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Antibody response to pneumococcal capsular polysaccharides in children with acute otitis media
Anu Soininen1, Mika Lahdenkari, Terhi Kilpi
1Department of Vaccines, National Public Health Institute, Helsinki, Finland.
Insights
Antibody responses to common pneumococcal serotypes in young children with acute otitis media (AOM) varied by age and serotype. Older children showed better responses, but only some serotypes, like 23F, elicited frequent responses, though often with low antibody levels.
Area of Science:
- Pediatric Infectious Diseases
- Immunology
- Microbiology
Background:
- Investigated antibody responses to specific pneumococcal capsular polysaccharides in children under two years old experiencing acute otitis media (AOM).
- Focused on serotypes 6A, 6B, 11A, 14, 19F, and 23F, frequently found in nasopharyngeal carriage and AOM in Finnish children.
Purpose of the Study:
- To characterize the antibody response to pneumococcal capsular polysaccharides in young children with AOM.
- To understand the influence of age and specific Streptococcus pneumoniae serotypes on antibody production.
Main Methods:
- Measured serum antibody concentrations to pneumococcal capsular polysaccharides (types 6B, 11A, 14, 19F, 23F) using enzyme immunoassay.
- Analyzed acute and convalescent sera from children diagnosed with AOM.
Main Results:
- Antibody responses (≥2-fold increase) were infrequent and dependent on child's age and pneumococcal serotype.
- Children over 12 months old demonstrated a higher likelihood of antibody response compared to younger children.
- Serotypes 6A, 6B, and 19F showed low response rates, while 11A and 14 showed moderate rates. Type 23F elicited frequent responses, but with low antibody concentrations that typically declined post-infection. AOM due to type 14 resulted in persistent high antibody levels.
Conclusions:
- Different Streptococcus pneumoniae serotypes exhibit distinct immunogenicity.
- Infection with specific pneumococcal serotypes leads to quantitative and qualitative variations in antibody production.
Background:
To describe the antibody response to pneumococcal capsular polysaccharides in children <2 years of age with pneumococcal acute otitis media (AOM) caused by serotypes 6A, 6B, 11A, 14, 19F or 23F. These serotypes were commonly found in both nasopharyngeal carriage and AOM in children of the study population in Finland.
Methods:
Serum antibody concentrations to pneumococcal capsular polysaccharides of types 6B, 11A, 14, 19F and 23F were measured by enzyme immunoassay in acute and convalescent sera from children with AOM.
Results:
Responses (at least 2-fold increase of antibody concentration) were relatively infrequent and varied with both the age of the child and the serotype of the Streptococcus pneumoniae isolated from the middle ear fluid. Children older than 12 months were more likely to have antibody responses than were younger children. Responses were seen only infrequently to types 6A, 6B or 19F (1 of 14, 1 of 9 and 2 of 25, respectively), more often to types 11A and 14 (2 of 8 and 3 of 8) and relatively frequently to type 23F (8 of 18). However, the convalescent antibody concentrations to type 23F were low and usually declined after the infection, whereas responders to 14 AOM had antibodies that persisted at a high concentration through the follow-up.
Conclusions:
The results emphasize the differences between Streptococcus pneumoniae serotypes in their immunogenicity and quantitative and qualitative differences of antibodies produced after infection.