pIgR and PECAM-1 bind to pneumococcal adhesins RrgA and PspC mediating bacterial brain invasion

F Iovino, JY Engelen-Lee, M Brouwer… - Journal of Experimental …, 2017 - rupress.org
F Iovino, JY Engelen-Lee, M Brouwer, D van de Beek, A van der Ende, M Valls Seron…
Journal of Experimental Medicine, 2017rupress.org
Streptococcus pneumoniae is the main cause of bacterial meningitis, a life-threating disease
with a high case fatality rate despite treatment with antibiotics. Pneumococci cause
meningitis by invading the blood and penetrating the blood–brain barrier (BBB). Using
stimulated emission depletion (STED) super-resolution microscopy of brain biopsies from
patients who died of pneumococcal meningitis, we observe that pneumococci colocalize
with the two BBB endothelial receptors: polymeric immunoglobulin receptor (pIgR) and …
Streptococcus pneumoniae is the main cause of bacterial meningitis, a life-threating disease with a high case fatality rate despite treatment with antibiotics. Pneumococci cause meningitis by invading the blood and penetrating the blood–brain barrier (BBB). Using stimulated emission depletion (STED) super-resolution microscopy of brain biopsies from patients who died of pneumococcal meningitis, we observe that pneumococci colocalize with the two BBB endothelial receptors: polymeric immunoglobulin receptor (pIgR) and platelet endothelial cell adhesion molecule (PECAM-1). We show that the major adhesin of the pneumococcal pilus-1, RrgA, binds both receptors, whereas the choline binding protein PspC binds, but to a lower extent, only pIgR. Using a bacteremia-derived meningitis model and mutant mice, as well as antibodies against the two receptors, we prevent pneumococcal entry into the brain and meningitis development. By adding antibodies to antibiotic (ceftriaxone)-treated mice, we further reduce the bacterial burden in the brain. Our data suggest that inhibition of pIgR and PECAM-1 has the potential to prevent pneumococcal meningitis.
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