Antibody response in humans after administration of whole-virion and split vaccine prepared from two different influenza A/swine viruses.

Previous findings with sera of several different animal species had indicated a close antigenic similarity between the X53 recombinant (possessing both surface antigens of A/Swine/New Jersey/76 virus) and the A/Swine/Ann Arbor/31 (AA) virus (1). Since the latter virus grows much better in chick embryos than the former, we examined the possibility of using the Ann Arbor virus instead of X53 for inactivated vaccine production. The present paper describes our findings in sera of subjects immunized with either whole-virus or split vaccine prepared from AA virus.