Sadeyen JR1Kaiser P2Stevens MP2Dziva F3. 2015. Vaccine. 33(31):3624-7. doi: 10.1016/j.vaccine.2015.06.034. Epub 2015 Jun 16.

  • 1Avian Infectious Diseases Programme, The Pirbright Institute, Compton RG20 7NN, Berkshire, United Kingdom.
  • 2The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, United Kingdom.
  • 3Avian Infectious Diseases Programme, The Pirbright Institute, Compton RG20 7NN, Berkshire, United Kingdom. Electronic address: francis.dziva@sta.uwi.edu.

Abstract

Avian pathogenic Escherichia coli (APEC) exert substantial economic costs on poultry producers worldwide. Vaccination is an attractive method of control, but the immunological basis of protection is poorly understood. Here, we examine the effect of intramuscular injection of cyclophosphamide or saline on homologous protection induced by licensed inactivated or live-attenuated APEC O78 vaccines in chickens. In saline-treated birds,  In cyclophosphamide-treated birds, B cells were severely depleted whereas percentages of circulating CD4- and CD8-positive T cells were normal as detected by flow cytometry. Further, such birds did not produce APEC-specific IgY and were as susceptible to challenge as age-matched unvaccinated controls. The data indicate that homologous protection conferred by licensed APEC vaccines strictly requires a cyclophosphamide-sensitive cell population that includes B cells.

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KEYWORDS:

APEC; Antibody; Bursectomy; Chicken; Cyclophosphamide; Vaccination