Live attenuated Edwardsiella ictaluri vaccines enhance the protective innate immune responses of channel catfish B cells

Dev Comp Immunol. 2020 Aug;109:103711. doi: 10.1016/j.dci.2020.103711. Epub 2020 Apr 18.

Abstract

Edwardsiella ictaluri causes enteric septicemia of catfish. Our group developed two E. ictaluri live attenuated vaccines (LAVs). However, their effects on the innate functions of catfish B cells are still unexplored. We evaluated phagocytosis and killing of wild-type (WT) E. ictaluri opsonized with sera from vaccinated fish and the survival of B cells exposed to E. ictaluri strains. We assessed phagocytosis of the opsonized WT at 30 °C and 4 °C. B cells killed the internalized E. ictaluri opsonized with sera from vaccinated fish with LAVs more efficiently than other groups at 30 °C. However, catfish B cells were unable to destroy E. ictaluri at 4 °C. Furthermore, E. ictaluri opsonized with serum from fish exposed to WT induce apoptosis and decreased live B cells numbers. Results indicate that opsonization of E. ictaluri with sera from vaccinated fish enhanced phagocytosis and killing activity in B cells and inhibited apoptotic changes in the infected B cells.

Keywords: Apoptosis; Catfish B cells; Innate functions; Live attenuated vaccines; Opsonization; Protection.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptive Immunity / drug effects
  • Adaptive Immunity / immunology
  • Animals
  • Apoptosis / drug effects
  • Apoptosis / immunology
  • B-Lymphocytes / cytology
  • B-Lymphocytes / immunology*
  • B-Lymphocytes / microbiology
  • Bacterial Vaccines / administration & dosage
  • Bacterial Vaccines / immunology*
  • Catfishes / immunology*
  • Catfishes / microbiology
  • Edwardsiella ictaluri / immunology*
  • Edwardsiella ictaluri / physiology
  • Fish Diseases / immunology*
  • Fish Diseases / microbiology
  • Fish Diseases / prevention & control
  • Host-Pathogen Interactions / drug effects
  • Host-Pathogen Interactions / immunology
  • Immunity, Innate / drug effects
  • Immunity, Innate / immunology*
  • Phagocytosis / drug effects
  • Phagocytosis / immunology
  • Protective Agents / administration & dosage
  • Sepsis / immunology
  • Sepsis / microbiology
  • Sepsis / prevention & control
  • Vaccination / methods
  • Vaccines, Attenuated / administration & dosage
  • Vaccines, Attenuated / immunology

Substances

  • Bacterial Vaccines
  • Protective Agents
  • Vaccines, Attenuated