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Updated: Sep 11, 2026
Dissecting Innate Immune Signaling in Viral Evasion of Cytokine Production
Published on: March 2, 2014
Microinjection of interferon and 2',5'-oligoadenylate into mouse L cells and their effects on virus growth
Abstract:
By means of a new type of microinjection apparatus, which has a micropipette located in a hole through the optical axis of the condenser lens, we injected interferon (IFN) or 2',5'-oligoadenylate (2-5A) into mouse L cells, and observed their antiviral effects on the multiplication of vesicular stomatitis virus (VSV). After injection, cells were infected with VSV, and labeled with [3H]uridine in the presence of actinomycin D. The proportion of cells infected with VSV which carried radioactive virus-RNA was determined by autoradiography. IFN introduced directly into L cells had no effect on the virus growth. This result supports the idea that IFN molecules exert their effect from outside the cell membrane without penetrating into the cytoplasm. 2-5A, on the other hand, was able to inhibit the growth of VSV effectively when injected into L cells. The antiviral effect was dependent on the dose of 2-5A injected, and moreover the effect was transient, since it disappeared completely after 24-h incubation.
Insights
Interferon (IFN) did not inhibit virus growth when microinjected into cells, suggesting it acts externally. However, 2
Area of Science:
- Cell biology
- Virology
- Immunology
Background:
- Interferon (IFN) is a key antiviral protein.
- The mechanism of IFN action, particularly intracellularly, is not fully understood.
- 2',5'-oligoadenylate (2-5A) is a second messenger involved in IFN signaling.
Purpose of the Study:
- To investigate the intracellular antiviral effects of interferon (IFN) and 2',5'-oligoadenylate (2-5A) in mouse L cells.
- To determine if IFN acts from outside or inside the cell.
- To assess the dose-dependency and duration of the antiviral effect of 2-5A.
Main Methods:
- Development of a novel microinjection apparatus for intracellular delivery.
- Microinjection of IFN or 2-5A into mouse L cells.
- Infection of cells with vesicular stomatitis virus (VSV) and labeling with [3H]uridine in the presence of actinomycin D.
- Quantification of viral RNA synthesis using autoradiography.
Main Results:
- Intracellular IFN injection showed no significant inhibition of VSV replication.
- This suggests that IFN exerts its antiviral effect extracellularly.
- Microinjected 2-5A effectively inhibited VSV growth in a dose-dependent manner.
- The antiviral effect of 2-5A was transient, diminishing after 24 hours.
Conclusions:
- IFN likely acts on the cell surface to induce antiviral states.
- 2-5A can directly inhibit viral replication intracellularly.
- The intracellular antiviral pathway involving 2-5A is effective but temporary.
