RESUMEN
Chronic lymphocytic leukaemia (CLL) cells convert CD14(+) cells from patients into 'nurse-like' cells (NLCs). CLL cells can also convert CD14(+) peripheral blood mononuclear cells (PBMCs) from healthy donors into cells with morphological similarities to NLCs (CD14(CLL) -cells). However it is unclear whether only CLL cells induce this conversion process. This study showed that CD14(+) PBMCs from healthy donors could also be converted into differentiated cells (CD14(B) -cells) by non-malignant B-cells. In order to identify changes specifically induced by CLL cells, we compared gene expression profiles of NLCs, CD14(CLL) -cells and CD14(B) -cells. CD14(+) cells cultured with CLL cells were more similar to NLCs than those cultured with non-malignant B-cells. The most significant changes induced by CLL cells were deregulation of the antigen presentation pathway and of genes related to immunity. NLCs had reduced levels of lysozyme activity, CD74 and HLA-DR in-vitro while expression of inhibitory FCGR2B was increased. These findings suggest an impaired immunocompetence of NLCs which, if found in-vivo, could contribute to the immunodeficiency in CLL patients.
Asunto(s)
Inmunocompetencia/genética , Leucemia Linfocítica Crónica de Células B/inmunología , Leucocitos Mononucleares/inmunología , Inmunidad Adaptativa/genética , Linfocitos B/inmunología , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Técnicas de Cocultivo , Perfilación de la Expresión Génica/métodos , Regulación Neoplásica de la Expresión Génica/genética , Antígenos HLA/metabolismo , Humanos , Inmunidad Innata/genética , Leucemia Linfocítica Crónica de Células B/genética , Receptores de Lipopolisacáridos/sangre , Muramidasa/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Células Tumorales CultivadasRESUMEN
The use of synthetic long peptides (SLP) has been proven to be a promising approach to induce adaptive immune responses in vaccination strategies. Here, we analyzed whether the efficiency to activate cytotoxic T cells by SLP-based vaccinations can be increased by conjugating SLPs to mannose residues. We could demonstrate that mannosylation of SLPs results in increased internalization by the mannose receptor (MR) on murine antigen-presenting cells. MR-mediated internalization targeted the mannosylated SLPs into early endosomes, from where they were cross-presented very efficiently compared to non-mannosylated SLPs. The influence of SLP mannosylation was specific for cross-presentation, as no influence on MHC II-restricted presentation was observed. Additionally, we showed that vaccination of mice with mannosylated SLPs containing epitopes from either ovalbumin or HPV E7 resulted in enhanced proliferation and activation of antigen-specific CD8+ T cells. These findings demonstrate that mannosylation of SLPs augments the induction of a cytotoxic T cell response in vitro and in vivo and might be a promising approach to induce cytotoxic T cell responses in e.g. cancer therapy and anti-viral immunity.
Asunto(s)
Células Presentadoras de Antígenos/inmunología , Antígenos/inmunología , Reactividad Cruzada , Inmunidad Celular/efectos de los fármacos , Manosa/inmunología , Péptidos/inmunología , Linfocitos T Citotóxicos/inmunología , Secuencia de Aminoácidos , Animales , Presentación de Antígeno , Células Presentadoras de Antígenos/citología , Antígenos/química , Proliferación Celular , Pollos , Endosomas/inmunología , Endosomas/metabolismo , Expresión Génica , Lectinas Tipo C/genética , Lectinas Tipo C/inmunología , Manosa/metabolismo , Receptor de Manosa , Lectinas de Unión a Manosa/genética , Lectinas de Unión a Manosa/inmunología , Ratones , Ratones Noqueados , Datos de Secuencia Molecular , Ovalbúmina/química , Ovalbúmina/inmunología , Proteínas E7 de Papillomavirus/química , Proteínas E7 de Papillomavirus/inmunología , Péptidos/administración & dosificación , Péptidos/síntesis química , Transporte de Proteínas , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/inmunología , Alineación de Secuencia , Linfocitos T Citotóxicos/citología , Linfocitos T Citotóxicos/metabolismoRESUMEN
Antigen cross-presentation enables dendritic cells (DCs) to present extracellular antigens on major histocompatibility complex (MHC) I molecules, a process that plays an important role in the induction of immune responses against viruses and tumors and in the induction of peripheral tolerance. In order to allow intracellular processing for cross-presentation, internalized antigens are targeted by distinct endocytic receptors toward specific endosomal compartments, where they are protected from rapid lysosomal degradation. From these compartments, antigens are processed for loading onto MHC I molecules. Such processing generally includes antigen transport into the cytoplasm, a process that is regulated by members of the ER-associated degradation (ERAD) machinery. After proteasomal degradation in the cytoplasm, antigen-derived peptides have been shown to be re-imported into the same endosomal compartment by endosomal transporter associated with antigen processing, another ER protein, which is recruited toward the endosomes after DC maturation. In our review, we highlight the recent advances on the molecular mechanisms of cross-presentation. We focus on the necessity of such antigen storage compartments and point out important parallels to MHC I-restricted presentation of endogenous antigens. We discuss the composition of such endosomes and the targeting of extracellular antigens into this compartment by specific endocytic receptors. Finally, we highlight recent advances on the recruitment of the cross-presentation machinery, like the members of the MHC I loading complex and the ERAD machinery, from the ER toward these storage compartments, a process that can be induced by antigen encounter or by activation of the dendritic cell after contact with endotoxins.