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Characterization of measles viruses in establishment of persistent infections in human lymphoid cell line
Abstract:
Human lymphoid cells (NC-37) were infected with attenuated measles vaccine virus (Schwarz, AIK-C, and CAM-70 strains), subacute sclerosing panencephalitis virus (Mantooth and Halle strains), neurovirulent TYCSA strain, and wild type virus (Edmonston and Toyoshima strains) at an input multiplicity of 0-01. These strains were divided into two groups by their capacity to establish carrier states. CAM-70, Toyoshima, and Edmonston strains did not set up persistent infections in NC-37 cells, whereas AIK-C strain induced chronic cyclic infection and the Schwarz, TYCSA, Mantooth and Halle strains could set up persistent infections and furthermore two types of persistent infections were recognizable. Cells persistently infected with Schwarz strain contained nucleocapsid structures in both nucleus and cytoplasm, and produced infectious virus of 10(4) to 10(5) p.f.u./ml over 100 days after the inoculation of the virus but the cap-formation of measles antigens on the cell membrane was seldom observed. However, in cells persistently infected with TYCSA strain, nucleocapsid structures were rarely observed in the nucleus, but the cap-formation of measles antigens on the cell membrane was often observed. The titre of carried virus was always higher than the number of cells in the range of 10(6) to 10(7) p.f.u./ml. Mantooth strain was similar to Schwarz strain and Halle strain was similar to TYCSA strain in the properties of their carrier states. These carrier states were stable and the cells grew normally for over one year.
Insights
Measles virus strains establish persistent infections in human lymphoid cells, with two distinct carrier states identified based on viral antigen expression and replication patterns. These stable infections persisted for over a year.
Area of Science:
- Virology
- Cell Biology
- Immunology
Background:
- Measles virus (MeV) can cause persistent infections, including subacute sclerosing panencephalitis (SSPE).
- Understanding the mechanisms of MeV persistence is crucial for developing effective interventions.
Purpose of the Study:
- To investigate the capacity of different measles virus strains to establish persistent infections in human lymphoid cells (NC-37).
- To characterize the distinct types of persistent infections based on viral antigen expression and replication.
Main Methods:
- Infection of NC-37 cells with various attenuated, neurovirulent, and wild-type measles virus strains.
- Monitoring of viral replication, antigen expression (nucleocapsid and cell surface), and cell viability over extended periods.
Main Results:
- Measles virus strains were categorized into two groups based on their ability to establish persistent infections.
- One group (CAM-70, Toyoshima, Edmonston) did not establish persistent infections.
- The other group (AIK-C, Schwarz, TYCSA, Mantooth, Halle) established persistent infections, with two distinct carrier states observed.
- Schwarz and Mantooth strains showed nucleocapsid structures in nucleus/cytoplasm, high infectious virus production, and rare cell membrane antigen capping.
- TYCSA and Halle strains showed rare nuclear nucleocapsid structures, frequent cell membrane antigen capping, and very high infectious virus titers.
Conclusions:
- Different measles virus strains exhibit distinct tropisms and replication strategies within human lymphoid cells.
- Two distinct patterns of persistent measles virus infection were identified, characterized by differences in viral antigen localization and cell surface expression.
- These findings contribute to understanding measles virus pathogenesis and the development of persistent infections.