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Updated: Aug 15, 2026
A Rat Model of EcoHIV Brain Infection
Published on: January 21, 2021
Early pathological changes in the central nervous system of acutely feline-immunodeficiency-virus-infected cats
Andreas Hein1, Jean-Pierre Martin, Rüdiger Dörries
1Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Mannheim, Ruprecht-Karls-Universität Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
Abstract:
The animal model of feline immunodeficiency virus (FIV) infection of cats was used to dissect the pathogenic role of microglia within the first 6 months of infection. Applying real-time PCR, microglia-associated FIV replication was first detectable at 14 days past inoculation (dpi) and remained at elevated levels throughout the whole observation period. In contrast, FIV RNA levels within paired serum samples declined again after an initial peak between 14 dpi and 28 dpi. Concomitant with the onset of viral reproduction, microglia transiently upregulated expression of MHC class I and class II molecules. Virus-induced microglial activation was followed by a mild infiltration of peripheral leukocytes into the CNS parenchyma. The presented data suggest that microglia is infected by FIV very early after peripheral entry of the virus. Virus replicating microglia withstands eradication by brain-infiltrating leukocytes resulting in formation of a brain-resident virus reservoir, which probably cannot be cleared by peripheral chemotherapy.
Insights
Feline immunodeficiency virus (FIV) infects microglia early in cats, establishing a persistent brain reservoir. This viral reservoir in microglia resists eradication by infiltrating leukocytes, impacting feline central nervous system health.
Area of Science:
- Neuroscience
- Virology
- Immunology
Background:
- Microglia play a crucial role in central nervous system (CNS) immunity.
- Feline immunodeficiency virus (FIV) infection in cats serves as a model for lentiviral infections, including human immunodeficiency virus (HIV).
Purpose of the Study:
- To investigate the pathogenic role of microglia in the early stages of FIV infection in cats.
- To determine the kinetics of FIV replication within microglia and its impact on the CNS.
Main Methods:
- Real-time PCR was used to quantify FIV replication in microglia and serum.
- Expression of MHC class I and class II molecules on microglia was assessed.
- Leukocyte infiltration into the CNS was evaluated.
Main Results:
- Microglia showed detectable FIV replication by 14 days post-inoculation (dpi), persisting throughout the 6-month observation period.
- Serum FIV RNA levels peaked between 14-28 dpi and subsequently declined.
- Microglia upregulated MHC class I and II expression, followed by mild peripheral leukocyte infiltration into the CNS.
Conclusions:
- Microglia are infected very early by FIV after peripheral entry.
- Virus-replicating microglia form a persistent, brain-resident viral reservoir resistant to leukocyte-mediated clearance.
- This suggests challenges for treating FIV-associated neurological complications with peripheral chemotherapy.
