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Xing J, Hu Y, Liu W, Tang X, Sheng X, Chi H, Zhan W. The interaction between the costimulatory molecules CD80/86 and CD28 contributed to CD4 + T lymphocyte activation in flounder (Paralichthys olivaceus). FISH & SHELLFISH IMMUNOLOGY 2024; 148:109482. [PMID: 38458503 DOI: 10.1016/j.fsi.2024.109482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 03/10/2024]
Abstract
CD28 and CD80/86 are crucial co-stimulatory molecules for the T cell activation. Previous study illustrated that CD28 and CD80/86 present on T cells and antigen-presenting cells in flounder (Paralichthys olivaceus), respectively. The co-stimulatory molecules were closely associated with cell immunity. In this paper, recombinant protein of flounder CD80/86 (rCD80/86) and phytohemagglutinin (PHA) were added to peripheral blood leukocytes (PBLs) in vitro. Lymphocytes were significantly proliferated with CFSE staining, and the proportion of CD4+ and CD28+ lymphocytes significantly increased. In the meantime, genes related to the CD28-CD80/86 signaling pathway or T cell markers were significantly upregulated (p < 0.05). For further study, the interaction between CD80/86 and CD28 was confirmed. The plasmid of CD28 (pCD28-FLAG and pVN-CD28) or CD80/86 (pVC-CD80/86) was successfully constructed. In addition, pVN-ΔCD28 without the conserved motif "TFPPPF" was constructed. The results showed that bands of pCD28-FLAG bound to rCD80/86 were detected by both anti-FLAG and anti-CD80/86. pVN-CD28 complemented to pVC-CD80/86 showing positive fluorescent signals, and pVN-ΔCD28 failed to combine with pVC-CD80/86. The motif "TFPPPF" in CD28 played a crucial role in this linkage. These results indicate that CD28 and CD80/86 molecules interact with each other, and their binding may modulate T lymphocytes immune response in flounder. This study proved the existence of CD28-CD80/86 signaling pathway in flounder.
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Affiliation(s)
- Jing Xing
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao, 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
| | - Yujie Hu
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao, 266003, China
| | - Wenjing Liu
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao, 266003, China
| | - Xiaoqian Tang
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao, 266003, China
| | - Xiuzhen Sheng
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao, 266003, China
| | - Heng Chi
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao, 266003, China
| | - Wenbin Zhan
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, Qingdao, 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.
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High-resolution crystal structure of LpqH, an immunomodulatory surface lipoprotein of Mycobacterium tuberculosis reveals a distinct fold and a conserved cleft on its surface. Int J Biol Macromol 2022; 210:494-503. [PMID: 35504420 DOI: 10.1016/j.ijbiomac.2022.04.196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 04/07/2022] [Accepted: 04/26/2022] [Indexed: 11/22/2022]
Abstract
Tuberculosis, caused by Mycobacterium tuberculosis, is predominantly a disease of the lungs acquired by inhaling mycobacteria from infected individuals via airborne droplets. In order to facilitate their entry into the alveolar macrophages, mycobacteria have a collection of pathogen-associated molecular patterns (PAMPs) on their surface that are known to detect certain pattern recognition receptors present on the surface of host cells. A major group of these PAMPs includes mycobacterial lipoproteins, of which, the 19 kDa surface antigen LpqH, has been reported to play a critical role in both host-pathogen interactions as well as pleiotropic immune regulation. Despite its crucial involvement in tuberculosis, the detailed structure-function relationship of this protein remains to be explored. Here, we report the high-resolution crystal structure of the non-acylated LpqH (LpqH48-159) at a resolution of 1.26 Å, which adopts a unique fold. Flow cytometry-based experiments show that the protein can bind and induce apoptosis in PMA-activated human monocytic cell line THP-1, indicative of the preservation of functionality of the protein. Furthermore, analysis of conservation of LpqH sequences from Mycobacterium species reveals a patch of conserved residues on the surface which may play a role in its binding partner recognition and hence in host-pathogen interaction.
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Liu W, Xing J, Tang X, Sheng X, Chi H, Zhan W. Characterization of Co-Stimulatory Ligand CD80/86 and Its Effect as a Molecular Adjuvant on DNA Vaccine Against Vibrio anguillarum in Flounder ( Paralichthys olivaceus). Front Immunol 2022; 13:881753. [PMID: 35619706 PMCID: PMC9127221 DOI: 10.3389/fimmu.2022.881753] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 04/08/2022] [Indexed: 11/15/2022] Open
Abstract
The CD80/86 molecule is one of the important co-stimulatory ligands and involves antigen-specific immune responses by ligating with CD28 and then delivering the required second signal to T-cell activation. In this study, a CD80/86 homolog was identified, and its expression characteristics were studied in flounder (Paralichthys olivaceus). The open reading frame (ORF) of CD80/86 is 906 bp, encoding 301 aa, and the extracellular amino acid sequence encoded two IgV- and IgC-like structural domains; fCD80/86 is highly expressed in head kidney, peripheral blood leukocytes (PBLs), and spleen, and has relatively high expression in muscle. Antibodies specific for CD80/86 were produced, and CD80/86 was colocalized with MHCII+, CD40+, and CD83+ leukocytes but not with IgM+, CD3+, or CD4+ lymphocytes. The cloned CD80/86 in flounder shares conserved structural features with its mammalian counterparts and is mainly distributed on antigen-presenting cells. Based on these data, CD80/86 as an adjuvant to enhance the immune response of DNA vaccine was investigated. A bicistronic DNA vaccine expressing both CD80/86 and the outer membrane protein (OmpK) of Vibrio anguillarum (p-OmpK-CD80/86) was successfully constructed. After immunization, p-OmpK-CD80/86 could induce the upregulation of the proportion of IgM+ and CD4+ cells in flounder, compared to the p-OmpK- or p-CD80/86-immunized group; CD28 genes were significantly induced in the p-CD80/86 and p-OmpK-CD80/86 groups. Compared to the p-OmpK group, the higher expression of CD83, MHCI, CD4, CD8, and IL-2 was detected at the injection site. The relative percent survival (RPS) produced by p-OmpK-CD80/86 is 66.11% following the V. anguillarum challenge, while the RPS of p-OmpK or p-CD80/86 is 46.30% and 5.56%, respectively. The results revealed that CD80/86 is mainly found in antigen-presenting cells, and could help elicit humoral immune responses in teleost through the CD80/86-CD28 signaling pathway involving CD4+ lymphocytes.
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Affiliation(s)
- Wenjing Liu
- Laboratory of Pathology and Immunology of Aquatic Animals, Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao, China
| | - Jing Xing
- Laboratory of Pathology and Immunology of Aquatic Animals, Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xiaoqian Tang
- Laboratory of Pathology and Immunology of Aquatic Animals, Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xiuzhen Sheng
- Laboratory of Pathology and Immunology of Aquatic Animals, Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao, China
| | - Heng Chi
- Laboratory of Pathology and Immunology of Aquatic Animals, Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao, China
| | - Wenbin Zhan
- Laboratory of Pathology and Immunology of Aquatic Animals, Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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Lankipalli S, H S MS, Selvam D, Samanta D, Nair D, Ramagopal UA. Cryptic association of B7-2 molecules and its implication for clustering. Protein Sci 2021; 30:1958-1973. [PMID: 34191384 PMCID: PMC8376414 DOI: 10.1002/pro.4151] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 12/23/2022]
Abstract
T-cell co-stimulation through CD28/CTLA4:B7-1/B7-2 axis is one of the extensively studied pathways that resulted in the discovery of several FDA-approved drugs for autoimmunity and cancer. However, many aspects of the signaling mechanism remain elusive, including oligomeric association and clustering of B7-2 on the cell surface. Here, we describe the structure of the IgV domain of B7-2 and its cryptic association into 1D arrays that appear to represent the pre-signaling state of B7-2 on the cell membrane. Super-resolution microscopy experiments on heterologous cells expressing B7-2 and B7-1 suggest, B7-2 form relatively elongated and larger clusters compared to B7-1. The sequence and structural comparison of other B7 family members, B7-1:CTLA4 and B7-2:CTLA-4 complex structures, support our view that the observed B7-2 1D zipper array is physiologically important. This observed 1D zipper-like array also provides an explanation for its clustering, and upright orientation on the cell surface, and avoidance of spurious signaling.
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Affiliation(s)
- Swetha Lankipalli
- Biological Sciences DivisionPoornaprajna Institute of Scientific Research (PPISR)BengaluruIndia
- Manipal Academy of Higher EducationManipalKarnatakaIndia
| | | | - Deepak Selvam
- Jawaharlal Nehru Center for Advance Scientific ResearchBengaluruKarnatakaIndia
- National Institute for Research in TuberculosisChennaiIndia
| | - Dibyendu Samanta
- School of Bioscience, Sir J. C. Bose Laboratory ComplexIndian Institute of Technology KharagpurKharagpurIndia
| | - Deepak Nair
- Centre for NeuroscienceIndian Institute of ScienceBangaloreIndia
| | - Udupi A. Ramagopal
- Biological Sciences DivisionPoornaprajna Institute of Scientific Research (PPISR)BengaluruIndia
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