THE GLYCOPROTEIN OF VIRAL HEMORRHAGIC SEPTICEMIA VIRUS (VHSV) - ANTIGENICITY AND ROLE IN VIRULENCE

In order to study the antigenic structure of the G protein of VHSV, we produced several anti-G monoclonal antibodies (MAbs) and used 4 neutr alizing MAbs (NMAbs) to select resistant (MAR) mutants. Each MAR mutan t was confronted with the 4 NMAbs in a neutralization test, and also w ith our panel of MAbs in surface plasmon resonance (SPR) analysis to d etermine the extent of their relatedness. Determination of the sequenc e of the entire G gene of representative MAR mutants allowed us to map the mutations responsible for the resistant phenotypes. We identified several locations on the G protein sequence, which represent, most pr obably, critical positions within the binding sites of the neutralizin g MAbs. In addition, the MAR mutants selected with a cross-reactive MA b exhibited a reduced pathogenicity for fish. This indicated that the regions bearing the point mutations selected with MAb C10 were probabl y involved in the determination of the virulent phenotype.