Pneumococcal Capsule
Pneumococcal Capsule - Related Videos
07:47
Experimental Human Pneumococcal Carriage
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Cited by 80 •
2013
Experimental human pneumococcal carriage offers a natural model of carriage and a potential model for use in vaccine development. This technique is valuable yet complex and involves clinical risk by introducing a pathogen into a human. We have developed a detailed protocol.
09:20
Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay
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Cited by 8 •
2014
In vitro adherence assays can be used to study the attachment of Streptococcus pneumoniae to epithelial cell monolayers and to investigate potential interventions such as the use of probiotics for inhibiting pneumococcal colonization.
05:24
Teratoma Generation in the Testis Capsule
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Cited by 25 •
2011
Human pluripotent stem cells (hPSCs) have the potential to treat a myriad of different diseases. The utility of these cells lies in the fact that they can differentiate into any cell type in the body. Here we describe the teratoma assay, which is used to demonstrate the pluripotence of hPSCs.
11:32
Following in Real Time the Impact of Pneumococcal Virulence Factors in an Acute Mouse Pneumonia Model Using Bioluminescent Bacteria
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Cited by 18 •
2014
Streptococcus pneumoniae is the leading pathogen causing severe community-acquired pneumonia and responsible for over 2 million deaths worldwide. The impact of bacterial factors implicated in fitness or virulence can be monitored in real-time in an acute mouse pneumonia or bacteremia model using bioluminescent bacteria.
02:17
Separation of Bacteria by Capsule Amount Using a Discontinuous Density Gradient
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2025
Source: Feltwell, T., et.al. Separating Bacteria by Capsule Amount Using a Discontinuous Density Gradient. J. Vis. Exp. (2019)This video demonstrates the use of a discontinuous density gradient to separate bacterial strains based on capsule amount. By centrifuging a transposon mutant library through the gradient, bacteria with different capsule densities localize to distinct layers. The separated fractions can then be collected for downstream analysis.
FAQs
Capsule-specific antibodies can make pneumococci more readily recognized and engulfed by phagocytes through opsonization, the coating of a microbe that promotes uptake. This antibody-mediated effect counteracts the capsule’s interference with host defenses and provides a mechanistic basis for studying protective immunity. In infection research, antibody activity is therefore linked to clearance and resistance to disease.
Strains with different capsule compositions are assigned distinct serotypes. This variation matters because immune recognition and antibody protection are studied in relation to particular capsule types rather than treating all pneumococci as identical. Consequently, capsule composition provides a useful biological marker for comparing strains and interpreting differences in immunity, infection patterns, and epidemiology.
Its effect is cumulative rather than limited to one immune pathway. The surface barrier reduces bacterial recognition, limits complement deposition, and makes uptake by phagocytes less efficient. These linked effects help explain why capsule expression is a major virulence determinant: interference with host defense can support persistence in tissues and blood, where immune clearance is especially important.
Antibody studies ask whether recognition of a particular capsule type leads to opsonization and protective immunity. This focus connects an immune response to the capsule’s contribution to persistence: antibodies may counter the surface barrier sufficiently to improve phagocytic uptake. Comparing antibody activity across capsule types can therefore clarify which responses are relevant to protection against pneumococcal infection.
Serotyping classifies pneumococci according to differences in capsule composition, creating a consistent way to distinguish circulating strains. Researchers can then use those categories in epidemiologic studies to follow which serotypes are associated with infection and how their distribution changes over time. The approach links a surface feature of the bacterium with population-level patterns of disease.
Capsule-based conjugate vaccines are used to prevent invasive pneumococcal disease, but their relevance also extends to population biology. By targeting capsule-defined types, vaccination can alter which pneumococcal populations circulate after implementation. Researchers therefore examine both the protective effect against invasive disease and the resulting changes in serotype distribution when assessing vaccine impact.