Methods: Hep-2 cells were preincubated with DAS181 or control DAS185 (a mutated sialidase) prior to inoculation with human metapneumovirus strains. Infectivity was assessed by a cell-based ELISA quantitating human metapneumovirus matrix protein. The effect of DAS181 on binding of recombinant G attachment protein was also determined.
Results: DAS181 blocked infection of human metapneumovirus strains A2, B1, and B2 at low concentrations. No effect of DAS185 was observed. Binding of MPV G protein to Hep-2 cells was also markedly inhibited by preincubation of cells with DAS181.
Conclusions: These results suggest that human metapneumovirus may utilize sialic acids as an entry cofactor. DAS181 may thus represent a new therapeutic agent useful for the treatment of human metapneumovirus.
Keywords: DAS181; Human metapneumovirus; attachment; infectivity; sialic acids; sialidase fusion protein.