IgM+ and IgT+ B Cell Traffic to the Heart during SAV Infection in Atlantic Salmon

Vaccines

Preben Boysen¹  Erling Olaf Koppang¹  Håvard Bjørgen¹  Hege Lund¹  Anne Flore Bakke¹  Sergey Afanasyev²  Petter Frost³  Aleksei Krasnov⁴ 

[1] Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ullevålsveien 72, 0454 Oslo, Norway;I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Torez 44, 194223 Saint-Petersburg, Russia;MSD Animal Health Innovation AD, Thormøhlens gate 55, 5006 Bergen, Norway;Nofima AS, 1433 Ås Osloveien 1, Norway;

关键词: Atlantic salmon;    B cells;    salmon alphavirus;    in situ hybridization;    IgM sequencing;    transcriptome;   

DOI  :  10.3390/vaccines8030493

来源: DOAJ

【 摘 要 】

B cells of teleost fish differentiate in the head kidney, and spleen, and either remain in the lymphatic organs or move to the blood and peripheral tissues. There is limited knowledge about piscine B cell traffic to sites of vaccination and infection and their functional roles at these sites. In this work, we examined the traffic of B cells in Atlantic salmon challenged with salmonid alphavirus (SAV). In situ hybridization (RNAScope) showed increased numbers of immunoglobin (Ig)M⁺ and IgT⁺ B cells in the heart in response to SAV challenge, with IgM⁺ B cells being most abundant. An increase in IgT⁺ B cells was also evident, indicating a role of IgT⁺ B cells in nonmucosal tissues and systemic viral infections. After infection, B cells were mainly found in the stratum spongiosum of the cardiac ventricle, colocalizing with virus-infected myocardial-like cells. From sequencing the variable region of IgM in the main target organ (heart) and comparing it with a major lymphatic organ (the spleen), co-occurrence in antibody repertoires indicated a transfer of B cells from the spleen to the heart, as well as earlier recruitment of B cells to the heart in vaccinated fish compared to those that were unvaccinated. Transcriptome analyses performed at 21 days post-challenge suggested higher expression of multiple mediators of inflammation and lymphocyte-specific genes in unvaccinated compared to vaccinated fish, in parallel with a massive suppression of genes involved in heart contraction, metabolism, and development of tissue. The adaptive responses to SAV in vaccinated salmon appeared to alleviate the disease. Altogether, these results suggest that migration of B cells from lymphatic organs to sites of infection is an important part of the adaptive immune response of Atlantic salmon to SAV.

【 授权许可】

Unknown