scholarly journals Elucidating the Functional Roles of Helper and Cytotoxic T Cells in the Cell-Mediated Immune Responses of Olive Flounder (Paralichthys olivaceus)

2021 ◽  
Vol 22 (2) ◽  
pp. 847
Author(s):  
Jae Wook Jung ◽  
Ae Rin Lee ◽  
Jaesung Kim ◽  
Young Rim Kim ◽  
Jassy Mary S. Lazarte ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Immune Responses ◽  
Cytotoxic T Cells ◽  
Paralichthys Olivaceus ◽  
Olive Flounder ◽  
Control Group ◽  
Adaptive Immune ◽  
Cd8 T Lymphocytes ◽  
Olive Flounder Paralichthys Olivaceus

In higher vertebrates, helper and cytotoxic T cells, referred to as CD4 and CD8 T lymphocytes, respectively, are mainly associated with adaptive immunity. The adaptive immune system in teleosts involves T cells equivalent to those found in mammals. We previously generated monoclonal antibodies (mAbs) against olive flounder (Paralichthys olivaceus) CD4 T cells, CD4-1 and CD4-2, and used these to describe the olive flounder’s CD4 Tcell response during a viral infection. In the present study, we successfully produced mAbs against CD8 T lymphocytes and their specificities were confirmed using immuno-blotting, immunofluorescence staining, flow cytometry analysis andreverse transcription polymerase chain reaction (RT-PCR). The results showed that these mAbs are specific for CD8 T lymphocytes. We also investigated variations in CD4 and CD8 T cells populations, and analyzed the expression of immune-related genes expressed by these cells in fish infected with nervous necrosis virus or immunized with thymus dependent and independent antigens. We found that both CD4 and CD8 T lymphocyte populations significantly increased in these fish and Th1-related genes were up-regulated compared to the control group. Collectively, these findings suggest that the CD4 and CD8 T lymphocytes in olive flounder are similar to the helper and cytotoxic T cells found in mammals, and Th1 and cytotoxic immune responses are primarily involved in the early adaptive immune response against extracellular antigens.

scholarly journals Poly (I:C)-Potentiated Vaccination Enhances T Cell Response in Olive Flounder (Paralichthys olivaceus) Providing Protection against Viral Hemorrhagic Septicemia Virus (VHSV)

Vaccines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 482
Author(s):  
Jin Hong Chun ◽  
Jae Wook Jung ◽  
Young Rim Kim ◽  
Jassy Mary S. Lazarte ◽  
Si Won Kim ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Paralichthys Olivaceus ◽  
T Cell Responses ◽  
Olive Flounder ◽  
Poly I:C ◽  
Viral Hemorrhagic Septicemia Virus ◽  
Cell Responses ◽  
Viral Hemorrhagic Septicemia ◽  
Olive Flounder Paralichthys Olivaceus

Viral hemorrhagic septicemia (VHS), caused by viral hemorrhagic septicemia virus (VHSV), is a viral disease affecting teleosts, and is the major cause of virus-related deaths in olive flounder (Paralichthys olivaceus). Research has focused on ways to control VHS, and recently, the use of polyinosinic-polycytidylic acid poly (I:C)-potentiated vaccination has been investigated, whereby fish are injected with poly (I:C) and then with live pathogenic virus, resulting in a significant decrease in VHSV-related mortality. T cell responses were investigated in the present study after vaccinating olive flounder with poly (I:C)-potentiated vaccination to understand the ability of poly (I:C) to induce T cell immunity. Stimulation of T cell responses with the poly (I:C)-potentiated vaccination was confirmed by examining levels of CD3+ T cells, CD4-1+ T cells and CD4-2+ T cells. Higher levels of CD4-2+ T cells were found in vaccinated fish than CD4-1+ T cells, believed to result from a synergistic effect between poly (I:C) administration and pathogenic VHSV immunization. More importantly, the role of CD4-2+ T cells in the antiviral response was clearly evident. The results of this study suggest that the outstanding protection obtained with the poly (I:C)-potentiated vaccination is due to the robust immune response initiated by the CD4-2+ T cells.

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