Related Experiment Videos
Down regulation of murine MHC class I expression by bovine herpesvirus 1
M J Hariharan1, C Nataraj, S Srikumaran
1Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln 68583-0905.
Insights
Bovine herpesvirus 1 (BHV-1) infection reduces MHC class I expression in murine fibroblasts. Late viral gene products appear responsible for this immune evasion mechanism.
Area of Science:
- Immunology
- Virology
- Molecular Biology
Background:
- MHC class I molecules are crucial for immune surveillance.
- Viral infections often employ strategies to downregulate MHC class I expression to evade immune detection.
Purpose of the Study:
- To investigate the impact of bovine herpesvirus 1 (BHV-1) infection on MHC class I molecule expression in murine fibroblasts.
- To elucidate the role of viral gene products in BHV-1-mediated MHC class I downregulation.
Main Methods:
- Murine fibroblasts (L-cells) were infected with BHV-1 at a multiplicity of infection of 10 PFU/cell.
- MHC class I expression was quantified using flow cytometry and immunoprecipitation.
- The effects of phosphonoacetic acid (late protein synthesis inhibitor) and cycloheximide (total protein synthesis inhibitor) were assessed.
Main Results:
- BHV-1 infection led to a significant reduction in MHC class I expression starting at 8 hours post-infection, peaking between 10-16 hours.
- The downregulation of MHC class I was reversed by phosphonoacetic acid, indicating involvement of late viral gene products.
- Cycloheximide did not alter MHC class I expression levels in infected cells, further supporting the role of late viral proteins.
Conclusions:
- BHV-1 infection directly causes a decrease in MHC class I expression in murine fibroblasts.
- Late-acting viral gene products are implicated in the suppression of MHC class I expression.
- This mechanism may contribute to BHV-1-induced immune suppression in cattle.
Abstract:
The objective of this study was to investigate the effect(s) of bovine herpesvirus 1 (BHV-1) infection on the expression of MHC class I molecules in murine fibroblasts. L-cells were infected with BHV-1 at a multiplicity of infection (m.o.i.) of 10 plaque forming units (PFU) per cell, and the expression of MHC class I molecules was analyzed by flow cytometry and immunoprecipitation. Temporal studies revealed a reduction in class I expression beginning at 8 h post infection (p.i.) which reached a maximum between 10 to 16 h p.i. The loss of class I expression was restored in the presence of phosphonoacetic acid (30 micrograms/ml), a late herpesviral protein synthesis inhibitor. However, addition of cycloheximide, a total protein synthesis inhibitor (100 micrograms/ml), did not result in any difference in class I expression between virus-infected and mock-infected cells. These results suggest that the reduced class I expression is a direct consequence of BHV-1 infection, and that the late viral gene product(s) may be involved in this process. Similar phenomena may occur in natural BHV-1 infection in cattle, and this may be one of the mechanisms of immune suppression by BHV-1.