title: DNA vaccination against a fish rhabdovirus promotes an early chemokine-related recruitment of B cells to the muscle.
abstract: In fish, intramuscular (i.m) injection of plasmid DNA encoding viral proteins has proved a highly effective vaccination strategy against some viral pathogens. The efficacy of DNA vaccination in teleost fish is based on the high level of viral antigen expression in muscle cells inducing a strong and long-lasting protection. However, the mechanisms through which this protection is established and effectuated in fish are still not fully understood. Moreover, similarities to mammalian models cannot be established since DNA vaccination in mammals usually induces much weaker responses. In this work, we have focused on the characterization of the immune cells that infiltrate the muscle at the site of DNA injection in vaccinated fish and the chemokines and chemokine receptors that may be involved in their infiltration. We have demonstrated through diverse techniques that B lymphocytes, both IgM⁺ and IgT⁺ cells, represented a major infiltrating cell type in fish vaccinated with a viral haemorrhagic septicaemia virus (VHSV) glycoprotein-encoding DNA vaccine, whereas in control fish injected with an oil adjuvant mainly granulocyte/monocyte-type cells were attracted. Among twelve chemokine genes studied, only CXCL11_L1, CK5B and CK6 mRNA levels were up-regulated in DNA vaccinated fish compared to fish injected with the corresponding vector backbone. Furthermore, the transcription of CXCR3B, a possible receptor for CXCL11_L1 was also significantly up-regulated in vaccinated fish. Finally, experiments performed with recombinant trout CK5B and CK6 and chemokine expression plasmids revealed that these chemokines have chemotactic capacities which might explain the recruitment of B cells to the site of DNA injection. Altogether, our results reveal that there is an early chemokine-related B cell recruitment triggered by i.m. DNA vaccination against VHSV which might play an important role in the initial phase of the immune response.
authors.affiliation: Centro de Investigación en Sanidad Animal (CISA-INIA), Valdeolmos, Madrid, Spain.
authors.forename: Rosario
authors.initials: R
authors.lastname: Castro
authors.affiliation: Centro de Investigación en Sanidad Animal (CISA-INIA), Valdeolmos, Madrid, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Martínez-Alonso
authors.affiliation: Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Insel Riems, Greifswald, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Fischer
authors.affiliation: Área de Biología Celular, Universidad de León, León, Spain.
authors.forename: Neila Álvarez de
authors.initials: NÁ
authors.lastname: Haro
authors.affiliation: Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Insel Riems, Greifswald, Germany.
authors.forename: Verónica
authors.initials: V
authors.lastname: Soto-Lampe
authors.affiliation: Scottish Fish Immunology Research Centre, University of Aberdeen, Aberdeen, UK.
authors.forename: Tiehui
authors.initials: T
authors.lastname: Wang
authors.affiliation: Scottish Fish Immunology Research Centre, University of Aberdeen, Aberdeen, UK.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Secombes
authors.affiliation: Department of Animal Science, Aarhus University, DK-8200 Aarhus, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Lorenzen
authors.affiliation: Department of Animal Science, Aarhus University, DK-8200 Aarhus, Denmark.
authors.forename: Ellen
authors.initials: E
authors.lastname: Lorenzen
authors.affiliation: Centro de Investigación en Sanidad Animal (CISA-INIA), Valdeolmos, Madrid, Spain. Electronic address: tafalla@inia.es.
authors.forename: Carolina
authors.initials: C
authors.lastname: Tafalla
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D018925:Chemokines / Q000276:immunology*; D031941:Hemorrhagic Septicemia, Viral / Q000276:immunology / Q000517:prevention & control*; D007273:Injections, Intramuscular; D009132:Muscles / Q000276:immunology; D029141:Novirhabdovirus; D017686:Oncorhynchus mykiss / Q000276:immunology / Q000821:virology; D019444:Vaccines, DNA / Q000276:immunology*; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D018925:Chemokines; D019444:Vaccines, DNA; D014765:Viral Vaccines
keywords: B cells; Chemokine receptors; Chemokines; DNA vaccine; Teleost fish; Viral haemorrhagic septicaemia virus (VHSV)