Comparative studies of wild-type and cold-mutant (temperature-sensitive) influenza viruses: nonrandom reassortment of genes during preparation of live virus vaccine candidates by recombination at 25 degrees between recent H3N2 and H1N1 epidemic strains and cold-adapted A/An Arbor/6/60. |
| |
Authors: | N J Cox H F Maassab A P Kendal |
| |
Affiliation: | 1. World Health Organization Collaborating Center for Influenza, Bureau of Laboratories, Center for Disease Control, Public Health Service, U. S. Department of Health, Education, and Welfare, Atlanta, Georgia 30333 USA;2. Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan 48104 USA |
| |
Abstract: | Genetic compositions of 35 recombinant cold-adapted influenza A(H3N2 and H1N1) candidate live attenuated vaccine strains have been determined. The viruses, which had been obtained by recombination (reassortment) at 25° between contemporary epidemic wild-type strains and cold-adapted A/Ann Arbor/6/60(H2N2), followed by selection for growth at 25° of virus with wild-type HA and NA, have a highly restricted genetic composition. Eighteen of the thirty-five recombinants had RNAs coding for the three polymerase (P) proteins, NP, M, and NS, from the cold-adapted mutant A/Ann Arbor/6/60 had only the HA and NA of the wild-type strains. Only 4 out of 64 theoretically possible combinations of genes coding for nonglycoprotein viral products were detected. The restricted genetic composition of cold-adapted recombinants produced at 25° supports the evaluation of this method of preparing live vaccine strains to determine whether recombinants with constant gene composition have predictable levels of attenuation for man. |
| |
Keywords: | To whom reprint requests should be addressed. |
本文献已被 ScienceDirect 等数据库收录! |
|