Single-particle fusion of influenza viruses reveals complex interactions with target membranes

Guus van der Borg, Scarlett Braddock, Jelle Blijleven, Antoine van Oijen, Wouter Roos

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The first step in infection of influenza A virus is contact with the host cell membrane, with which it later fuses. The composition of the target bilayer exerts a complex influence on both fusion efficiency and time. Here, an in vitro, single-particle approach is used to study this effect. Using total internal reflection fluorescence (TIRF) microscopy and a microfluidic flow cell, the hemifusion of single virions is visualized. Hemifusion efficiency and kinetics are studied while altering target bilayer cholesterol content and sialic-acid donor. Cholesterol ratios tested were 0%, 10%, 20%, and 40%. Sialic-acid donors GD1a and GYPA were used. Both cholesterol ratio and sialic-acid donors proved to have a significant effect on hemifusion efficiency. Furthermore, comparison between GD1a and GYPA conditions shows that the cholesterol dependence of the hemifusion time is severely affected by the sialic-acid donor. Only GD1a shows a clear increasing trend in hemifusion efficiency and time with increasing cholesterol concentration of the target bilayer with maximum rates for GD1A and 40% cholesterol. Overall our results show that sialic acid donor and target bilayer composition should be carefully chosen, depending on the desired hemifusion time and efficiency in the experiment.

Original languageEnglish
Article number204005
Number of pages7
JournalJournal of Physics-Condensed Matter
Issue number20
Early online date6-Apr-2018
Publication statusPublished - 23-May-2018


  • influenza
  • membrane
  • membrane fusion
  • hemifusion
  • sialic-acid
  • fusion
  • cholesterol

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