Cluster of differentiation antigens: essential roles in the identification of teleost fish T lymphocytes

Abstract

Cluster of differentiation (CD) antigens are cell surface molecules expressed on leukocytes and other cells associated with the immune system. Antibodies that react with CD antigens are known to be one of the most essential tools for identifying leukocyte subpopulations. T lymphocytes, as an important population of leukocytes, play essential roles in the adaptive immune system. Many of the CD antigens expressed on T lymphocytes are used as surface markers for T lymphocyte classification, including CD3, CD4 and CD8 molecules. In this review, we summarize the recent advances in the identification of CD molecules on T lymphocytes in teleosts, with emphasis on the functions of CD markers in the classification of T lymphocyte subsets. We notice that genes encoding CD3, co-receptors CD4 and CD8 have been cloned in several fish species and antibodies have been developed to study protein expression in morphological and functional contexts. T lymphocytes can be divided into CD4+ and CD8+ cells discriminated by the expression of CD4 and CD8 molecules in teleost, which are functionally similar to mammalian helper T cells (Th) and cytotoxic T cells (Tc), respectively. Further studies are still needed on the particular characteristics of teleost T cell repertoires and adaptive responses, and results will facilitate the health management and development of vaccines for fish.

Splenic protection network revealed by transcriptome analysis in inactivated vaccine-immunized flounder (Paralichthys olivaceus) against Edwardsiella tarda infection

“…In mammals, stimulated by different antigens, CD4 + T lymphocytes differentiate into different cell subtypes (Th1, Th2, Th17 and Treg cells). This mechanism has also been demonstrated in teleost fish ( 78 ). Flounder were immunized with the NADP-dependent isocitrate dehydrogenase (IDH) subunit vaccine of E. tarda .…”

Navigating sex and sex roles: deciphering sex-biased gene expression in a species with sex-role reversal (Syngnathus typhle)

“…There was also V-set immunoregulatory receptor ( vsir ), analogous to other immune checkpoint molecules, VSIR (VISTA) plays a role in modulating T cell responses, acting as a negative regulator of T cell activation to prevent excessive immune responses and maintain immune homeostasis (51,52). Additionally, the gene cluster of differentiation (CD) antigens, such as cd7al and cd247l , were identified, which participate in immune recognition processes (53). Notably, recombination activating gene 1 ( rag1 ) was also found upregulated in YMs, encoding a protein crucial for V(D)J recombination, this process is fundamental for generating diverse antigen receptor molecules on immune cells, specifically B and T cells (54,55).…”

“…in particular had a variety of upregulated clusters of differentiation (CD) genes, such as cd7, cd44b, cd209, cd81, cd247, and cd79a (Table 1). CD molecules encode surface proteins on white blood cells that are important in regulating the function of immune cells (Tian et al 2022). M.o.…”

“…There was also V-set immunoregulatory receptor (vsir), analogous to other immune checkpoint molecules, VSIR (VISTA) plays a role in modulating T cell responses, acting as a negative regulator of T cell activation to prevent excessive immune responses and maintain immune homeostasis (51,52). Additionally, the gene cluster of differentiation (CD) antigens, such as cd7al and cd247l, were identified, which participate in immune recognition processes (53).…”

Current status and development prospects of aquatic vaccines

“…Both cellular immunity (including cytotoxicity) and humoral immunity are activated by nucleic acid vaccination. Cellular immunity is primarily initiated by antigen-presenting cells (APCs) such as macrophages and dendritic cells (DCs) ( 312 , 313 ). DNA motifs and mRNA transcripts express immunogenic proteins in fish that simulate infection by intracellular pathogens and allow the presentation of exogenous antigenic peptides on the APC surface via major histocompatibility complex (MHC) class I.…”