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Updated: Aug 19, 2025
Separation of Immune Cell Subpopulations in Peripheral Blood Samples from Children with Infectious Mononucleosis
Published on: September 7, 2022
PD-L1 is upregulated in CD163+ tonsillar macrophages from children undergoing EBV primary infection
Agustina Moyano1, Natalia Ferressini1, Elena De Matteo1,2
1Molecular Biology Laboratory, Multidisciplinary Institute for Investigation in Pediatric Pathologies (IMIPP), Pathology Division, CONICET-GCBA, Ricardo Gutiérrez Children's Hospital, Buenos Aires, Argentina.
Abstract:
Epstein-Barr Virus (EBV) is a tumor associated virus that modulates not only the infected cells but also innate and adaptive immunity. Macrophages play a key role in tumor development and progression. Particularly, the M2 phenotype (CD163) with anti-inflammatory activity contributes to a favorable microenvironment for tumor development while the M1 (CD68) proinflammatory phenotype contributes to a restrictive one. In the context of pediatric EBV infection, little is known about macrophage contribution to PD-L1 expression, a molecule involved in immune exhaustion. We studied tonsils of primary infected (PI), healthy carriers (HC), reactivated (R), and not infected (NI) pediatric patients. Positive correlations were demonstrated for CD68+PD-L1+ in R and for CD163+PD-L1+ only in PI. Furthermore, CD163+PD-L1+ cell numbers were higher than PD-L1+CD68+ in PI patients. In addition, a positive correlation between PD-L1+CD163+ cells and LMP1 viral latent protein was observed in PI patients, and a positive correlation between PD-L1+CD68+ cells and BMRF1 lytic antigen was demonstrated. A positive correlation between TGF-β and PD-L1 expression was demonstrated in HC patients. Our findings indicate that EBV's lytic and latent antigens might be regulating macrophages' PD-L1 expression, particularly in PI patients, whereas, surprisingly, only TGF-β could be related to total PD-L1 upregulation. Given the relevance of macrophages and the PD-1/PD-L1 pathway in tumor progression and survival, more studies in early EBV infection could help to develop EBV-associated tumor therapies.
Insights
Epstein-Barr Virus (EBV) infection in children influences macrophage PD-L1 expression, a key molecule in immune exhaustion. EBV antigens correlate with PD-L1 on specific macrophage types, suggesting a role in tumor development.
Area of Science:
- Immunology
- Virology
- Oncology
Background:
- Epstein-Barr Virus (EBV) is a tumor-associated virus impacting host immunity.
- Macrophages, particularly M1 (CD68) and M2 (CD163) phenotypes, play critical roles in tumor microenvironments.
- The role of macrophage PD-L1 expression in pediatric EBV infection remains largely unexplored.
Purpose of the Study:
- To investigate the association between macrophage phenotypes (M1/CD68, M2/CD163) and PD-L1 expression in pediatric patients with primary EBV infection (PI), reactivation (R), and healthy carriers (HC).
- To explore the correlation between EBV latent (LMP1) and lytic (BMRF1) antigens and macrophage PD-L1 expression.
- To examine the relationship between TGF-β and PD-L1 expression in EBV-infected pediatric tonsils.
Main Methods:
- Analysis of tonsil tissues from pediatric patients across different EBV infection statuses: primary infected (PI), healthy carriers (HC), reactivated (R), and not infected (NI).
- Immunohistochemical staining to identify and quantify CD68+, CD163+, and PD-L1+ cells.
- Statistical analysis to determine correlations between macrophage markers, PD-L1, EBV antigens (LMP1, BMRF1), and TGF-β.
Main Results:
- Positive correlation between CD68+ cells and PD-L1+ in reactivated (R) patients.
- Significant correlation between CD163+ cells and PD-L1+ in primary infected (PI) patients, with higher CD163+PD-L1+ than PD-L1+CD68+ cells.
- Correlation of PD-L1+CD163+ cells with EBV latent protein LMP1 in PI patients.
- Correlation of PD-L1+CD68+ cells with EBV lytic antigen BMRF1.
- Positive correlation between TGF-β and PD-L1 expression observed in healthy carriers (HC).
Conclusions:
- EBV lytic and latent antigens may regulate macrophage PD-L1 expression, particularly in primary infection.
- TGF-β is linked to overall PD-L1 upregulation in healthy carriers.
- Understanding macrophage PD-L1 dynamics in early EBV infection is crucial for developing therapies against EBV-associated tumors.
