Involvement of CD4-1 T cells in the cellular immune response of olive flounder (Paralichthys olivaceus) against viral hemorrhagic septicemia virus (VHSV) and nervous necrosis virus (NNV) infection

Betanodavirus and VER Disease: A 30-year Research Review

“…Regarding the cell immune response to betanodavirus infection, an increase in the expression of T-cell marker genes (TRCb, CD4-2, CD4, CD8a, CB8b, Lck, NCCRP-1 and ZAP-70) has been reported in infected Atlantic halibut, European sea bass and gilthead sea bream [213,214,224,225]. In addition, the proliferation of CD4-1-positive lymphocytes has been assessed by flow cytometry in infected olive flounder (Paralichthys olivaceus) [226].…”

Characterization of CD4-Positive Lymphocytes in the Antiviral Response of Olive Flounder (Paralichthys oliveceus) to Nervous Necrosis Virus

“…In vertebrates, the adaptive immune system is mostly mediated by the two major subsets of T lymphocytes, helper and cytotoxic T cells, defined by their expression of CD4 and CD8 glycoproteins, respectively [1,2]. Mammalian CD4-positive T cells regulate the immune responses of the host defense [3].…”

“…The CD4 molecules, which are involved in T cell development and activation, are significant cell surface markers used for identifying helper T cell subsets [4,5]. CD4 helper T cells recognize exogenous pathogens through their interaction with the major histocompatibility complex (MHC) class II molecules expressed on antigen presenting cells (APCs), such as dendritic cells and macrophages [1]. Identification of their function in teleost fish has suggested that fish CD4 helper T cells possess a similar role to mammalian helper T cells.…”

“…In teleosts, two types of CD4-like molecules, CD4-1 and CD4-2, have been reported in fugu (Takifugu rubripes), rainbow trout (Oncorhynchus mykiss), carp (Cyprius carpio), sea bass (Dicentrarchus labrax) and Atlantic salmon (Salmo salar) [6][7][8][9][10][11]. Structurally, mammalian CD4 is a membrane glycoprotein with an estimated molecular mass of~55 kDa that is composed of four immunoglobulin (Ig)-like extracellular domains (D1-D4), a transmembrane domain and a cytoplasmic tail [1,11,12]. Teleost CD4, referred to as CD4-1, is present similar to mammalian CD4 molecules, whereas the second CD4 homologue, designated CD4-2, contains two or three Ig-like domains [6][7][8]11].…”

“…Monoclonal antibodies (mAbs) against cell surface markers are one of the most frequently used tools for characterizing mammalian leukocytes, and these are also used for a variety of research and therapeutic applications [1,14]. Although the number of studies characterizing components of the immune response of teleosts is increasing, studies investigating T cell populations and their function are hindered by the lack of specific mAbs for characterizing target T cells [11,[14][15][16].…”