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Nonviral microbodies with viral antigenicity produced in cytomegalovirus-infected cells
Abstract:
Masses of homogeneous electron-dense material accumulate in the cytoplasmic inclusions of cultured fibroblasts which have been infected with "wild" and "adapted" strains of human cytomegalovirus. The substance appears to be produced by microtubular membranes and the Golgi apparatus; ultrastructural histochemistry suggests that it is not lysosomal in nature nor is it comprised of lipids or polysaccharides. The dense material "buds" into cytoplasmic tubules forming circumscribed bodies having an investing membrane similar to the viral envelope. After transport to the extracellular milieu in cytoplasmic tubules and vesicles, virions and dense bodies can be demonstrated by immune electron microscopy. The homogeneous dense body appears to be a unique product of the cytomegalovirus-infected cell which possesses a limiting membrane having antigenic determinants common with the viral envelope.
Insights
Human cytomegalovirus infection causes unique dense bodies to form in cells. These bodies, originating from cellular structures, share a membrane with the virus.
Area of Science:
- Cell biology
- Virology
- Microscopy
Background:
- Human cytomegalovirus (HCMV) is a common pathogen.
- HCMV infection can lead to various clinical manifestations.
- Understanding HCMV-induced cellular changes is crucial for disease management.
Purpose of the Study:
- To characterize the nature and origin of electron-dense inclusions in HCMV-infected fibroblasts.
- To investigate the relationship between these inclusions and HCMV virions.
Main Methods:
- Cultured human fibroblasts infected with HCMV.
- Ultrastructural analysis using electron microscopy.
- Ultrastructural histochemistry.
- Immune electron microscopy.
Main Results:
- Homogeneous electron-dense material accumulates in cytoplasmic inclusions of infected fibroblasts.
- This material originates from microtubular membranes and the Golgi apparatus.
- The dense material forms circumscribed bodies with a membrane similar to the viral envelope.
- Virions and dense bodies are found extracellularly, transported via cytoplasmic tubules and vesicles.
- Immune electron microscopy confirms antigenic similarities between the dense body membrane and the viral envelope.
Conclusions:
- A unique dense body is produced by HCMV-infected cells.
- This dense body shares antigenic determinants with the HCMV envelope.
- The dense body is likely involved in the HCMV replication or egress cycle.