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Complementation analysis of measles virus mutants isolated from persistently infected lymphoblastoid cell lines
Abstract:
Human lymphoblastoid cell lines persistently infected with measles virus release a heterogeneous population of virions. At least 80% of the infectious particles were temperature sensitive for plaque formation at 39 degrees C. Plaque-purified temperature-sensitive mutants from four persistently infected human lymphoblastoid cell lines were shown to be heterogeneous with respect to efficiency of plating at 31 and 39 degrees C, as well as to antigen and RNA production at 39 degrees C. The heterogeneity was confirmed by complementation analysis in which 21 temperature-sensitive isolates were found to represent at least four of the five previously described complementation groups of measles virus. Two isolates complemented four reference temperature-sensitive mutants. These isolates either represent new complementation groups or are members of the fifth complementation group, group E. The majority of isolates were found to have multiple mutations, and group B mutants (RNA-) predominated. Two temperature-sensitive isolates were able to interfere with production of parental measles virus at both permissive and nonpermissive temperatures.
Insights
Measles virus in human cells produces varied, temperature-sensitive particles. These measles virus mutants show genetic diversity and can interfere with normal virus production, impacting infection dynamics.
Area of Science:
- Virology
- Cell Biology
- Immunology
Background:
- Human lymphoblastoid cell lines can harbor persistent measles virus infections.
- Measles virus (MeV) virions released from infected cells are often heterogeneous.
Purpose of the Study:
- To characterize the temperature-sensitive (ts) measles virus mutants released from persistently infected human lymphoblastoid cell lines.
- To investigate the genetic diversity and functional properties of these MeV mutants.
Main Methods:
- Isolation and plaque purification of temperature-sensitive measles virus mutants.
- Efficiency of plating assays at permissive (31°C) and non-permissive (39°C) temperatures.
- Complementation analysis to determine genetic relatedness of mutants.
- Assessment of antigen and RNA production at elevated temperatures.
Main Results:
- Over 80% of infectious MeV particles were temperature-sensitive for plaque formation at 39°C.
- Isolated ts MeV mutants exhibited heterogeneity in plating efficiency, antigen, and RNA production.
- Complementation analysis revealed at least four previously described complementation groups, with potential new groups identified.
- A majority of mutants possessed multiple mutations, with RNA-deficient (Group B) mutants being predominant.
- Two ts isolates demonstrated interference with parental MeV production.
Conclusions:
- Persistently infected human lymphoblastoid cells release genetically diverse and functionally heterogeneous temperature-sensitive measles virus populations.
- The identified measles virus mutants, particularly RNA-deficient ones, may play a role in viral persistence and interference phenomena.
- Further characterization of these novel or Group E mutants could elucidate mechanisms of measles virus persistence and pathogenesis.