PECULIARITIES OF OBTAINING ATTENUATED THERMOSENSITIVE RECOMBINANTS OF INFLUENZA-A VIRUS AT THE END OF THE H3N2 EPIDEMIC CYCLE

Abstract

The conditions of obtaining thermosensitive (ts) recombinants [possible vaccine candidates] of the virulent A/Leningrad/82/76 (H3N2) virus with 2 donors of attenuation, A/Leningrad/134/17/57 (H2N2) and A/Leningrad/9/37/46 (H0N1), were evaluated. The recombinants were obtained by various methodical approaches (hybridization of native viruses, cross-reaction and selection of recombinants at 25, 32 and 40.degree. C) to study their effects on the degree of attenuation and the regularity of transmission of the ts marker. The recombinants examined varied in thermosensitivity which depended on the conditions of recombination of parent viruses. All recombinants studied, irrespective of their RCT40 marker, were innocuous for men.