Related Experiment Videos
Invasion and destruction of mucosal plasma cells by Tropheryma whippelii
Abstract:
Whipple's disease is a poorly understood systemic disorder associated with the bacillus, Tropheryma whippelii. An early stage of Whipple's disease is studied by using electron microscopy (ELMI) and immunohistochemistry. The diagnosis was confirmed by polymerase chain reaction-amplification and sequencing of the 16S ribosomal-RNA of the bacterium. By using ELMI, Tropheryma whippelii was found in plasma cells and macrophages in the jejunal mucosa. The immunoglobulin (Ig)A-positive plasma cells were focally destructed and their number significantly reduced. However, the bacilli in the plasma cells were morphologically intact. In contrast, the macrophages showed no signs of cell destruction, but contained bacilli in various stages of disintegration. A cytopathic effect of Tropheryma whippelii to IgA plasma cells may be the reason for the commonly found plasma cell reduction in the small intestine mucosa and an important pathogenic mechanism contributing to the evasion of the bacilli from local immune response.
Insights
Tropheryma whippelii causes Whipple's disease, damaging IgA plasma cells in the small intestine. This damage may explain reduced plasma cells and bacterial immune evasion.
Area of Science:
- Microbiology
- Immunology
- Gastroenterology
Background:
- Whipple's disease is a rare systemic infection caused by Tropheryma whippelii.
- The pathogenesis and early disease mechanisms remain poorly understood.
- Understanding early interactions between the bacterium and host cells is crucial.
Observation:
- Electron microscopy and immunohistochemistry were used to study jejunal mucosa in early Whipple's disease.
- Tropheryma whippelii was identified within plasma cells and macrophages.
Findings:
- Immunoglobulin A (IgA)-positive plasma cells showed focal destruction and reduced numbers, with intact bacteria.
- Macrophages contained disintegrating bacteria, indicating a different host response.
- Polymerase chain reaction confirmed the presence of Tropheryma whippelii via 16S ribosomal RNA sequencing.
Implications:
- Tropheryma whippelii may exert a cytopathic effect on IgA plasma cells, explaining reduced plasma cell counts in the small intestine.
- This interaction could be a key mechanism for bacterial evasion of the local immune response.