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Updated: Aug 23, 2026
Isolation of Murine Peritoneal Macrophages to Carry Out Gene Expression Analysis Upon Toll-like Receptors Stimulation
Published on: April 29, 2015
Susceptibility of peritoneal macrophages to infection by Theiler's virus
Mary Lou Jelachich1, Honey V Reddi, Mark D Trottier
1Department of Neurology & Microbiology-Immunology, Northwestern University, 2650 N. Ridge Ave., Evanston, IL 60201, USA.
Abstract:
Theiler's murine encephalomyelitis virus (TMEV) strains fall into two groups: high-neurovirulence GDVII virus results in rapidly fatal encephalitis, while low-neurovirulence BeAn and DA viruses produce persistent central nervous system (CNS) infection and inflammatory demyelinating disease. Because macrophages (Mphis) are key components in BeAn virus-induced demyelinating disease, we examined the susceptibility of primary peritoneal macrophages (pMphis) to BeAn infection in vitro. Freshly isolated, thioglycollate-elicited pMphis were resistant to BeAn virus infection even at high multiplicity of infection. In contrast, after incubation of thioglycollate-elicited pMphis at 37 degrees C for 4 days before infection, approximately half of the cells expressed virus antigen(s) and contained nicked DNA indicative of apoptosis. However, BeAn virus RNA replication and virus yields were highly restricted. Interestingly, about one-third of the cells were apoptotic but negative for virus RNA and antigen(s). Tumor necrosis factor-alpha (TNF-alpha) and interferon-alpha (IFN-alpha) were elevated in BeAn-infected pMphi cultures suggesting that bystander killing may be responsible for the apoptosis seen in BeAn virus antigen-negative cells. These data show for the first time that pMphis are susceptible to BeAn virus infection, although the infection is highly restricted and most of these cells undergo BeAn-induced apoptosis.
Insights
Primary macrophages resist BeAn virus infection but become susceptible after pre-incubation, leading to restricted viral replication and apoptosis. Elevated cytokines suggest bystander killing contributes to cell death in this Theiler's murine encephalomyelitis virus model.
Area of Science:
- Virology
- Immunology
- Neuroscience
Background:
- Theiler's murine encephalomyelitis virus (TMEV) causes central nervous system (CNS) disease.
- Low-neurovirulence TMEV strains induce persistent infection and inflammatory demyelinating disease.
- Macrophages are implicated in TMEV-induced demyelination.
Purpose of the Study:
- To investigate the susceptibility of primary peritoneal macrophages (pMphis) to BeAn virus infection in vitro.
- To characterize the cellular response and viral replication within macrophages upon BeAn infection.
Main Methods:
- Primary peritoneal macrophages were isolated and elicited using thioglycollate.
- Cells were incubated prior to infection with BeAn virus at high multiplicity.
- Virus antigen expression, DNA nicking (apoptosis), viral RNA replication, and cytokine levels (TNF-alpha, IFN-alpha) were assessed.
Main Results:
- Freshly isolated pMphis were resistant to BeAn infection.
- Pre-incubated pMphis showed susceptibility, with ~50% expressing viral antigens and exhibiting apoptosis.
- Viral RNA replication and yields were restricted, and ~33% of apoptotic cells were virus-negative.
- Elevated TNF-alpha and IFN-alpha suggest bystander killing contributes to apoptosis.
Conclusions:
- Primary peritoneal macrophages are susceptible to BeAn virus infection, but the infection is highly restricted.
- BeAn virus infection induces apoptosis in macrophages, potentially through direct viral effects and bystander killing.
- These findings provide insights into macrophage-TMEV interactions during CNS infection.
