Journal article
Capsule Enhances Pneumococcal Colonization by Limiting Mucus-Mediated Clearance
Infection and immunity, v 75(1), pp 83-90
01 Jan 2007
PMID: 17088346
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Expression of a polysaccharide capsule is required for the full pathogenicity of many mucosal pathogens such as
Streptococcus pneumoniae
. Although capsule allows for evasion of opsonization and subsequent phagocytosis during invasive infection, its role during mucosal colonization, the organism's commensal state, remains unknown. Using a mouse model, we demonstrate that unencapsulated mutants remain capable of nasal colonization but at a reduced density and duration compared to those of their encapsulated parent strains. This deficit in colonization was not due to increased susceptibility to opsonophagocytic clearance involving complement, antibody, or the influx of Ly-6G-positive cells, including neutrophils seen during carriage. Rather, unencapsulated mutants remain agglutinated within lumenal mucus and, thus, are less likely to transit to the epithelial surface where stable colonization occurs. Studies of in vitro binding to immobilized human airway mucus confirmed the inhibitory effect of encapsulation. Likewise, pneumococcal variants expressing larger amounts of negatively charged capsule per cell were less likely to adhere to surfaces coated with human mucus and more likely to evade initial clearance in vivo. Removal of negatively charged sialic acid residues by pretreatment of mucus with neuraminidase diminished the antiadhesive effect of encapsulation. This suggests that the inhibitory effect of encapsulation on mucus binding may be mediated by electrostatic repulsion and offers an explanation for the predominance of anionic polysaccharides among the diverse array of unique capsule types. In conclusion, our findings demonstrate that capsule confers an advantage to mucosal pathogens distinct from its role in inhibition of opsonophagocytosis—escape from entrapment in lumenal mucus.
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Details
- Title
- Capsule Enhances Pneumococcal Colonization by Limiting Mucus-Mediated Clearance
- Creators
- Aaron L. Nelson - University of PennsylvaniaAoife M. Roche - University of PennsylvaniaJane M. Gould - University of PennsylvaniaKannie Chim - University of PennsylvaniaAdam J. Ratner - University of PennsylvaniaJeffrey N. Weiser - University of Pennsylvania
- Publication Details
- Infection and immunity, v 75(1), pp 83-90
- Publisher
- American Society for Microbiology
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Pediatrics
- Web of Science ID
- WOS:000243230500008
- Scopus ID
- 2-s2.0-33846015873
- Other Identifier
- 991021838280004721
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InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Immunology
- Infectious Diseases