Local production of IgG to pneumococcal C-polysaccharide in upper airway secretions from children with recurrent acute otitis media

The Adenoids but Not the Palatine Tonsils Serve as a Reservoir for Bacteria Associated with Secretory Otitis Media in Small Children

Our findings that the microbiome differs between crypts of the adenoids and crypts of the palatine tonsils, including the relative abundances of potential pathogens such as Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis, may be the stepping stone for further investigation of individual microbiomes in a longitudinal design that includes recording of the fluctuating health status of the child. Such studies may have the potential to lead to new preventive measurements such as implantation of protective nonpathogens at the nasopharynx as an alternative to adenoidectomy.

Acute otitis media (AOM), secretory otitis media (SOM), and acute pharyngotonsillitis are the most frequent reasons for visits to general practitioners, pediatricians, and otolaryngologists. Microbial colonization of the epithelial lining of Waldeyer’s lymphatic tissues, consisting of the palatine tonsils, lingual tonsils, adenoids, and Eustachian tube tonsil, is a well-known clinical challenge during infancy due to frequent episodes of upper respiratory tract infections. However, no previous studies have investigated the combined role of the palatine tonsils and the adenoids as a reservoir for pathogens associated with SOM in small children. We analyzed the combined crypt microbiome of the palatine tonsils and adenoids from 14 small children with hyperplasia of the tonsils or adenoids and 14 small children with SOM using 16S rRNA gene pyrosequencing. Our study demonstrated a significant difference between the microbiome of the adenoids and that of the palatine tonsils in the two groups but not between the two anatomical locations within the two groups. In particular, the potential pathogens Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis were almost exclusively found in the adenoids of both patient groups, indicating that the adenoids and not the palatine tonsils are the main reservoir for potential pathogens leading to AOM and SOM.

IMPORTANCE Our findings that the microbiome differs between crypts of the adenoids and crypts of the palatine tonsils, including the relative abundances of potential pathogens such as Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis, may be the stepping stone for further investigation of individual microbiomes in a longitudinal design that includes recording of the fluctuating health status of the child. Such studies may have the potential to lead to new preventive measurements such as implantation of protective nonpathogens at the nasopharynx as an alternative to adenoidectomy.

IgG subclass profiles in normal human sera of antibodies specific to five kinds of microbial antigens

The levels of subclass-specific immunoglobulin G (IgG) antibodies to five microbial antigens in normal human sera were measured by enzyme-linked immunosorbent assays (ELISA). The aim was to compare the IgG subclass profiles of specific antibodies to diverse antigens originating from virus, intra- and extracellular bacteria. Serum samples from 162 Danish women were analyzed for IgG1, IgG2, IgG3, and IgG4 antibodies against a peptide of the major outer membrane protein (MOMP) of Chlamydia trachomatis, the native outer membrane proteins of Chlamydia pneumoniae, recombinant membrane proteins of Mycoplasma pneumoniae, recombinant parvovirus B19 capsomers (VP1 and VP2) and C-polysaccharide of Streptococcus pneumoniae (pneumococcus). Antibodies specific for viral and bacterial protein antigens belonged mainly to the subclasses IgG1 and IgG3 while the antibody profile specific for pneumococcal C-polysaccharide was dominated by the subclass IgG2. Antibodies to virus, intra- and extracellular bacteria entering the body via the respiratory tract were found primarily to elicit an IgG1 response. In contrast, antibodies specific for MOMP from C. trachomatis, which infects the urogenital tract, were predominantly IgG3. Our results show that the nature of the antigen and/or the site of colonization or infection have impact on which type of IgG subclass a microorganism elicits.

Mucosal Immunity and Bacteriology of the Eustachian Tube

The pathogenesis of otitis media is a multifaceted process that is not completely understood. Eustachian tube dysfunction plays a central but uncertain role, as do viral and bacterial microorganisms. Of the latter, the three most important are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. This article reviews the various mechanisms of infection and the immune system's response to them.

Pneumococcal antigens and serum antibody responses in experimentally induced sinusitis

Maxillary sinusitis was induced in New Zealand White rabbits with Streptococcus pneumoniae serotype 3 and the serum antibody response was recorded by enzyme immunoassay. Activity of the three major immunoglobulin classes, viz. IgG, IgA and IgM, against the type-specific capsular polysaccharide, the cell wall C-polysaccharide as well as its subunit phosphorylcholine was analyzed. A pronounced increase in immunoglobulins reactive to the specific capsular antigen was observed throughout the study period, with the rise being particularly noticeable during the first 2 weeks. An increase in anti-C-polysaccharide antibodies was also evident, but no reaction to phosphorylcholine could be detected. Although the histological findings at 3 and 4 weeks varied in spite of similar serum antibody responses, a correlation appeared to exist between a more rapidly increasing anti-capsular IgG production and the prevalence of a purulent sinus secretion.