Location of a neutralization determinant in the E protein of yellow fever virus (17D vaccine strain).

The location of a major antigenic determinant involved in the neutralization of a flavivirus, yellow fever virus (YF), has been defined in terms of its position in the amino acid sequence of the E protein. Neutralization escape variants of the 17D vaccine strain of YF were selected with two neutralizing monoclonal antibodies. Nucleotide sequencing of the envelope protein genes (E and M) of the variants showed that in each variant there was a single nucleotide change in the E gene leading to a nonconservative amino acid substitution in the E protein at position 71 or 72. The changes are in a region of the E protein which is hydrophilic, rich in cysteine residues, and not conserved between flavivirus subgroups. Since the selecting monoclonal antibodies neutralize attenuated 17D and virulent Asibi strains of YF with equal efficiency (J. J. Schlesinger, M. W. Brandriss, and T. P. Monath, 1983, Virology 125, 8-17), it can be concluded that the neutralization determinant defined for 17D YF is also present in Asibi YF.