SBNeC 2010
Resumo:B.014


Prêmio
B.014Olfactory ensheathing cells as putative host cells for Streptococcus pneumoniae: evidence of bacterial invasion via mannose receptor-mediated endocytosis
Autores:Hugo Macedo Ramos (IBCCFº/UFRJ - Instituto de Biofísica Carlos Chagas Filho-UFRJ) ; Fernanda S.o.campos (IBCCFº/UFRJ - Instituto de Biofísica Carlos Chagas Filho-UFRJ) ; Lítia A. Carvalho (IBCCFº/UFRJ - Instituto de Biofísica Carlos Chagas Filho-UFRJ) ; Lucia Martins Teixeira (IMPPG/UFRJ - Instituto de Microbiologia Prof. Paulo de Góes-UFRJ) ; Leny Alves Cavalcante (IBCCFº/UFRJ - Instituto de Biofísica Carlos Chagas Filho-UFRJ) ; Wagner Baetas da Cruz (IBCCFº/UFRJ - Instituto de Biofísica Carlos Chagas Filho-UFRJIBCCFº/MACAÉ/UFRJ - Instituto de Biofísica Carlos Chagas Filho-Campus Macaé)

Resumo

Olfactory ensheathing cells (OECs) comprise a special glial type derived from progenitors in the olfactory mucosa that ensheath olfactory receptor axons. Axonal bundles extend toward the cribiform plate and enter the brain via the olfactory phila, thus, providing a potential route for access of pathogens to the brain. Streptococcus pneumoniae (Sp) is the most common agent for acute bacterial rhinosinusitis, that may evolve to meningitis, and has a polysaccharide capsule rich in mannosyl residues. Since OECs express the mannose receptor (MR), we tested whether they could internalize Sp via MR in vitro. OEC cultures were infected by a suspension of Sp (ATCC 49619) in a 100:1 bacteria/cells ratio. Internalized bacteria, stained by an anti-pneumoccocus polyclonal antibody, resulted from this exposure and competition assays, performed by infecting cultures in the presence of mannan (100 μg/mL), showed a dramatic reduction (about 15-fold) in their number. To confirm that the MR was involved in the uptake of Sp, OECs were reacted with a polyclonal antibody against the MR C-terminus (anti-cMR) and (fixed) bacteria were visualized with Sytox green, an optimal stain for bacterial DNA. These results showed intense, selective immunoreaction of OECs with anticMR in cell compartments containing bacteria. Our data suggest involvement of MR in bacterial adhesion to OEC surface, and possibly in their internalization. These data are also coherent with a role of OECs as a host cell prior to (and during) bacterial invasion of the brain.


Palavras-chave:  innate immunity, pattern recognition receptors (PRRs), pathogen-associated molecular patterns, pneumococcal meningitis, glycoconjugates