Ultrastructural changes and antigen localization in tissues from foot-and-mouth disease virus-infected guinea-pigs
Abstract:
Foot-and-mouth disease virus (FMDV)-induced ultrastructural changes in guinea-pig tongue, heelpad, mammary and liver tissues were examined using scanning and transmission electron microscopy. FMDV infection caused cell rounding and the release of virus in membrane limited vesicles in the animal tissues similar to that seen in other work in cell cultures. Microfilaments were present which may be responsible for cell rounding. Immunoperoxidase labeling revealed the attachment of the virus-infection associated (VIA) antigen to the smooth vacuoles of mammary and liver tissues, and to milk fat globules. The electron microscope immunoperoxidase procedure increased the sensitivity of detection sufficiently to allow the visualization of VIA antigen in tissues not previously shown to have the antigen. It is postulated that the release of the smooth vacuoles from the liver cells stimulates the animal's immune response to the VIA antigen.
Insights
Foot-and-mouth disease virus (FMDV) causes cell changes and releases viruses in guinea pig tissues. New methods visualize the virus-infection associated (VIA) antigen, potentially stimulating immune responses.
Area of Science:
- Veterinary Pathology
- Virology
- Immunology
Background:
- Foot-and-mouth disease virus (FMDV) causes significant economic losses in livestock.
- Understanding FMDV's cellular effects and antigen distribution is crucial for disease control.
- Previous studies focused on cell cultures, limiting understanding of in-vivo tissue changes.
Purpose of the Study:
- To investigate FMDV-induced ultrastructural changes in various guinea pig tissues.
- To identify the location and distribution of the virus-infection associated (VIA) antigen in infected tissues.
- To evaluate the utility of enhanced electron microscopy techniques for antigen detection.
Main Methods:
- Scanning and transmission electron microscopy were used to examine infected guinea pig tissues (tongue, heelpad, mammary, liver).
- Immunoperoxidase labeling combined with electron microscopy visualized the VIA antigen.
- Cellular changes like rounding and virus release in vesicles were documented.
Main Results:
- FMDV infection induced cell rounding and virus release within membrane-limited vesicles in all examined tissues.
- Microfilaments potentially contributing to cell rounding were observed.
- VIA antigen was detected attached to smooth vacuoles in mammary and liver tissues, and on milk fat globules.
- Enhanced electron microscopy revealed VIA antigen in tissues not previously identified.
Conclusions:
- FMDV infection causes characteristic ultrastructural changes in multiple host tissues.
- The enhanced immunoperoxidase technique significantly improves VIA antigen detection sensitivity in tissues.
- The release of smooth vacuoles from liver cells may trigger an immune response to the VIA antigen.
