Table 2 Mean numbers of mast cells (± standard deviation) positive to the different antibodies from 6 uninfected vs 6 infected pike were compared using Student’s t-test. The ratio of positive mast cells was determined by scoring 100 mast cells for each microscopic field (10 fields from each section and 3 sections from each fish)

Immunoglobulin E (IgE)-like receptor FcεRIγ

21.50 ± 2.29

79.57 ± 5.86

22.60

< 0.001

Histamine

22.60 ± 1.91

98.57 ± 0.33

96.08

< 0.001

Interleukin-6

36.37 ± 3.96

61.53 ± 5.80

8.78

< 0.001

Lysozyme

19.67 ± 1.89

80.07 ± 4.04

33.18

< 0.001

Met-enkephalin

23.07 ± 0.66

39.17 ± 2.09

17.97

< 0.001

Piscidin-3

0.53 ± 0.18

12.03 ± 3.83

7.35

< 0.001

Serotonin

17.47 ± 1.59

56.70 ± 1.85

39.37

< 0.001

Substance P

49.97 ± 3.95

66.03 ± 3.54

7.42

< 0.001

Tumor necrosis factor (TNF-α)

20.20 ± 1.43

71.27 ± 2.79

39.90

< 0.001