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Table 3 Protection of mice against lethal heterologous influenza A virus challenge by DNA prime-intranasal protein boost strategy based on NP vaccine

From: Induction of cross-protection against influenza A virus by DNA prime-intranasal protein boost strategy based on nucleoprotein

Group

Immunization

Lung virus titer (log10TCID50/ml)a

Survival rate (No. Of survivors/no. tested)

DNA prime

rNP boost

3 days

5 days

7 days

D1P1

once

once

6.41±0.13b

4.61±0.35b

0.67±0.58b

10/10b

D2P1

twice

once

6.22±0.16b

4.00±0.33b

0.41±0.71b

10/10b

Control

-

-

7.17±0.24

6.72±0.25

6.17±0.58

0/10

  1. Mice of three groups were immunized as described above. 3 weeks after the last immunization, mice were challenged with a lethal dose (5×LD50) of influenza virus A/Chicken/JiangSu/07/2002 (H9N2). Bronchoalveolar washes from three mice in each group were collected 3 days, 5 days and 7 days post-infection for titration of lung virus respectively.
  2. The survival rate of mice 21 days post-infection was determined.
  3. a Results are expressed as mean ± SD of tested mice in each group.
  4. b Displays significant difference compared with mouse in control groups (P<0.05).