Cross-protection of mice immunized with different influenza A (H2) strains and challenged with viruses of the same HA subtype.
Cross-protection of mice immunized with inactivated preparations of human and avian influenza A (H2) viruses was determined after lethal infection with mouse-adapted (MA) variants of human A/Jap x Bell/57 (H2N1) and avian A/NJers/78 (H2N3) viruses. The MA variants differed from the original strains by acquired virulence for mice and changes in the HA antigenicity. These studies indicated that mice vaccinated with human influenza A (H2) viruses were satisfactorily protected against challenge with A/Jap x Bell/57-MA variant; the survival rate was in the range of 61%-88.9%. Immunization of mice with the same viral preparations provided lower levels of protection against challenge with A/NJers/78-MA variant. Vaccination of mice with the avian influenza A (H2) viruses induced better protection than with human strains against challenge with both MA variants. Challenge with A/NJers/78-MA variant revealed that 76.2%-95.2% of animals were protected when vaccinated with avian influenza virus strains isolated before 1980, and that the protection reached only 52.4%-60.0% in animals vaccinated with strains isolated in 1980-1985. The present study revealed that cross-protection experiments in a mouse model could provide necessary information for the development of appropriate influenza A (H2) virus vaccines with a potential for these viruses to reappear in a human population.
Govorkova
E A
EA
D.I. Ivanovsky Institute of Virology, Russian Academy of Medical Sciences, Moscow, Russia.
Smirnov YuA
D000818:Animals; D003429:Cross Reactions; D004195:Disease Models, Animal; D009980:Influenza A virus / Q000145:classification / Q000276:immunology* / Q000472:pathogenicity; D007252:Influenza Vaccines / Q000276:immunology*; D051379:Mice; D009976:Orthomyxoviridae Infections / Q000401:mortality / Q000517:prevention & control*; D014611:Vaccination; D014613:Vaccines, Attenuated / Q000276:immunology
D007252:Influenza Vaccines; D014613:Vaccines, Attenuated