Antibody in Middle Ear Fluid of Children Originates Predominantly from Sera and Nasopharyngeal Secretions

Abstract

The human middle ear is devoid of any immunocompetent cells in normal mucosa. We sought to determine the source of antibody present in the middle ear of children. Total IgG, IgA, and secretory IgA antibodies were determined by enzyme-linked immunosorbent assay from the nasopharyngeal, middle ear, and serum samples of children with acute otitis media. The two-dimensional gel electrophoresis pattern of the entire array of IgA antibodies in the nasal wash (NW) and middle ear fluid (MEF) was compared from the MEF and NW samples using isoelectric focusing and Western blotting. C olonization of the nasopharynx (NP) by respiratory bacterial pathogens produces both a systemic and a mucosal immune response (1,10,11,15,22,26,38). Local mucosal immunity in the NP plays a crucial role in the reduction of carriage and prevention of local disease (acute otitis media [AOM], sinusitis, and pneumonia) and systemic invasion by respiratory bacteria (4, 16, 20-22, 27, 36). Protective mucosal immune responses are most effectively induced by mucosal immunization through oral and nasal routes but the vast majority of vaccines in use today are administered by injection (19). Parenteral administration of Haemophilus influenzae type b and Streptococcus pneumoniae polysaccharide and polysaccharide-conjugate vaccines can induce a transient mucosal immune response but immunologic memory at the mucosal level is generally not induced (23,24,37).Current pneumococcal conjugate vaccines for prevention of AOM and pneumonia are administered by injection and are considered to be effective by generation of antibody in serum and transudation of antibody to the NP, middle ear, and lung (3,12,25,34,37). New vaccines for the prevention of Streptococcus pneumoniae and nontypeable Haemophilus influenzae AOM and other mucosal infections are in development (2, 6, 11, 21, 22). Therefore, the sources of antibody at the site of infection (the middle ear) need to be understood.Although the normal mucosa of the middle ear possesses neither immunocompetent lymphocytes nor associated lymphoid tissues, there are studies which have demonstrated the presence of secretory IgA (sIgA) in middle ear effusions and IgA plasma cells in the mucosa of the middle ear suggesting that a local immune response in the middle ear is possible and may contribute to resolution of or protection from infection (8,9,18). Previous studies have also shown severalfold more IgG antibody compared to IgA antibody in the middle ear, suggesting that antibodies in the middle ear arrive by transudation from serum (33). In the present study, we evaluated (i) simultaneous concentrations of IgG and IgA in serum, NW, and MEF samples in children with AOM; (ii) simultaneous concentrations of sIgA in NW and MEF samples; and (iii) the electrophoresis pattern of the entire array of IgA antibodies in the MEF and NW to determine whether the antibodies present in middle ear fluid were predominantly derived from serum and the nasal passageways by reflux up the Eustachian tube. MATERIALS AND METHODSPatient popul...

Divergent mucosal and systemic responses in children in response to acute otitis media

“…The NP mucosal compartment cytokine levels diverged from the responses in the peripheral blood, but were similar to those in the middle ear. These data are consistent with our earlier report [16] that MEF contains predominantly secretions from the NP, and suggests limited migration of immune cells or transudation of immune effectors from blood. IL-2 production plays a significant role in driving inflammatory responses during experimental AOM infection of animal models [28][29][30].…”

Cellular Immune Response in Young Children Accounts for Recurrent Acute Otitis Media

“…Conversely, our hypothesis is that otopathogen-specific T-cell memory, if generated, primarily is effective in immune protection by activity in the nasopharynx and the Eustachian tube, with most cells originating from regional lymph nodes, i.e., the tonsils and adenoids. In support of that notion we have shown that the antibody present in middle ear fluid predominantly, if not exclusively, derives from the serum by transudation and reflux of antibody produced in the nasopharynx that reaches the middle ear by way of the Eustachian tube[28] and that MEF of children with AOM is largely devoid of lymphocytes (unpublished).…”

“…T-, B- cells, macrophages, dendritic cells and natural killer (NK) cells) and antibodies into the MEF and middle ear mucosa after the onset of AOM [28, 53, 55, 56]. T-cells were described as dominant among the lymphocytes in the MEF during AOM, with CD4 + CD45RO + memory T-cells predominating[53].…”

Middle Ear and Eustachian Tube Mucosal Immunology

“…Another study reported that the IgG:IgA ratio in MEF resembled that observed in serum but that small amounts of SIgA were also detected (Kaur et al, 2012).…”