flow cytometry-based method for the measurement of inhibition of virus infectivity was developed, which showed the in vitro antiviral activity of the three compounds, albeit with differences in efficiency which were virus-dependent. The 50% effective concentration (EC(50)) values for DEN inhibition were in the order: PPSAssuntos
Antivirais/farmacologia
, Vírus da Dengue/efeitos dos fármacos
, Dengue/tratamento farmacológico
, Vírus da Encefalite Japonesa (Subgrupo)/efeitos dos fármacos
, Heparitina Sulfato/farmacologia
, Oligossacarídeos/farmacologia
, Animais
, Antivirais/química
, Antivirais/uso terapêutico
, Linhagem Celular
, Modelos Animais de Doenças
, Avaliação Pré-Clínica de Medicamentos
, Encefalite por Arbovirus/tratamento farmacológico
, Feminino
, Infecções por Flavivirus/tratamento farmacológico
, Heparitina Sulfato/uso terapêutico
, Injeções Intraperitoneais
, Masculino
, Camundongos
, Camundongos Endogâmicos C57BL
, Camundongos Knockout
, Oligossacarídeos/química
, Oligossacarídeos/uso terapêutico
, Poliéster Sulfúrico de Pentosana/química
, Poliéster Sulfúrico de Pentosana/farmacologia
, Poliéster Sulfúrico de Pentosana/uso terapêutico
, Suramina/química
, Suramina/farmacologia
, Suramina/uso terapêutico
, Resultado do Tratamento