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Published on: April 29, 2015
Activation of guinea pig peritoneal macrophages by ribosomal extract of Salmonella typhi strain. Electron microscopy
Abstract:
Normal macrophages and Salmonella typhi ribosomal antigen-activated (immune) ones were studied by electron microscopy. Examination of fine sections from samples incubated between 30 and 120 minutes at 37 degrees C, emphasized phagocytic ability of activated macrophages (29-69% activated macrophages phagocytized 3.7-5.6 bacteria/cell, in contrast to 23-43% with 2.6-4.4 bacteria/phagocytized by non-immune cells). The ultrastructural studies of activated macrophages, performed by electron microscopy, showed the following aspects: a) macrophages with pseudopodiform prolongations, presenting the tendency of bacterial sequestration: b) phagosomes with ingested virulent germs; c). bacteria presenting various degrees of wall and cytoplasm alterations; d). mitochondria with multiple cristae; e). cells with well developed Golgi apparatus and the presence of lysosomes in great numbers; f). existence of a space between the phagosome membrane and the bacterial wall. Experimental results demonstrated: I. an increased phagocytic activity of Salmonella typhi ribosomal antigen-activated macrophages and II. activation expressed as ultrastructural modifications at the level of immune macrophages and also of the bacteria phagocytized by them.
Insights
Salmonella typhi ribosomal antigen activates macrophages, significantly increasing their phagocytic activity and causing distinct ultrastructural changes in both the immune cells and the bacteria they engulf.
Area of Science:
- Immunology
- Microbiology
- Cell Biology
Background:
- Macrophages are crucial immune cells involved in phagocytosis.
- Salmonella typhi ribosomal antigen can modulate macrophage function.
Purpose of the Study:
- To investigate the effect of Salmonella typhi ribosomal antigen on macrophage phagocytic activity.
- To examine the ultrastructural changes in activated macrophages and phagocytized bacteria.
Main Methods:
- Electron microscopy was used to study normal and activated macrophages.
- Macrophages were incubated with Salmonella typhi ribosomal antigen.
- Phagocytic activity was quantified by counting bacteria per cell.
Main Results:
- Activated macrophages exhibited significantly higher phagocytic activity compared to normal macrophages.
- Ultrastructural analysis revealed pseudopod formation, phagosomes with bacteria, and alterations in bacterial cell walls.
- Activated macrophages showed enhanced Golgi apparatus, lysosomes, and mitochondrial changes.
Conclusions:
- Salmonella typhi ribosomal antigen enhances macrophage phagocytosis.
- Immune activation leads to observable ultrastructural modifications in macrophages and phagocytized bacteria.
