CHARACTERIZATION OF THE NUCLEOCAPSID PROTEIN OF HANTAAN VIRUS-STRAIN-76-118 USING MONOCLONAL-ANTIBODIES

We characterized the antigenic sites on the nucleocapsid protein (NP) of Hantaan virus (HTN) using 10 monoclonal antibodies (MAbs). At least seven antigenic sites were revealed by a competitive binding assay an d divided into three partially overlapping antigenic regions (I, II an d III). Regions I [amino acids (aa) 1-103], II (aa 104-204) and III (a a 205-402) were mapped on NP by examinincr the reactivity of truncated gene products. Those that corresponded to region I reacted with immun e mouse serum, indicating that the region contained major linear epito pes as reported with Four corners virus (FCV) and Puumala virus (PUU) NP. At least one MAb to each region inhibited viral growth when they w ere introduced into cells by scrape-loading. In addition, they conferr ed protection from a lethal HTN challenge to newborn mice. A PEPSCAN a ssay localized the epitope of MAb E5/G6 between aa 166-175. Since E5/G 6, which had the highest inhibitory effect both in cells and in mice, showed no virus neutralization activity by ordinary neutralization tes t, this region is suggested to be important for the virus growth after entry into the cells.