Intragenic suppression of a deletion mutation of the nonstructural gene of an influenza A virus.

The influenza A/Alaska/77 (H3N2) virus mutant 143-1 is temperature sensitive (ts) due to a spontaneous in-frame 36-nucleotide deletion in the nonstructural (NS) gene segment, which leads to a 12-amino-acid deletion in the NS1 protein. In addition, it has a small-plaque phenotype on MDCK cell monolayers. However, phenotypically revertant (i.

Antigenic relatedness among the Norwalk-like agents by serum antibody rises.

The Norwalk, Snow Mountain (SMA), and Hawaii agents are etiologically associated with separate outbreaks of acute viral gastroenteritis. Previous cross-challenge of volunteers, immune electron microscopy, and/or enzyme-immunoassay analysis suggested that these agents are antigenically distinct. We examined paired sera from human volunteers challenged with these agents for the presence of homologous and heterologous serum antibody titer rises to the agents.