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Published on: August 1, 2012
Functional changes of macrophages induced by dimeric glycosaminylmuramyl pentapeptide
Anna Ilinskaya1, Natalia Oliferuk, Valerii Livov
1National Research Center Institute of Immunology, Russian Federal Medical Biological Agency, Moscow, Russia.
Abstract:
Under the influence of dimeric glucosaminylmuramyl pentapeptide (diGMPP), a component of bacterial cell wall, macrophages undergo certain changes similar to those associated with dendritic cell (DC) maturation. The effect of diGMPP on DCs resulted in maturation and expression of CD83. Macrophages treated with diGMPP displayed reduced phagocytic activity and elevated ability to kill ingested bacteria. Reduced phagocytosis may be due to phenotypic changes that occur in macrophages during the maturation process, such as reduced expression of receptors that mediate ingesting of microorganisms (CD16, CD64, and CD11b). Down-regulated expression of pattern-recognizing receptors (TLR2, TLR4, and CD206) was accompanied by elevated expression of antigen-presenting (HLA-DR) and costimulating molecules (CD86 and CD40), similar to alterations observed in maturating DCs. In addition, diGMPP treatment of macrophages resulted in enhanced synthesis of IL-12, TNF-alpha, and IL-1beta.
Insights
Bacterial cell wall component, dimeric glucosaminylmuramyl pentapeptide (diGMPP), induces macrophage maturation, enhancing their ability to kill bacteria while reducing phagocytosis. This process involves changes in cell surface molecule expression and increased cytokine production.
Area of Science:
- Immunology
- Cell Biology
Background:
- Macrophages and dendritic cells (DCs) are crucial immune cells.
- Bacterial components can modulate immune cell function.
Purpose of the Study:
- To investigate the effects of dimeric glucosaminylmuramyl pentapeptide (diGMPP) on macrophage maturation and function.
- To compare diGMPP-induced changes in macrophages to DC maturation.
Main Methods:
- Macrophages were treated with diGMPP.
- Phenotypic changes were assessed by analyzing cell surface marker expression (e.g., CD83, CD16, CD64, CD11b, TLR2, TLR4, CD206, HLA-DR, CD86, CD40).
- Phagocytic activity and bacterial killing were measured.
- Cytokine synthesis (IL-12, TNF-alpha, IL-1beta) was analyzed.
Main Results:
- diGMPP induced maturation in macrophages, characterized by CD83 expression, similar to DCs.
- Macrophages showed reduced phagocytic activity but enhanced bacterial killing.
- Expression of phagocytic receptors (CD16, CD64, CD11b) and pattern-recognizing receptors (TLR2, TLR4, CD206) decreased.
- Expression of antigen-presenting (HLA-DR) and costimulatory molecules (CD86, CD40) increased.
- diGMPP treatment elevated the synthesis of IL-12, TNF-alpha, and IL-1beta.
Conclusions:
- diGMPP acts as a maturation factor for macrophages, mimicking some aspects of DC maturation.
- Macrophage functional reprogramming involves a trade-off between phagocytosis and pathogen killing.
- These findings highlight diGMPP's potential role in modulating innate and adaptive immune responses.
