PstS-1, the 38-kDa Mycobacterium tuberculosis Glycoprotein, is an Adhesin, Which Binds the Macrophage Mannose Receptor and Promotes Phagocytosis


Por: Esparza, M, Palomares, B, Garcia, T, Espinosa, P, Zenteno, E, Mancilla, R

Publicada: 1 ene 2015
Categoría: Immunology

Resumen:
Mycobacterium tuberculosis, the primary causative agent of tuberculosis, infects macrophages and transforms the hostile intracellular environment into a permissive niche. M.tuberculosis infects macrophages using a variety of microbial ligand/cell receptor systems. In this study, binding assays with biotin-labelled mycobacterial cell wall proteins revealed five Concanavalin A-reactive proteins that bind macrophages. Among these proteins, we identified PstS-1, a 38-kDa M.tuberculosis mannosylated glycolipoprotein, and characterized it as an adhesin. Inhibition assays with mannan and immunoprecipitation demonstrated that PstS-1 binds the mannose receptor. We purified PstS-1 to 95.9% purity using ion exchange chromatography. The presence of mannose in purified PstS-1 was demonstrated by Concanavalin A interaction, which was abolished in the presence of sodium m-periodate and -D-mannosidase. Gas chromatography revealed that purified PstS-1 contained 1% of carbohydrates by weight, which was mainly mannose. Finally, we used fluorescent microbeads coated with purified PstS-1 in phagocytosis assays and discovered that microbead uptake was inhibited by the pre-incubation of cells with GlcNAc, mannan and -methyl mannoside. The interaction of PstS-1 coated beads with the mannose receptor was confirmed by confocal colocalization studies that showed high Pearson and Manders's colocalization coefficients. Our findings contribute to a better understanding of the strategies M.tuberculosis uses to infect host cells, the critical first step in the pathogenesis of tuberculosis.

Filiaciones:
Esparza, M:
 Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Inmunol, Mexico City 04510, DF, Mexico

Palomares, B:
 Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Inmunol, Mexico City 04510, DF, Mexico

Garcia, T:
 Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Inmunol, Mexico City 04510, DF, Mexico

Espinosa, P:
 Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Inmunol, Mexico City 04510, DF, Mexico

Zenteno, E:
 Univ Nacl Autonoma Mexico, Fac Med, Dept Bioquim, Mexico City 04510, DF, Mexico

Mancilla, R:
 Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Inmunol, Mexico City 04510, DF, Mexico
ISSN: 03009475
Editorial
Blackwell Publishing Ltd, COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA, Estados Unidos America
Tipo de documento: Article
Volumen: 81 Número: 1
Páginas: 46-55
WOS Id: 000346771300007
ID de PubMed: 25359607

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