title: Passage in Vero cells alters the characteristics of measles AIK-C vaccine strain.
abstract: Objective of this study is to evaluate the feasibility of measles vaccine production in Vero cell culture. We constructed the full-length cDNA, pIC-MVAIK-F278Leu (small plaque-type) and pIC-MVAIK-F278Phe (large plaque-type) from the AIK-C measles vaccine strain attenuated from the Edmonston wild-type. MVAIK-S/B2 was rescued from pIC-MVAIK-F278Leu after two passages in B95a cells and MVAIK-SL/B2V1 was obtained through large plaque cloning in Vero cells. MVAIK-SL/B2V8 was obtained after eight passages in Vero cells. It produced large plaques in Vero cells, grew well at 39 degrees C, and thus the characteristics of the AIK-C vaccine strain were lost. Thirteen amino acid changes were observed; one in the N, two in the P, one in the C, three in the F, one in the H, and five in the L protein regions. Twelve of these changes excluding one in the L gene were back mutated to the Edmonston strain. Change from Leu to Phe at position 278 of the F protein was an early event during adaptation to Vero cells and the P gene was back-mutated to the Edmonston wild-type. As for the control, MVAIK-L/B9 strain was obtained after passages in B95a cells from pIC-MVAIK-F278Phe (large plaque-type). It maintained the same temperature sensitivity as the AIK-C vaccine strain and only four amino acid changes, one in the N and three in the L protein region, were observed without any mutations in the P, C, M, F, and H genes. The passage of the measles vaccine AIK-C strain in Vero cells lost the characteristics of small plaque inducibility and temperature sensitivity (ts) phenotype.
authors.affiliation: Laboratory of Viral Infection I, Kitasato Institute for Life Sciences, Kitasato University, Minato-ku, Tokyo, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Uejima
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Nakayama
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Komase
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002522:Chlorocebus aethiops; D042822:Genomic Instability; D008458:Measles Vaccine / Q000235:genetics*; D009154:Mutation; D013696:Temperature; D014613:Vaccines, Attenuated / Q000235:genetics; D014614:Vaccines, Synthetic / Q000235:genetics*; D014709:Vero Cells
chemical_list: D008458:Measles Vaccine; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic