RESUMO
Dendritic cells play a central role in the initiation of the immune response as they are the only antigen-presenting cells able to prime naive T cells. This makes the dendritic cells the vector of choice to use as a cell-based vaccine in immunotherapy. Although there are several strategies to deliver antigen to dendritic cells, the ones transfected with mRNA coding for tumor or viral antigens are able to induce potent antigen specific T-cell responses directed against multiple epitopes. In this review, we report several advances made in the field of anti-tumoral and anti-HIV immunotherapy using mRNA-transfected dendritic cells-based approaches.
Assuntos
Células Dendríticas/imunologia , Imunoterapia Ativa , RNA Mensageiro/genética , Animais , Apresentação de Antígeno , Antígenos CD/análise , Antígenos de Neoplasias/genética , Antígenos Virais/genética , Células Cultivadas/imunologia , Células Cultivadas/metabolismo , Ensaios Clínicos Fase I como Assunto , Células Dendríticas/classificação , Células Dendríticas/citologia , Células Dendríticas/metabolismo , Infecções por HIV/terapia , Humanos , Ativação Linfocitária , Camundongos , Células Mieloides/citologia , Neoplasias/terapia , RNA Neoplásico/genética , RNA Viral/genética , Linfócitos T/imunologia , TransfecçãoRESUMO
Mutations in the Escherichia coli (E. coli) and Salmonella lpxM gene have been shown to result in strains which grow normally and which produce a non-myristoylated lipopolysaccharide (nmLPS) with strongly reduced endotoxicity. Using homologous recombination, we inactivated the lpxM gene in BL21 (DE3), a strain widely used for the production of recombinant proteins. This led to a derivative unaffected in its capacity to support the production of recombinant proteins. This new strain expresses non-myristoylated LPS that induces markedly less activation and maturation of monocyte-derived dendritic cells (DC), as assessed by nuclear translocation of nuclear factor kappa B (NF-kappaB), production of TNF-alpha and IL-8 or expression of CD86. Activation of the main signal transducing receptor for extracellular LPS, Toll like receptor (TLR) 4 in conjunction with the soluble accessory protein MD-2 was also markedly decreased. The modified BL21 strain represents a new application of lpxM inactivation for the expression of proteins to be tested on dendritic cells or other LPS sensitive cells/receptor complexes. It is likely to be useful for the identification of new proteins activating the innate immune response and to reducing the risk linked with low level of endotoxin contamination in therapeutic recombinant proteins.
Assuntos
Células Dendríticas/citologia , Células Dendríticas/imunologia , Proteínas de Drosophila , Lipídeo A/genética , Lipídeo A/imunologia , Antígenos CD/metabolismo , Antígenos de Superfície/metabolismo , Antígeno B7-2 , Sequência de Bases , Diferenciação Celular , DNA Bacteriano/genética , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/metabolismo , Escherichia coli/genética , Escherichia coli/imunologia , Genes Bacterianos , Humanos , Técnicas In Vitro , Interleucina-8/biossíntese , Lipídeo A/farmacologia , Antígeno 96 de Linfócito , Glicoproteínas de Membrana/metabolismo , Mutagênese Insercional , Mutação , NF-kappa B/metabolismo , Receptores de Superfície Celular/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Receptor 4 Toll-Like , Receptores Toll-Like , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Outer membrane proteins (OMP) are expressed in Gram-negative bacterial cell wall. OmpA from Klebsiella pneumoniae (KpOmpA) has been shown to bind and to activate selectively antigen presenting cells (APCs), eliciting protective CTL responses. In this study, we investigated whether OmpX, another member of the OMP family and structurally related to OmpA, exhibits the same immune properties. Using recombinant OmpX from Escherichia coli (EcOmpX), we report that EcOmpX binds to and is internalized by human APCs. However, EcOmpX does not activate APCs. EcOmpX acts as an efficient carrier protein as it induces a potent and Th1/Th2 mixed anti-TNP humoral response. However, adjuvant is required to generate a protective anti-tumoral immune response in mice injected with a tumor model antigen coupled to EcOmpX. Collectively, these data show that EcOmpX is recognized by innate cells but does not activate them, suggesting that EcOmpX does not provide a signal danger to APCs. In conclusion, this study provides information on the molecular mechanisms involved in the recognition and activation of innate cells by bacterial outer membrane proteins.
Assuntos
Proteínas da Membrana Bacteriana Externa/imunologia , Proteínas de Escherichia coli/imunologia , Escherichia coli/imunologia , Hidrolases , Animais , Anticorpos Antineoplásicos/biossíntese , Formação de Anticorpos/imunologia , Antígenos de Bactérias/imunologia , Proteínas da Membrana Bacteriana Externa/biossíntese , Biotina , DNA Complementar/biossíntese , DNA Complementar/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/biossíntese , Citometria de Fluxo , Fluoresceína-5-Isotiocianato , Corantes Fluorescentes , Haptenos/imunologia , Humanos , Imunidade Celular/imunologia , Ativação de Macrófagos , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal , Monócitos/imunologia , Transplante de Neoplasias , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/imunologia , Toxoide Tetânico/imunologiaRESUMO
We have previously identified a mAb that binds to a molecule expressed preferentially on the surface of cycling thymocytes. In this study the molecule recognized by this mAb has been identified in the mouse as CD147 (basigin) by expression cloning. We show that CD147 expression correlates with cycling of immature thymocytes even in the absence of TCRbeta selection and that ligation of this molecule on immature fetal thymocytes inhibits their further development into mature T cells.