Amino Acid Substitutions in Matrix, Fusion and Hemagglutinin Proteins of Wild Measles Virus for Adaptation to Vero Cells

Background: Wild-type measles virus (MV) is isolated in B95a but not in Vero cells. Through an adaptation process of wild-type MV to Vero cells, several amino acid substitutions were reported. Methods: Six strains were adapted to Vero cells and membrane (M), fusion (F) and hemagglutinin (H) genes were sequenced. Cell fusion was assessed and recombinant MVs were constructed, having wild-type H or M gene with or without mutations. Results: No F gene substitution was noted. Amino-acid substitutions at positions 481 from Asn to Tyr (N481Y) and 546 from Ser to Gly (S546G) were observed in the H protein. Glu at position 89 of the M protein was substituted for Gly (E89G) and two mutations were noted at positions 62 (S62R) and 83 (S83P) in M protein. Recombinant viruses with mutation(s) detected in Vero-adapted strains induced a cytopathic effect and grew well in Vero cells, but those with the wild type did not. Recombinant viruses with mutation(s) demonstrated lower viral growth in B95a cells. Conclusions: Substitutions of E89G, S62R and S83P of the M protein were newly observed through adaptation to Vero cells, besides the mutations described in previous reports, with varying adaptation for each strain. Copyright © 2011 S. Karger AG, Basel Received: January 27, 2010 Accepted after revision: July 26, 2010 Published online: January 13, 2011 Tetsuo Nakayama, MD Laboratory of Viral Infection I Kitasato Institute for Life Sciences, Kitasato University Shirokane 5-9-1, Minato-ku, Tokyo 108-8641 (Japan) Tel. +81 3 5791 6269, Fax +81 3 5791 6130, E-Mail tetsuo-n @ lisci.kitasato-u.ac.jp © 2011 S. Karger AG, Basel 0300–5526/11/0544–0217$38.00/0 Accessible online at: www.karger.com/int D ow nl oa de d by : 54 .1 91 .4 0. 80 9 /1 6/ 20 17 8 :2 4: 16 P M