Merja Väkeväinen

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We evaluated the effect of aging on the functional activity of naturally acquired anti-pneumococcal antibodies, the function of neutrophils in phagocytic killing of opsonized pneumococci, and the complement activity. Opsonic activities of antibodies to all tested pneumococcal serotypes were significantly lower and phagocytic killing of pneumococci by(More)
The polysaccharide capsule of Streptococcus pneumoniae inhibits phagocytic killing by innate immune mechanisms. Certain serotypes are associated with invasive disease while others with a nasopharyngeal carriage. The invasiveness of serotypes may partly be explained by ability to resist deposition of complement (C3) on the bacterial surface and consequent(More)
The polysaccharide capsule is a major virulence mechanism of Streptococcus pneumoniae, shielding the bacterium from phagocytes. Capsule types may differ in their abilities to resist immune defense. Antibody-mediated complement activation and opsonophagocytosis are crucial in protection against pneumococcus. Conjugate vaccine trials suggest imperfect(More)
The polysaccharide capsule is a major virulence factor of Streptococcus pneumoniae; it affects complement resistance and shields the bacterium from phagocytes. Certain capsular serotypes appear to be better able to cause invasive disease than others. Serotypes 1 and 5 are common causes of invasive disease but are rarely isolated from healthy carriers,(More)
Finnish and Israeli infants received an 11-valent mixed-carrier pneumococcal conjugate vaccine with or without aluminum adjuvant at 2, 4, 6, and 12 months of age. The relative avidity of serotype 1-, 5-, 6B-, 14-, 19F-, and 23F-specific IgG antibodies in serum obtained at 7, 12, and 13 months of age was measured by EIA, using thiocyanate as a chaotropic(More)
Monitoring of anti-drug antibodies (ADAbs) or serum concentrations of biologicals in treatment of rheumatoid arthritis could provide an explanation for a loss of efficacy and help in the choice of subsequent medication. Current clinical practices do not generally include such monitoring of tumor necrosis factor (TNF)-α blockers on a routine basis. The main(More)
Elderly individuals are susceptible to pneumococcal infections. Although factors contributing to the increased susceptibility of the elderly to bacterial infections may be several, compromised immune function, a consequence of normal human ageing, is widely accepted to play a role. We evaluated the effect of ageing on the concentrations of naturally(More)
In the Finnish Otitis Media Vaccine Trial, the now-licensed pneumococcal conjugate vaccine containing polysaccharides conjugated to protein CRM(197) (PncCRM) and the experimental pneumococcal polysaccharide-meningococcal outer membrane protein complex conjugate vaccine (PncOMPC), showed similar efficacy profiles against acute otitis media despite different(More)
Host protection against Streptococcus pneumoniae is mainly mediated by opsonin-dependent phagocytosis. Several techniques for measuring opsonophagocytic activity (OPA) of antibodies to S. pneumoniae have been standardized and used. These include the viable cell-assay, flow-cytometric assays, and an assay utilizing radiolabeled bacteria. Using these(More)
Streptococcus pneumoniae serotypes 6B and 6A are important causes of infections, yet only 6B is included in current vaccines. It is, therefore, crucial to evaluate whether functional antibodies are produced against both types after vaccination. Concentration and opsonophagocytic activity (OPA) of antibodies to 6B and 6A polysaccharides were determined in(More)