TY - JOUR
T1 - Target cell membrane sialic acid modulates both binding and fusion activity of influenza virus
AU - Pedroso de Lima, Maria C.
AU - Ramalho-Santos, João
AU - Flasher, Diana
AU - Slepushkin, Vladimir A.
AU - Nir, Shlomo
AU - Düzguneş, Nejat
PY - 1995/6/14
Y1 - 1995/6/14
N2 - Influenza virus binds to cell surface sialic acid receptors, and following endocytosis fuses with the endosome membrane at low pH. Whether sialic acid plays a role in the virus-cell membrane fusion step is not known. We investigated the effect of the removal of cell membrane sialic acid on the fusion activity of influenza virus (A/PR/8/34 strain) toward human T lymphocytic leukemia (CEM) cells at low pH. Fusion was monitored by fluorescence dequenching of octadecylrhodamine incorporated in the virus membrane. Removal of sialic acid by neuraminidase resulted in a drastic reduction in both viral binding and fusion. The association of the virus with neuraminidase-treated cells was enhanced at pH 5, compared to that at neutral pH, probably due to the unfolding of the hemagglutinin and the resulting increase in viral surface hydrophobicity, but the fusion capacity of the virus was reduced significantly. The results were analysed with a mass-action kinetic model which could explain and predict the kinetics of fusion. Our results indicate that binding of influenza virus to sialic acid residues on the cell surface leads to rapid and extensive fusion and partially inhibits the low pH-induced viral inactivation.
AB - Influenza virus binds to cell surface sialic acid receptors, and following endocytosis fuses with the endosome membrane at low pH. Whether sialic acid plays a role in the virus-cell membrane fusion step is not known. We investigated the effect of the removal of cell membrane sialic acid on the fusion activity of influenza virus (A/PR/8/34 strain) toward human T lymphocytic leukemia (CEM) cells at low pH. Fusion was monitored by fluorescence dequenching of octadecylrhodamine incorporated in the virus membrane. Removal of sialic acid by neuraminidase resulted in a drastic reduction in both viral binding and fusion. The association of the virus with neuraminidase-treated cells was enhanced at pH 5, compared to that at neutral pH, probably due to the unfolding of the hemagglutinin and the resulting increase in viral surface hydrophobicity, but the fusion capacity of the virus was reduced significantly. The results were analysed with a mass-action kinetic model which could explain and predict the kinetics of fusion. Our results indicate that binding of influenza virus to sialic acid residues on the cell surface leads to rapid and extensive fusion and partially inhibits the low pH-induced viral inactivation.
KW - CEM cell
KW - Fluorescence
KW - Influenza virus
KW - Membrane binding
KW - Membrane fusion
KW - Neuraminidase
KW - Sialic acid
UR - http://www.scopus.com/inward/record.url?scp=0029026187&partnerID=8YFLogxK
U2 - 10.1016/0005-2736(95)00067-D
DO - 10.1016/0005-2736(95)00067-D
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
C2 - 7794972
AN - SCOPUS:0029026187
SN - 0005-2736
VL - 1236
SP - 323
EP - 330
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
IS - 2
ER -