Fig 3.
Masking of epitope II by the N416-linked sugar. (A) SDS-PAGE analyses for the mobility of H proteins of different genotypes. MV-infected Vero/hSLAM cells at 36 h postinfection were labeled with [35S]methionine-cysteine and lysed in RIPA buffer. Polypeptides were then immunoprecipitated with a polyclonal Ab against MV and resolved by SDS-PAGE. (B) SDS-PAGE analyses for the mobility of H proteins of previously reported recombinant MVs possessing a chimeric H gene between the IC323 (genotype D3) and Edmonston (genotype A) strains or various point mutations. (C) Neutralizing assays of E128 against EGFP-expressing MV strains possessing a chimeric H gene between the IC323 (genotype D3) and Edmonston (genotype A) strains or various point mutations. The CIU of each virus was determined in II-18 cells in the presence or absence of E128. The CIU determined in the presence of E128 was compared with that in the absence of E128. The CIU in the absence of E128 was set to 100%. (D) SDS-PAGE analyses for the mobility of Endo-H-treated H proteins of different genotypes. (E) A five-residue alanine substitution in the H protein at residues 473 to 477 prevents binding of MAb E128. Immunoprecipitation of MV HFlag and CD46-binding defective MV HFlag-(473-477A) with MAbs CV1/CV4 and E128. The immunoprecipitated material was gel fractionated, followed by immunoblotting and detection of HFlag with an anti-Flag M2 antibody. IgG ctrl; control IgG.