Kinetic analysis of the influenza A virus HA/NA balance reveals contribution of NA to virus-receptor binding and NA-dependent rolling on receptor-containing surfaces
(A) Schematic representation of the experimental set-up. Colours of the sensors correspond with the colours of the lines in (B) and (C). 6’N transferrin bt is indicated by the large Xs. Origin of the HA and NA proteins of the viruses used is indicated as well as the absence of presence of OC during the incubation of the sensors with the viruses. The left and right panels correspond with the graphs shown in (B) and (C), respectively. (B) Biotinylated 6’N transferrin bt was loaded to maximum levels on Streptavidin sensors and bound with 100 pM PR8MtSIN or TX77NAMtSIN in absence or presence of 10 μM OC as indicated. (C) Sensors bound in (B) with virus were regenerated at pH2, removing all virus particles, and subsequently bound again with 100 pM TX77NAMtSIN to assess the extent of desialytion that occurred in (B) by neuraminidase activity.