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Updated: May 20, 2026
Merkel Cell Polyomavirus Infection and Detection
Published on: February 7, 2019
Molecular diagnosis of a laboratory mouse papillomavirus (MusPV)
Joongho Joh1, A Bennett Jenson, Mary Proctor
1Department of Medicine, James Graham Brown Cancer Center (JGBCC), USA.
Abstract:
MusPV, a novel papillomavirus (PV) that naturally infects laboratory mice, was isolated and characterized from a colony of NMRI-Foxn1(nu)/Foxn1(nu) (nude) mice in India. Because MusPV may have been missed during routine pathogen screening of mice in colonies worldwide, a variety of detection methods are described to detect MusPV. The clinical and histologic lesions of productive MusPV infections fit PV-associated features, including papillomas, koilocytes within the stratum granulosum of the hyperplastic/acanthotic papillomatous epithelium, and the presence of intranuclear virus particles in koilocytotic cells visualized by electron microscopy. Antiserum against disrupted PV virions, isolated from another species (canine), identified conserved viral antigens in productively infected cells by immunohistochemistry. A rolling circle technique was used to amplify viral circular DNAs followed by endonuclease restriction enzyme digestion to determine the correct size of PV DNA. Consensus PV degenerative primers, My09/11, commonly used to detect many different types of PVs by polymerase chain reaction (PCR), particularly mucosotropic HPVs, also identified MusPV and all rodent PVs tested. Since there was one nucleotide mismatch between the My09/11 primer set and the MusPV template, a new primer set, MusPV-My09/11, was designed to specifically detect MusPV in latent infections and spontaneous MusPV-induced papillomas. Southern blot analysis verified the presence of full size PV DNA in infected tissues. Virus-like particles (VLPs), generated from MusPV L1 genes, provided a substrate for serological testing of naturally and experimentally infected mice. In summary, a series of diagnostic assays were developed and validated to detect MusPV infection in skin tumors and serological response in laboratory mice.
Insights
A novel mouse papillomavirus (MusPV) was identified in laboratory mice. This study details diagnostic methods to detect MusPV infections and serological responses in mice, crucial for research settings.
Area of Science:
- Veterinary Virology
- Oncology
- Molecular Biology
Background:
- A novel papillomavirus, MusPV, has been identified in laboratory mice.
- This virus may evade standard pathogen screening protocols in mouse colonies globally.
- Understanding MusPV is critical for maintaining the health of research animal populations.
Purpose of the Study:
- To characterize MusPV and develop reliable diagnostic assays for its detection.
- To establish methods for identifying both active MusPV infections and immune responses in mice.
- To ensure accurate screening of laboratory mice for MusPV to prevent research interference.
Main Methods:
- Isolation and characterization of MusPV from infected nude mice.
- Histopathological examination of lesions, including koilocytosis and electron microscopy for viral particles.
- Immunohistochemistry using canine PV antiserum to detect viral antigens.
- Rolling circle amplification and endonuclease digestion for viral DNA analysis.
- Polymerase chain reaction (PCR) using degenerate and specific primer sets (My09/11 and MusPV-My09/11).
- Southern blot analysis to confirm viral DNA presence.
- Generation of virus-like particles (VLPs) for serological assays.
Main Results:
- MusPV infections present with characteristic papillomas and histological features of papillomavirus infection.
- Conserved PV antigens were detected in infected cells.
- Both degenerate (My09/11) and a newly designed specific primer set (MusPV-My09/11) successfully detected MusPV DNA.
- Southern blot confirmed the presence of full-length PV DNA.
- VLPs were successfully generated for serological testing, enabling detection of immune responses.
Conclusions:
- A comprehensive suite of diagnostic assays has been developed and validated for MusPV.
- These methods can detect MusPV in skin tumors and assess serological responses in laboratory mice.
- The developed assays are essential for accurate screening and management of MusPV in research settings.
