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Phagocytic activity mediated via Fc gamma R, Fc mu R, and CR3 and H2O2 release during ontogeny of mouse macrophages
N Starobinas1, M Pereira, M E Summa
1Departamento de Imunologiá, Universidade de São Paulo, Brazil.
Abstract:
Mouse macrophage phagocytic activity was studied during ontogenetic development by comparing the abilities of infant and adult mouse macrophages to ingest opsonized particles via Fc gamma R, Fc mu R, or CR3. These studies were performed on resident, BCG-, and thioglycollate-stimulated peritoneal macrophages. The percent of ingestion and the index of maximal phagocytosis mediated via Fc gamma R is lower in infant than in adult mouse macrophages. However, the adherence mediated by Fc gamma R is similar to that seen with adult cells. Similar results were obtained when phagocytosis was mediated via Fc mu R or CR3, reaching adult levels during ontogenetic development. We also studied the age-dependent release of H2O2 by peritoneal cells before and after incubation with phorbol myristate acetate. Interestingly, the capacity of peritoneal cells from infant animals to generate H2O2 after BCG infection is similar to that observed in adult mice. Our results suggest that the adherence and phagocytosis mediated by Fc gamma R, although at lower levels than in adults, and the production of microbicidal H2O2 may be relevant for mouse survival during the first days of life.
Insights
Infant mouse macrophages show reduced phagocytosis but similar adherence via Fc gamma R compared to adults. However, microbicidal hydrogen peroxide production is comparable, suggesting its importance for early-life survival.
Area of Science:
- Immunology
- Developmental Biology
Background:
- Macrophage function is critical for host defense.
- Immune system maturation during ontogeny is essential for survival.
Purpose of the Study:
- To investigate age-dependent differences in mouse macrophage phagocytic activity.
- To compare the function of infant and adult mouse macrophages in particle ingestion and H2O2 release.
Main Methods:
- Assessed phagocytosis and adherence of opsonized particles by peritoneal macrophages from infant and adult mice via Fc gamma R, Fc mu R, and CR3.
- Measured hydrogen peroxide (H2O2) release from peritoneal cells before and after stimulation.
Main Results:
- Infant macrophages exhibited lower ingestion and maximal phagocytosis via Fc gamma R, but similar adherence, compared to adults.
- Phagocytosis mediated by Fc mu R and CR3 reached adult levels during ontogenetic development.
- Infant mice infected with BCG showed H2O2 production capacity similar to adult mice.
Conclusions:
- Despite lower phagocytosis, Fc gamma R-mediated functions and H2O2 production in infant macrophages may be vital for early-life survival.
- Ontogenetic development leads to increased macrophage phagocytic efficiency, with some functions maturing earlier than others.