Antibody responses to pPB1-F2 PR8 vs. pPB1-F2 PR8 3KR after DNA immunization.

<p>The mice (n═ 5) were immunized four times at two-week intervals with 50 μg of pPB1-F2 PR8 or pPB1-F2 PR8 3KR DNA. MDCK cells were transfected with pPB1-F2 PR8 and lysed directly in the wells at 24 hr p. t. using SDS sample buffer. The proteins were separated through SDS-PAGE in a single well and transferred to nitrocellulose membrane. The sera were pooled after each dose and assayed for the presence of anti-PB1-F2 antibodies using immunoblotting on a sliced nitrocellulose membrane.