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Polyomavirus persists in CD4/8 double-knockout, but not in CD4 or CD8 single-knockout mice
1Department of Clinical Virology, Karolinska Institute, Huddinge University Hospital, Sweden.
Virology
|September 10, 1995
Summary
Incomplete immunity in mice allows polyomavirus persistence. Severe immune deficiency, but not later immunosuppression or reinfection, led to prolonged viral presence.
Area of Science:
- Immunology
- Virology
- Molecular Biology
Background:
- Polyomavirus can persist in hosts, but the role of immunocompetence in viral persistence and reactivation remains incompletely understood.
- Investigating viral persistence in immunocompromised models is crucial for understanding host-pathogen dynamics.
Purpose of the Study:
- To investigate the impact of varying degrees of immunocompetence on polyomavirus persistence and reactivation in adult mice.
- To determine if later immunosuppression or secondary infection can trigger viral reactivation in previously infected mice.
Main Methods:
- Polyomavirus-specific polymerase chain reaction (PCR) was used to detect viral DNA in various organs of mice.
- Studies were conducted on normal adult mice, CD4-/- and CD8-/- single-knockout mice, CD4-/-8-/- double-knockout mice, and mice immunosuppressed via thymectomy (THX), cytosine-beta-D-arabinofuranoside (Ara-C) treatment, or total body irradiation (TBI).
- Viral DNA was monitored from 4 days to 2 months postinfection (p.i.), with additional studies on later immunosuppression and secondary polyomavirus challenge.
Main Results:
- Primary polyomavirus infection in CD4-/- or CD8-/- single-knockout mice showed transient viral DNA detection, similar to normal mice, with clearance by 1-2 months p.i.
- In contrast, CD4-/-8-/- double-knockout mice and mice immunosuppressed by THX, Ara-C, or TBI exhibited polyomavirus detection in most organs, persisting for 1-2 months p.i.
- Later immunosuppression in normal adult mice did not induce viral reactivation, and a second polyomavirus challenge did not result in detectable viral DNA in either normal or recently immunosuppressed mice.
Conclusions:
- Severe deficiencies in both CD4 and CD8 T-cell responses, or significant general immunosuppression, are critical for polyomavirus persistence in adult mice.
- Transient immunocompetence impairment or secondary exposure does not appear to lead to polyomavirus reactivation or prolonged persistence.