A method of alphavirus replicon particle titration based on expression of functional replicase/transcriptase

Seema S. Gangolli, Nikolaos Vasilakis, Gerald R. Kovacs, Timothy J. Zamb, Jacek Kowalski

Research output: Contribution to journalArticle

2 Scopus citations


Alphavirus replicon particles are being exploited for a variety of purposes both in vitro as gene expression vectors, and in vivo as vaccines or gene therapy vectors. There is a need for a simple and universal method of titration of replicon particles that is independent of expression of the foreign protein. We devised a method that uses modified vaccinia virus Ankara (MVA) as an indicator virus, to deliver a Venezuelan equine encephalitis virus (VEE) defective helper RNA encoding green fluorescent protein (GFP). Co-infection of cells with the MVA-based indicator and Venezuelan equine encephalitis virus replicon particles (VRP) results in expression of the GFP gene. VRP titer is readily determined by counting fluorescent cells.

Original languageEnglish (US)
Pages (from-to)133-138
Number of pages6
JournalJournal of Virological Methods
Issue number2
StatePublished - May 2003
Externally publishedYes



  • Alphaviruses
  • Replicon particles
  • Titration
  • Venezuelan equine encephalitis virus

ASJC Scopus subject areas

  • Virology

Cite this