RESUMO
The level of laminin-binding protein (LBP) expression on cellular membranes was studied in three cell lines including 293 cells transformed by plasmide with human LBP gene. Vero cells show a high level of LBP on the cell surfaces and demonstrate a high level of the Venezuelan equine encephalomyelitis (VEE) virus replication. The inhibition of VEE virus replication was more than 200 times as much after treatment of Vero cell surfaces with monoclonal antibodies to human LBP. 293 cells have more low level of LBP on their surfaces but being transformed by plasmide with LBP human gene these cells showed an increase in the level of cellular LBP. The VEE virus replication in transformed cells (9S2) was more than 2000 times higher compared to 293 cells. The results obtained demonstrate a principal role of cellular LBP in VEE virus entry into mammalian cells. It can be proposed that LBP is a key cellular protein at the early stage of VEE virus replication in cells. So, LBP might be a target protein for development of some new generation of antiviral drugs that would be able to inhibit (enhance) the alphavirus replication in human cells.
Assuntos
Vírus da Encefalite Equina Venezuelana/fisiologia , Receptores de Laminina/fisiologia , Animais , Linhagem Celular , Chlorocebus aethiops , Humanos , Transfecção , Células Vero , Replicação ViralRESUMO
Adhesion is regarded as an important step in the pathogenesis of several microorganisms. Thus, the ability to recognize extracellular matrix proteins, such as laminin or fibronectin, has been correlated with invasiveness. Studying the already characterized laminin-binding protein of Paracoccidioides brasiliensis, the 43 kDa glycoprotein (gp43), we evaluated whether MAb 1.H12, raised against the laminin-binding protein from Staphylococcus aureus, cross-reacts with that fungal protein. By immunoblot analysis we show that MAb 1.H12 recognizes gp43. This interaction is able to inhibit the laminin-mediated adhesion to epithelial cells as well as the P. brasiliensis infection in vivo. Moreover, through immunoenzymatic assays, we show that MAb 1.H12 recognizes gp43 in solid phase and that this interaction is partially inhibited by the addition of anti-gp43 MAbs. These results show that MAb 1.H12 recognizes the gp43, suggesting the presence of an epitope similar to those found in the other laminin-binding proteins from phylogenetically very distant cells. These findings reinforce the possibility of evolutionary conservation of such epitopes.
Assuntos
Anticorpos Monoclonais , Laminina/metabolismo , Paracoccidioides/fisiologia , Receptores de Laminina/fisiologia , Staphylococcus aureus/imunologia , Animais , Sítios de Ligação , Adesão Celular , Linhagem Celular , Cricetinae , Cães , Epitélio/microbiologia , Epitélio/ultraestrutura , Epitopos/análise , Proteínas da Matriz Extracelular/metabolismo , Granuloma/microbiologia , Granuloma/patologia , Humanos , Rim , Neoplasias Pulmonares , Masculino , Microscopia Eletrônica de Varredura , Paracoccidioides/imunologia , Paracoccidioides/ultraestrutura , Receptores de Laminina/análise , Receptores de Laminina/imunologia , Testículo/microbiologia , Testículo/patologiaRESUMO
F9 mouse teratocarcinoma cells have a high capacity to adhere to laminin and we identified alpha 6/beta 1 integrin as the principal laminin-binding protein present in these cells. F9 cells differentiated into parietal endoderm when monolayer cultures were treated with retinoic acid and dibutyryl cyclic AMP. In this process a decreased adherence to laminin was observed due to a lower expression of alpha 6/beta 1 integrin on the cell surface.
Assuntos
Regulação para Baixo , Integrinas/fisiologia , Laminina/fisiologia , Receptores de Laminina/fisiologia , Tretinoína/farmacologia , Animais , Bucladesina/farmacologia , Adesão Celular , Diferenciação Celular/efeitos dos fármacos , Integrina alfa6beta1 , Integrinas/metabolismo , Laminina/metabolismo , Camundongos , Ligação Proteica , Receptores de Laminina/metabolismo , Células Tumorais Cultivadas/efeitos dos fármacosRESUMO
F9 mouse teratocarcinoma cells have a high capacity to adhere to laminin and we identified alpha6/beta1 integrin as the principal laminin-binding protein present in these cells. F9 cells differentiated into parietal endoderm when monolayer cultures were treated with retinoic acid and dibutyryl cyclic AMP. In this process a decreased adherence to laminin was observed due to a lower expression of alpha6/beta1 integrin on the cell surface