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Serum antibody response to Moraxella catarrhalis proteins in stringently defined otitis prone children
Dabin Ren1, Anthony L Almudevar2, Timothy F Murphy3
1Rochester General Hospital Research Institute, Rochester, NY 14621, USA.
Background:
Moraxella catarrhalis (Mcat) is a frequent pathogen of acute otitis media (AOM) in young children. Here we prospectively assessed naturally-induced serum antibodies to four Mcat vaccine candidate proteins in stringently defined otitis prone (sOP) and non-otitis prone (NOP) children age 6-36months old following nasopharyngeal (NP) colonization, at onset of AOM and convalescence from AOM.
Methods:
Serum IgG and IgM antibody against recombinant Mcat proteins, oligopeptide permease A (OppA), outer membrane protein (OMP) CD, hemagglutinin (Hag), and PilA clade 2 (PilA2), were quantitated by ELISA.
Results:
During NP colonization by Mcat all four antigens were immunogenic in both sOP and NOP children. However, sOP children had lower antibody responses than NOP children across age 6-36months, similar to our findings for protein vaccine candidates of Streptococcus pneumoniae (Spn) and Nontypeable Haemophilus influenzae (NTHi). sOP children displayed a later and lower peak of antibody rise than NOP children for all four antigens during NP colonization of Mcat. The age-dependent increase of antibody ranked as OppA>Hag5-9>OMP CD>PilA2 in both sOP and NOP children. Lower serum antibody levels to the Mcat antigens were measured in sOP compared to NOP children at the onset of AOM. We did not find a consistent significant increase of antibody at the convalescence phase after an AOM event.
Conclusions:
sOP children is a highly vulnerable population that mount lower serum antibody responses to Mcat candidate vaccine proteins compared to NOP children during asymptomatic NP carriage and at onset of AOM.
Insights
Children prone to otitis media (sOP) show weaker antibody responses to Moraxella catarrhalis (Mcat) vaccine candidates compared to non-otitis prone (NOP) children. This reduced immunity is observed during colonization and at the onset of acute otitis media (AOM).
Area of Science:
- Immunology
- Pediatrics
- Vaccinology
Background:
- Moraxella catarrhalis (Mcat) is a primary cause of acute otitis media (AOM) in young children.
- Understanding immune responses to Mcat is crucial for developing effective vaccines.
- Otitis-prone (OP) children exhibit distinct immune profiles compared to non-otitis-prone (NOP) children.
Purpose of the Study:
- To prospectively assess naturally induced serum antibodies against four Mcat vaccine candidate proteins.
- To compare antibody responses in stringently defined otitis-prone (sOP) and non-otitis-prone (NOP) children.
- To evaluate antibody levels following nasopharyngeal colonization, AOM onset, and convalescence.
Main Methods:
- Quantification of serum IgG and IgM antibodies against recombinant Mcat proteins (OppA, OMP CD, Hag, PilA2) using ELISA.
- Prospective study design in children aged 6-36 months.
- Categorization of children into sOP and NOP groups based on defined criteria.
Main Results:
- All four Mcat antigens were immunogenic in both sOP and NOP children during nasopharyngeal colonization.
- sOP children exhibited lower and delayed antibody responses compared to NOP children across all antigens.
- Lower serum antibody levels to Mcat antigens were observed in sOP children at AOM onset; no consistent increase was noted during convalescence.
Conclusions:
- sOP children represent a vulnerable population with diminished serum antibody responses to Mcat vaccine candidates.
- These lower responses occur during asymptomatic nasopharyngeal carriage and at the onset of AOM.
- Findings highlight potential challenges in achieving protective immunity in sOP children via current vaccine strategies.
