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Updated: Aug 14, 2026
Isolation of Brain-infiltrating Leukocytes
Published on: June 13, 2011
Monocytes/macrophages isolated from the mouse central nervous system contain infectious Theiler's murine
R J Clatch1, S D Miller, R Metzner
1Neuroscience Program, Northwestern University Medical School, Chicago, Illinois 60611.
Abstract:
Knowledge of the cells in which Theiler's murine encephalomyelitis virus (TMEV) persists is crucial to understanding the pathogenesis of TMEV-induced demyelinating disease; however, it is still uncertain whether oligodendrocytes or macrophages are the primary target for persistence. In this study, mononuclear cells (MNC) isolated directly from central nervous system (CNS) inflammatory infiltrates of TMEV-infected mice on discontinuous Percoll gradients were found to contain infectious TMEV. Macrophages appeared to be the principal MNC infected as determined by two-color immunofluorescence. Infectious center assay and double immunostaining together indicated the presence and possible synthesis of TMEV in approximately 1 in 225 to 1 in 1000 CNS macrophages, with 1 to 7 PFU produced per macrophage. On the basis of these findings, limited replication in macrophages is consistent with the total CNS virus content detected at any time during the persistent phase of the infection as well as the slow pace of the infection.
Insights
Theiler
Area of Science:
- Neuroimmunology
- Virology
- Pathogenesis
Background:
- Theiler's murine encephalomyelitis virus (TMEV) causes demyelinating disease.
- Identifying persistent virus reservoirs is key to understanding pathogenesis.
- Oligodendrocytes and macrophages are potential TMEV persistence targets.
Purpose of the Study:
- To determine the primary cell type for TMEV persistence in the central nervous system (CNS).
- To investigate the role of macrophages in TMEV pathogenesis.
Main Methods:
- Isolation of mononuclear cells (MNC) from CNS inflammatory infiltrates of TMEV-infected mice.
- Two-color immunofluorescence to identify infected MNC.
- Infectious center assay and double immunostaining to quantify viral presence and replication.
Main Results:
- Infectious TMEV was detected in MNC from the CNS.
- Macrophages were identified as the principal infected MNC.
- TMEV was present and possibly synthesized in CNS macrophages at low levels (1-7 PFU/macrophage).
Conclusions:
- Macrophages are the primary cell type for TMEV persistence in the CNS.
- Limited viral replication in macrophages explains the low overall CNS virus content during persistent infection.
- Findings advance understanding of TMEV-induced demyelinating disease pathogenesis.
