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Determination of anti-phage antibodies in calf sera following application of Escherichia coli and Mannheimia haemolytica-specific bacteriophages

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12 août 2022
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Fig. 1

Sodium dodecyl sulphate–polyacrylamide gel electrophoresis electropherograms with phage proteinsA: Lines 1, 2 and 3 – 25 A2 and A5 phages specific for M. haemolytica strains; B: Lines 1, 2 and 3 –26, 27 and 29 phages specific for E. coli
M –10–240 kDa molecular weight protein ladder
Sodium dodecyl sulphate–polyacrylamide gel electrophoresis electropherograms with phage proteinsA: Lines 1, 2 and 3 – 25 A2 and A5 phages specific for M. haemolytica strains; B: Lines 1, 2 and 3 –26, 27 and 29 phages specific for E. coli M –10–240 kDa molecular weight protein ladder

Fig. 2

Two-dimensional electrophoresis of phage proteinsA – phages specific for M. haemolytica; B – phages specific for E. coli
M – 7–240 kDa molecular weight standard
Two-dimensional electrophoresis of phage proteinsA – phages specific for M. haemolytica; B – phages specific for E. coli M – 7–240 kDa molecular weight standard

Average absorbance values (±standard deviation) measured in serum samples from calves by ELISA in response to application of bacteriophages specific for E_ coli and M_ haemolytica

Parameter FBS Calves with clinical signs of disease after phage application Healthy calves after phage application Healthy calves not treated with phages

IgG IgM IgA IgG IgM IgA IgG IgM IgA IgG IgM IgA
Mean level of antibodies against whole M. haemolytica and E. coli bacteriophages 0.007 ± 0.004 0.008 ± 0.006 0.001 ± 0.0009 0.64 ± 0.09ab 0.192 ± 0.068ab 0.114 ± 0.048ab 0.845 ± 0.111ab 0.239 ± 0.082ab 0.021 ± 0.007a 0.056 ± 0.024a 0.019 ± 0.00a 0.017 ± 0.01a
Mean level of antibodies against whole E. coli phages 0.0032 ± 0.001 0.014 ± 0.008 0.001 ± 0.0008 0.74 ± 0.16ab 0.211 ± 0.052ab 0.19 ± 0.09ab 0.71 ± 0.13ab 0.203 ± 0.2ab 0.029 ± 0.003a 0.06 ± 0.009a 0.096 ± 0.038a 0.02 ± 0.007a
Mean level of antibodies against whole M. haemolytica phages 0.005 ± 0.004 0.004 ± 0.0001 0.002 ± 0.0005 0.95 ± 0.08ab 0.99 ± 0.111ab 0.23 ± 0.005ab 0.6 ± 0.1a 0.33 ± 0.02ab 0.02 ± 0.002a 0.72 ± 0.017a 0.08 ± 0.03a 0.03 ± 0.001a
Mean level of antibodies against M. haemolytica and E. coli extracted proteins 0.005 ± 0.003 0.009 ± 0.007 0.001 ± 0.0005 0.71 ± 0.134ab 0.18 ± 0.34ab 0.15 ± 0.05ab 0.53 ± 0.13ab 0.226 ± 0.13ab 0.03 ± 0.016 0.06 ± 0.01a 0.07 ± 0.04a 0.02 ± 0.0009a
Mean level of antibodies against E. coli extracted proteins 0.004 ± 0.003 0.002 ± 0.0009 0.001 ± 0.0001 0.83 ± 0.032ab 0.21 ± 0.004ab 0.201 ± 0.002ab 0.68 ± 0.15ab 0.21 ± 0.004ab 0.099 ± 0.007a 0.062 ± 0.001a 0.042 ± 0.002a 0.02 ± 0.008a
Mean level of antibodies against M. haemolytica extracted proteins 0.007 ± 0.004 0.004 ± 0.002 0.001 ± 0.000 0.77 ± 0.13ab 0.3 ± 0.04ab 0.15 ± 0.03ab 0.65 ± 0.21ab 0.26 ± 0.18 ab 0.05 ± 0.02a 0.071 ± 0.04a 0.05 ± 0.02a 0.03 ± 0.01a

Average values obtained in the phage neutralisation assay

Type of phage solution Mean K ± SD in untreated calves Mean K ± SD in treated calves
E. coli phages 0.0019 ± 0.001 7.28 ± 0.54*
M. haemolytica phages 0.0046 ± 0.003 5.57 ± 1.81*
E. coli extracted proteins 0.00156 ± 0.0004 6.74 ± 0.5*
M. haemolytica extracted proteins 0.0013 ± 0.0005 5.053 ± 1.53*