Humoral immune responses.

<p>Sera from CEF control group (n = 10), parental HVT group (n = 10) and rHVT-<i>pmpD</i>-N group (n = 15) were analyzed by ELISA assay for anti-PmpD-N antibody using plates coated with PmpD-N as the antigens as described in material and method section. Results are expressed as absorbance at 450nm/630nm. A serum sample was considered positive when its OD value exceeded 0.045. The values were shown as means ± standard deviation. ** Indicates <i>P</i> < 0.01 when rHVT-<i>pmpD</i>-N & parental HVT group or CEF control group.