| Autor: |
Murphy, Brian R., Holley, H. Preston, Berquist, Erick J., Levine, Myron M., Spring, Susan B., Maassab, Hunien F., Kendal, Alan P., Chanock, Robert M. |
| Zdroj: |
Infection and Immunity; February 1979, Vol. 23 Issue: 2 p253-259, 7p |
| Abstrakt: |
Influenza A/Scotland/74 (H3N2) and A/Victoria/75 (H3N2) cold-adapted (ca) recombinant viruses, prepared by mating the A/Ann Arbor/6/60 (H2N2) cadonor virus and influenza A wild-type virus, were evaluated in adult seronegative volunteers (serum hemagglutination-inhibiting antibody titer, ≤1:8) for level of attenuation, antigenicity, and genetic stability of the temperature-sensitive and caphenotypes. At 107.0to 107.550% tissue culture infective doses the A/Scotland/74 and A/Victoria/75 carecombinant viruses were clearly attenuated and antigenic. However, one of eight vaccinees infected with 107.550% tissue culture infective doses of the A/Scotland/74 carecombinant had a febrile reaction (39°C). At a 10-fold higher dose (108.550% tissue culture infective doses), 4 of 12 A/Scotland/74 vaccinees had a febrile and/or systemic reaction. Febrile reactions were not observed in volunteers who received the A/Victoria/75 carecombinant virus, whereas 3 of the 12 vaccinees had mild upper respiratory tract symptoms, in one instance associated with mild systemic manifestations. Significantly, the serum hemagglutination- and neuraminidase-inhibiting antibody responses were comparable to those induced by wild-type virus. Both carecombinant viruses were shed in low titer for a short period of time. Each isolate retained the temperature-sensitive phenotype. However, there was evidence of genetic instability of the camarker in that 7 of 24 isolates exhibited some loss of the caproperty, and one isolate completely lost the capacity to produce plaques at 25°C. The retention of a low level of residual reactogenicity in the A/Scotland/74 carecombinant suggests that acquisition of the caand temperature-sensitive phenotypes by a carecombinant virus may not always bring about a satisfactory level of attenuation for individuals lacking hemagglutinin immunity. |
| Databáze: |
Supplemental Index |
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