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Published on: September 7, 2018
Visualization of Molluscum Contagiosum Virus in FFPE Skin Sections Using NanoSuit-CLEM: Ultrastructural Evidence of
Yuri Sakano1, Hideya Kawasaki1
1NanoSuit Research Laboratory, Division of Preeminent Bioimaging Research, Institute of Photonics Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan.
Background:
Molluscum contagiosum (MC) is a common viral skin infection caused by members of the Poxviridae family. It primarily affects children, sexually active adults, and immunocompromised individuals. Although MC spreads through direct contact and auto-inoculation, the precise mechanisms by which the virus penetrates the skin barrier remain poorly understood.
Methods:
We applied NanoSuit-correlative light and electron microscopy (NanoSuit-CLEM) to formalin-fixed paraffin-embedded (FFPE) skin sections to visualize MC virus particles in situ with high resolution. Melan-A immunohistochemistry using 3,3'-diaminobenzidine (DAB) with osmium staining was performed to identify Henderson-Patterson bodies.
Results:
Ultrastructural analysis revealed that MC virus particles were densely localized in the stratum corneum but did not invade deeper epithelial layers in intact skin. However, in areas of epidermal disruption, such as detached or damaged stratum corneum, the virus was observed penetrating into lower layers. While Melan-A immunostaining successfully detected Henderson-Patterson bodies, it failed to identify mature MC virus particles. In contrast, NanoSuit-CLEM combined with Mayer's hematoxylin and lead staining enabled detailed visualization of mature viral particles and their distribution within the stratum corneum.
Conclusions:
These findings provide direct ultrastructural evidence that MC virus entry occurs through compromised skin, underscoring the crucial role of the stratum corneum in barrier function. This study highlights the importance of preventing mechanical skin injury, such as scratching or shaving, to limit MC transmission. NanoSuit-CLEM offers a powerful new tool for studying viral pathogenesis in archival tissue samples.
Insights
Molluscum contagiosum virus enters the skin through breaks in the stratum corneum, not intact skin. Preventing skin damage is key to limiting viral transmission.
Area of Science:
- Dermatology
- Virology
- Microscopy
Background:
- Molluscum contagiosum (MC) is a common Poxviridae viral skin infection.
- It affects children, sexually active adults, and immunocompromised individuals.
- MC transmission mechanisms, particularly skin penetration, are poorly understood.
Purpose of the Study:
- To visualize MC virus particles in situ using high-resolution microscopy.
- To elucidate the precise mechanisms of MC virus skin barrier penetration.
Main Methods:
- Applied NanoSuit-correlative light and electron microscopy (NanoSuit-CLEM) to FFPE skin sections.
- Utilized Melan-A immunohistochemistry for Henderson-Patterson body identification.
- Employed Mayer's hematoxylin and lead staining with NanoSuit-CLEM.
Main Results:
- MC virus particles were localized in the stratum corneum, not deeper layers of intact skin.
- Virus penetration occurred in areas of epidermal disruption.
- NanoSuit-CLEM visualized viral particles and distribution, unlike Melan-A staining.
Conclusions:
- MC virus enters the skin through compromised barrier function.
- The stratum corneum plays a critical role in skin barrier integrity.
- Preventing mechanical skin injury is vital for limiting MC transmission.
