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Table 2 Enhancement by chIL-7 of IBDV vaccine-induced protection following challenge with virulent IBDV

From: Recombinant chicken interleukin-7 as a potent adjuvant increases the immunogenicity and protection of inactivated infectious bursal disease vaccine

Groups

Mortalitya

Survival rate (%)b

B/B ratiosc

Histopathological BF lesion scoresd

Protectione (%)

IBDV in BTf (TCID50)/g

IBDV in NSg (TCID50)/mL

0

1

2

3

4

5

Control unchallenged

0/32

100

7.31 ± 0.343

32

0

0

0

0

0

N/A

–

–

Mock

32/32

0

1.32 ± 0.277

0

0

0

2

8

22

0

7.87 × 108

4.66 × 104

chIL-7

30/32

6

2.47 ± 0.438

0

0

0

7

7

18

0

2.54 × 108

0.87 × 104

IBDV vaccine

7/32

78

5.85 ± 0.510

18

5

5

2

2

0

72

5.67 × 103

0.72 × 102

IBDV vaccine + chIL-7 (50 μg)

6/32

81

6.21 ± 0.253

20

5

4

2

1

0

78

0.55 × 103

0.07 × 102

IBDV vaccine + chIL-7 (100 μg)

3/32

91

6.52 ± 0.448

23

5

2

2

0

0

88

0.63 × 102

–

IBDV vaccine + chIL-7 (200 μg)

1/32

97

7.12 ± 0.436

27

3

2

0

0

0

94

0.16 × 102

–

  1. aMortality was recorded during a 5-day-period after virus challenge and presented as number of dead/total number of chickens in each group.
  2. bSurvival rate is defined as the number of chickens surviving viral challenge/the number of chickens in the group.
  3. cB/B ratio is calculated by (bursal weight/body weight) × 1000 and presented as the mean ± SD from each group.
  4. dBursal gross lesions are scored from 0 to 5 based on the severity of bursal involvement at time of euthanasia (0: no lesion; 1: slight change, 2: scattered or partial follicle damage, 3: 50% or less follicle damage, 4: 51–75% follicle damage and 5: 76–100% follicle damage).
  5. eProtection is defined by the number of chickens with a histopathological BF lesion score of 0 and 1/the number of chickens in the group.
  6. fIBDV titers in the bursal tissues (BT) of the immunized chickens measured by the 50% tissue culture infective dose (TCID50) method in DF-1 cells.
  7. gIBDV titers in the nasal secretions (NS) of the immunized chickens measured by TCID50 method in DF-1 cells.