Location: Warmwater Aquaculture Research UnitTitle: Catfish lymphocytes expressing CC41-reactive Leukocyte Immune-Type Receptors (LITRs) proliferate in response to Edwardsiella ictaluri infection in vitro
|BLACKMON, LAURA - University Of Mississippi Medical Center|
|WILSON, MELANIE - University Of Mississippi Medical Center|
|BENGTEN, EVA - University Of Mississippi Medical Center|
Submitted to: Developmental and Comparative Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2020
Publication Date: 1/8/2020
Citation: Blackmon, L.L., Quiniou, S., Wilson, M., Bengten, E. 2020. Catfish lymphocytes expressing CC41-reactive Leukocyte Immune-Type Receptors (LITRs) proliferate in response to Edwardsiella ictaluri infection in vitro. Developmental and Comparative Immunology. 106:103610.
Interpretive Summary: Fish possess a unique family of proteins that are not found in mammals. These proteins are called Leukocyte Immune Type Receptors (LITRs) and are involved in immunity. In order to study their role during immune responses, an in vitro assay was developed. This assay revealed that when macrophages were infected with a prominent catfish pathogen, Edwardsiella ictaluri, increased numbers of LITRs were present on the surface of blood lymphocytes. These results show that LITRs are involved in the immune response to Edwardsiella ictaluri, the causative agent of Enteric Septicemia in catfish. This new assay will be instrumental to characterize and understand immune responses to pathogens in fish.
Technical Abstract: Monoclonal antibodies (mAb) CC34 and CC41 recognize overlapping subsets of Leukocyte Immune Type Receptors (LITRs). mAb CC34 was raised against clonal TS32.15 CTL and mAb CC41 was raised against clonal NK cell line. In this study, an in vitro model was developed to monitor CC34- and CC41-reactive cells in response to Edwardsiella ictaluri infection. Briefly, head kidney leukocytes and peripheral blood lymphocytes (PBL) were isolated from individual catfish and labeled with CellTrace Violet and CellTrace FarRed, respectively. The head kidney derived macrophages were infected overnight with E. ictaluri and then co-cultured with autologous PBL. The combined cell cultures were then analyzed using flow cytometry. A significant increase in CC41 staining was observed in the PBL population at 2, 5 and 7 days after culture, which suggest that LITRs are involved in cell-mediated immunity to E. ictaluri.