Related Experiment Videos
Abortive replication of influenza virus A/WSN/33 in HeLa229 cells: defective viral entry and budding processes
C N Gujuluva1, A Kundu, K G Murti
1Department of Microbiology and Immunology, Jonsson Comprehensive Cancer Center, University of California at Los Angeles, School of Medicine 90024-1747.
Abstract:
Since influenza A virus replication is defective in HeLa229 cells but productive in Madin-Darby canine kidney (MDCK) cells, we have investigated the steps in the infectious cycle of A/WSN/33 virus defective in HeLa229 cells. We find that both the entry and exit processes of the infectious cycle were defective in HeLa229 cells. During entry, viral adsorption was apparently normal in HeLa229 cells but a subsequent step(s) involving one or more processes namely the fusion/uncoating and nuclear transport of viral ribonucleoprotein was inefficient and slow compared to those in MDCK cells. Fewer HeLa229 cells were infected at the same multiplicities of infection, resistance to ammonium chloride developed much more slowly and degradation of the incoming virus proteins was delayed when compared to those in MDCK cells. Subsequent to the entry process, there was no significant difference in either the synthesis of viral proteins or the transport, maturation, and membrane insertion of viral glycoproteins although the glycosylation pattern of hemagglutinin was different and the peak protein synthesis was albeit delayed in HeLa229 cells compared to that in MDCK cells. However, there was a major defect in the budding and release of viral particles. In HeLa229 cells, viral bud formation occurred but viral particles remained attached to the plasma membrane and were not released into the medium. This defect in virus release was not due to lack of neuraminidase activity but could be, at least partly, overcome by cytochalasin B treatment, suggesting a possible involvement of microfilaments in virus release. These results indicate that the abortive replication of influenza virus A/WSN/33 in HeLa229 cells appears to be due to multiple defects involving both the entry and release of viral particles and that host cell membrane and microfilaments may be important contributing factors in these processes.
Insights
Influenza A virus replication is defective in HeLa229 cells due to inefficient viral entry and impaired particle release. Host cell factors, including microfilaments, are implicated in these influenza virus replication defects.
Area of Science:
- Virology
- Cell Biology
Background:
- Influenza A virus replication is cell-type dependent, being productive in Madin-Darby canine kidney (MDCK) cells but defective in HeLa229 cells.
- Investigating these differences reveals key host-pathogen interactions.
Purpose of the Study:
- To elucidate the specific steps in the influenza A virus (A/WSN/33) infectious cycle that are defective in HeLa229 cells compared to MDCK cells.
Main Methods:
- Comparative analysis of viral entry, replication, and release in HeLa229 and MDCK cells.
- Assessment of viral protein synthesis, glycoprotein transport, and particle budding.
- Investigation of the role of host cell factors like microfilaments and neuraminidase activity.
Main Results:
- Viral entry into HeLa229 cells showed defects in fusion/uncoating and nuclear transport, leading to slower infection development.
- While viral protein synthesis was largely unaffected, hemagglutinin glycosylation differed, and protein synthesis peaked later in HeLa229 cells.
- A significant defect in viral particle budding and release was observed in HeLa229 cells, with particles remaining attached to the plasma membrane.
- This release defect was not due to neuraminidase activity but could be partially rescued by cytochalasin B, suggesting microfilament involvement.
Conclusions:
- Abortive influenza A virus replication in HeLa229 cells results from multiple defects in both viral entry and particle release.
- Host cell membrane properties and the microfilament cytoskeleton play crucial roles in these defective processes.