Biomedical subjects
Publications and source records attributed to G Florent.
The genotypic composition of several H3N2 vaccinal strains made from PR/8/34 and different wild isolates has been determined. The results suggested that specific gene constellations at the level of the 3 largest RNA fragments, coding the 3 "polymerase proteins" are responsible for their consistent attenuation.
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The RIT 4199 (H3N2) strain was obtained by recombination of PR/8/34 (H0N1) and A/Alaska/5/77 (H3N2) isolates. Its genetic composition was determined by RNA-RNA hybridization and by identification by gel electrophoresis of the double-standard RNA formed. The RIT 4199 was inoculated intranasally to 27 seronegative volunteers at a dose of 10(7.3)EID50. The results show that it is suitable for live vaccine strain.
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Extensive use of recombinants made from A/PR/8/34 (H0N1) and wild, virulent H3N2 viruses as live influenza vaccines has provided a number of viruses of defined virulence for man. Clinical symptoms produced by these strains have ranged from febrile influenza to local coryzal symptoms or nil. A study was therefore made of the extent to which the PR8 genome had been incorporated into that of a number of the recombinants. By RNA--RNA hybridization it seemed that recombinants which had 55 per cent of greater homology with the PR8 parent were likely to conform an acceptable standard of attenuation. Those with lesser homology were frequently, but not always, clinically virulent. The technique seemed potentially useful, therefore, for screening PR8 live vaccine recombinants in vitro before giving them to volunteers.
Rabbit antiallotype sera raised against heavy chain markers sometimes show double precipitin lines with all or some of the corresponding antigens (double and single line phenotypes). In a number of cases the double line phenotypes behave as alleles of the single line phenotypes and this feature allows a genetic and immunochemical analysis of these systems. In three cases that have been analysed, the double line phenotype arise when a precipitating a locus allotype and a non-precipitating d or e locus allotype are present on the same molecule (a1 and d14), (a1 and d11), (a3 and d11). This only happens when the corresponding genes are present on the same chromosome (cis configuration) of the diploid pair. These sera are therefore useful for determining directly the genotype of the animals.
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The amino acid sequence of the micro, chain of a human IgM immunoglobulin, including the location of all disulfide bridges and oligosaccharides, has been determined. The homology of the constant regions of immunoglobulin micro, gamma, alpha, and epsilon heavy chains reveals evolutionary relationships and suggests that two genes code for each heavy chain.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
A study is described of the RNAs of recombinant viruses made from A/PR/8/34, which is non-infectious for man, and wild human Influenza A strains. By RNA-RNA hybridization it was possible to determine the proportion of the genome donated by each of the parents. The technique can be applied as a biochemical marker to detect the recombinants among parental viruses and moreover, it is a method to select the attenuated viruses among the recombinants.