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Published on: June 14, 2020
Peripheral blood antigen presenting cell responses in otitis-prone and non-otitis-prone infants
Naveen Surendran1, Ted Nicolosi1, Ravinder Kaur1
1Center for Infectious Diseases and Immunology, Rochester General Hospital Research Institute, Rochester Regional Health System, 1425 Portland Ave, Rochester, NY, USA.
Insights
Stringently defined otitis-prone (sOP) children have higher numbers of antigen-presenting cells (APCs), but their function and systemic innate immune responses are similar to non-otitis-prone infants. This suggests a potential persistent mucosal inflammatory status in sOP children.
Area of Science:
- Immunology
- Pediatrics
- Infectious Diseases
Background:
- Otitis-prone (OP) children, particularly stringently defined (sOP), exhibit immune dysfunctions, including impaired B-cell and T-cell memory responses.
- Previous research indicates potential immune system vulnerabilities in sOP children, necessitating further investigation into specific immune cell populations.
Purpose of the Study:
- To investigate potential defects in the numbers, phenotype, and function of professional antigen-presenting cells (APCs) in the peripheral blood of sOP infants.
- To compare APC characteristics between sOP infants and age-matched non-otitis-prone (NOP) infants.
Main Methods:
- Flow cytometry was used to determine APC phenotypic counts, MHC II expression, and intracellular cytokine levels following Toll-like receptor 7/8 (TLR7/8) stimulation.
- Reverse transcription-polymerase chain reaction (RT-PCR) was employed to measure innate immune mRNA expression.
- Luminex technology was utilized for cytokine quantification.
Main Results:
- sOP infants showed significantly higher phenotypic counts of monocytes and conventional dendritic cells compared to NOP infants (P < 0.05).
- No significant differences were observed in APC activation or function between the sOP and NOP groups.
- Expression levels of various Toll-like receptors (TLRs), intracellular signaling molecules, and downstream cytokines did not differ significantly between sOP and NOP infants.
Conclusions:
- The increased numbers of APCs in sOP infants may indicate a persistent mucosal inflammatory status.
- Systemic innate immune responses, as assessed by transcriptional and cytokine profiles of peripheral blood mononuclear cells (PBMCs), do not appear to differ between sOP and NOP infants.
Abstract:
Stringently defined otitis-prone (sOP) children represent a new classification of the otitis-prone condition. Previous studies showed dysfunction in Ab, B-cell memory and T-cell memory responses. We sought to determine whether there are defects in numbers, phenotype and/or function of professional APC in the peripheral blood of sOP infants. APC phenotypic counts, MHC II expression and intracellular cytokine levels were determined in response to TLR7/8 (R848) stimulation by flow cytometry. Innate immune mRNA expression was measured using RT-PCR and cytokines were measured using Luminex technology. Significant (P < 0.05) increases in the phenotypic counts of monocytes and conventional dendritic cells but not plasmacytoid DCs were observed in sOP compared with non-otitis-prone (NOP) age-matched infants. No significant differences in APC activation or function were observed. Expression of various TLRs, intracellular signaling molecules and downstream cytokines was also not found to be significantly different between sOP and NOP infants. Higher numbers of APCs in sOP infants suggest the possibility of a persistent mucosal inflammatory status. Transcriptional and cytokine profiles of PBMCs among sOP infants suggest their systemic innate responses are not different compared to NOP infants.
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