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Bone Marrow-derived Macrophage Production
Published on: November 22, 2013
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Differential macrophage immune checkpoint expression triggered by bovine-associated staphylococci
Sarah Antonieta de Oliveira Veríssimo1, Filipe Aguera Pinheiro2, Ygor Fagundes Ruas3
1Departamento de Tecnologia e Inspeção de Produtos de Origem Animal, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil.
Veterinary Immunology and Immunopathology
|November 22, 2025
Summary
Bovine staphylococci strains modulate macrophage PD-1 expression differently. Some strains increase PD-1, while others decrease it over time, suggesting niche-specific immune responses and potential non-antibiotic treatments for intramammary infections.
Area of Science:
- Immunology
- Microbiology
- Veterinary Science
Background:
- Staphylococci are common causes of bovine intramammary infections (IMIs).
- Macrophage immune responses, including PD-1 and PD-L1 expression, are crucial in managing bacterial infections.
- Understanding how specific staphylococcal strains interact with macrophages is vital for developing new treatment strategies.
Purpose of the Study:
- To investigate the differential effects of bovine-associated staphylococcal strains on PD-1 and PD-L1 expression in macrophages.
- To explore strain- and niche-specific immune modulation by Staphylococcus aureus and Staphylococcus chromogenes.
- To assess the potential of targeting PD-1/PD-L1 pathways as a non-antibiotic approach for bovine IMIs.
Main Methods:
- Utilized RAW 264.7 murine macrophage cell line.
- Infected macrophages with four distinct bovine-associated staphylococci strains (S. aureus SN, S. aureus IM, S. chromogenes IM, S. chromogenes TA).
- Measured PD-1 and PD-L1 expression using flow cytometry at varying multiplicities of infection (MOI) and time points up to 6 hours.
Main Results:
- All staphylococcal strains significantly increased PD-1 expression in macrophages compared to controls, with effects being MOI-dependent.
- Staphylococcus aureus SN induced a marked increase in PD-1 expression over time.
- PD-1 expression decreased over time with IM strains, while S. chromogenes TA showed no significant change.
- Subtle but significant increases in PD-L1 expression were observed with S. aureus IM and S. chromogenes IM, particularly early in infection.
Conclusions:
- Bovine staphylococci exhibit strain- and niche-specific patterns in modulating macrophage PD-1 and PD-L1 expression.
- The findings suggest potential for PD-1/PD-L1 blockade as a non-antibiotic strategy against bovine IMIs.
- Further validation in primary bovine macrophages is necessary to confirm these results and therapeutic potential.
