FIG. 4.
Serum IgG response to Nuc. Ten chickens were immunized with 109 bacteria (black dots, negative control [strain VE5505 containing pVE5502]; white dots, strain VE5671 containing pVE5540 and producing anchored Nuc-VP2) for 5 consecutive days starting at days 0 and 14 (indicated by filled triangles). Individual serum samples were collected at days 0 (before the first administration), 14, and 21 and tested by enzyme-linked immunosorbent assay for NucA-specific IgG. *, P < 0.02; **, P < 0.016 (Student's t test). A.U.450nm, units of absorption at 450 nm.