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R Crainic

Publications and source records attributed to R Crainic.

82 records · Page 5Linked to original sources
PubMedDate not supplied

Construction of a chimaeric type 1/type 2 poliovirus by genetic recombination.

A chimaeric poliovirus carrying a type-2-specific neutralization epitope on a type 1 capsid was created by site-directed mutagenesis of the Mahoney strain of poliovirus type 1. An EcoRV and a HindIII restriction sites were first constructed in the cDNA of poliovirus type 1 at nucleotide positions 2756 and 2786, respectively, i.e. on either side of the sequence encoding neutralization epitope C3 (VP1 amino acids 93-103), which is part of neutralization site NImI. The cDNA sequence framed by the two sites was next taken out and replaced by custom-made oligonucleotides encoding the equivalent region of VP1 from the Lansing strain of poliovirus type 2. The DNA from the plasmid carrying such a hybrid construct was transfected onto CV1 cells generating a chimaeric virus, v510. Neutralization of v510 with a panel of monoclonal antibodies showed that v510 has lost the poliovirus type 1 C3 epitope but acquired a new, poliovirus type-2-specific neutralization epitope. Preliminary results indicate that v510 also shows neurovirulence for mice, which is a specific trait of the Lansing strain of poliovirus type 2.

Antibodies, Monoclonal↗
PubMedDate not supplied

Antigenic variation of poliovirus studied by means of monoclonal antibodies.

The natural distribution of poliovirus neutralization epitopes was studied on several field isolates of each of the three serotypes by a neutralization index test for which a panel of homotypic monoclonal antibodies was used. Two categories of neutralization epitopes were detected: strain-specific or variable epitopes, and cross-reacting or common epitopes. The latter tended to be conserved among homotypic viruses. Some of the Sabin-specific neutralization epitopes were found to be mutually exclusive of wild-type epitopes, but coexistence of Sabin-specific and wild-type epitopes was found in other cases. During virus excretion by infants fed type 1 Sabin vaccine, the Sabin-specific neutralization epitope was lost, and sometimes the original epitope motif of the parental wild (Mahoney) virus was recovered. Epitope variation was also expressed by loss of epitope function in virus neutralization without modification of antigenic conformation.

Antibodies, Monoclonal↗
PubMedDate not supplied

[Supplementary data on the theory concerning the cyclic evolution of influenza viruses].

The distribution per age groups of antibodies to influenza viruses A/Hong Kong/1/68, A/England/837/69 and A/England/42/72 in the sera collected in 1970 demonstrates that antigenically similar strains also dominated the epidemiologic picture of influenza in the past century. The results suggest that the pandemic of 1893 and infection in persons born before 1885 were caused by a strain similar to A/Hong Kong/1/68 and in those born in 1895-1897 by the antigenic variant A/England/42/72. The anamnestic response to the A/England/69 variant, following upon vaccination with the Hong Kong strain shows that the primary infection in persons born before 1900 was caused by a strain antigenically similar to the first variant. The data obtained lend support to the hypothesis of antigenic recycling of influenza virus and of the finite character of the antigenic variation of influenza viruses.

Age Factors↗