Geoffrey C. Schild

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Seventeen of twenty-six influenza A virus isolates of the H1N1 antigenic subtype and two of eleven H3N2 virus isolates from the 1977-78 season exhibited a ts phenotype, were restricted in plaquing in MDCK cells at 38.5 degrees C compared to 34 degrees C and appeared to be naturally occurring ts mutants. The cut-off temperature for two such ts H1N1 virus(More)
Most of the small number of cases of poliomyelitis which occur in countries where Sabin's attenuated poliovirus vaccines are used are temporally associated with administration of vaccine and involve polioviruses of types 2 and 3 (ref. 1). Recent studies have provided convincing evidence that the Sabin type 2 and 3 viruses themselves may revert to a(More)
A monoclonal antibody raised against X-31 influenza virus reacted with the majority of natural H3N2 viruses isolated between 1968 and 1982. A number of variants of X-31 and of a receptor-binding mutant of X-31 were selected by the antibody during virus replication in eggs and MDCK cells. Antibody-binding assays indicated that the viruses selected were not(More)
BACKGROUND Influenza A viruses are of major concern for public health, causing worldwide epidemics associated with high morbidity and mortality. Vaccines are critical for protection against influenza, but given the recent emergence of new strains with pandemic potential, and some limitations of the current production systems, there is a need for new(More)
Extensive antigenic variability and a capricious epidemiology are characteristics of influenza A and B viruses of man. The haemagglutinin (HA) undergoes frequent and progressive antigenic drift as a result of selection, under immunological pressure, of viruses possessing alterations in the amino acid sequences at specific sites in the molecule. Here we(More)
The poliovirus type 3 Sabin oral poliovirus vaccine strain P3/Leon/12a1b differs in nucleotide sequence from its neurovirulent progenitor P3/Leon/37 by just 10 point mutations. The contribution of each mutation to the attenuation phenotype of the vaccine strain was determined by the construction of a series of recombinant viruses from infectious cDNA(More)
Antigenic changes are often induced in the haemagglutinin (HA) of human isolates of influenza A(H1N1) and B viruses during their isolation and propagation in embryonated hens' eggs. In this report we describe molecular changes in the HA of an A(H1N1) virus which accompany egg adaptation. The HA1 amino acid substitutions of egg-adapted variants are located(More)
An improved single-radial-diffusion technique for the assay of influenza haemagglutinin antigen is described. The modified method enables the results of assays of antigen to be obtained more rapidly and with greater precision than previously. The use of immunoplates containing varied, preselected concentrations of antihaemagglutinin antibody allows accurate(More)