Developmental and comparative immunology最新文献

What are the future directions of the fields of developmental and comparative immunology? In thinking through this question as I write, I find myself marvelling at the very long ways that we have come since I began as a PhD student some 50 years ago. I think that we cannot know what technical and theoretical advances will emerge in the future, nor will our initial aims survive the realities of what appears in our sights, often from unexpected directions. I feel that we should not allow what we already know about some well-studied systems to blind us to the wide range of possibilities, and that remaining a humble seeker helps the uptake of new realities. Finally, it would be good to try answering the whole range of questions about developmental and comparative immunology, from what to how to why.

In this study, heavy chain genes of IgD and IgT were sequenced and characterized their gene expression in rock bream (Oplegnathus fasciatus). Rock bream (RB)-IgD cDNA is 3319 bp in length and encodes a leader region, variable domains, a μ1 domain, and seven constant domains (CH1–CH7). A membrane-bound (mIgT) and secretory form (sIgT) of RB-IgT cDNAs are 1902 bp and 1689 bp in length, respectively, and encode a leader region, variable domains, four constant domains (CH1–CH4) and C-terminus. Their predicted 3D-structure and phylogenetic relation were similar to those of other teleost. In healthy fish, RB-IgD and mIgT gene expressions were higher in major lymphoid organs and blood, while RB-sIgT gene was more highly expressed in midgut. IgT expressing cells were detected in melano-macrophage centers (MMC) of head kidney in immunohistochemistry analysis. Under immune stimulation in vitro, RB-IgD and IgT gene expressions were upregulated in head kidney and spleen cells by bovine serum albumin or a rock bream iridovirus (RBIV) vaccine. In vivo, their expressions were significantly upregulated in head kidney, blood, and gill upon vaccination. Especially, RB-mIgT gene expression in head kidney and blood was upregulated at day 3 after vaccination while upregulated at earlier time point of day 1 by challenge with RBIV. This may suggest that memory cells might be produced during the primary response by vaccination and rapidly proliferated by secondary immune response by viral infection. RB-sIgT gene expression was highly upregulated in peripheral blood in vaccinated fish after viral infection, indicating that IgT plays an important role in systemic immune response as well as mucosal immune system. Our findings provide information on the role of RB-IgT in adaptive immunity during vaccination and viral infection in the vaccinated fish.

Grass carp (Ctenopharyngodon idella), crucial to global inland aquaculture with a production of 5.8 million tones in 2020, faces significant challenges from hemorrhagic disease caused by grass carp reovirus (GCRV). Rapid mutations compromise current vaccines, underscoring the need for a deeper understanding of antiviral mechanisms to enhance molecular marker-assisted selection. This study investigates the role of Tripartite Motif (TRIM) family in the innate immune response of grass carp, focusing on TRIM103 from Ctenopharyngodon Idella (CiTRIM103), a member of the TRIM-B30.2 family, which includes proteins with the B30.2 domain at the N-terminus, known for antiviral properties in teleosts. CiTRIM103 bind to the outer coat proteins VP5 and VP7 of GCRV. This binding is theorized to strengthen the function of the RIG-I-like Receptor (RLR) signaling pathway, crucial for antiviral responses. Demonstrations using overexpression and RNA interference (RNAi) techniques have shown that CiTRIM103 effectively inhibits GCRV replication. Moreover, molecular docking and pulldown assays suggest potential binding interactions of CiTRIM103's B30.2 domain with GCRV outer coat proteins VP5 and VP7. These interactions impede viral replication, enhance RLR receptor expression, and activate key transcription factors to induce type I interferons (IFNs). These findings elucidate the antiviral mechanisms of CiTRIM103, provide a foundation for future Molecular genetic breeding in grass carp.

« Prediction is very difficult, especially if it is about the future of comparative immunology” could one say to paraphrase Niels Bohr. Yet, if one avoids mistakes of the past and fashions, if one remains ready to welcome surprises an do not to get drowned in big data while profiting from new technologies, if one keeps common sense between expanding and restricting one's scope of investigation in front of the enormous diversity of the tree of life, comparative immunologists are going, in new areas of research and with new tools, to keep contributing enormously to immunology. They will reveal, with the eyes open to homologies and analogies among multiple species, more variations on the theme of immunity and will put the human immune system in perspective a necessary situation to face the questions that remain to be answered in order to improve health or to understand evolution of immune systems. There will always be room in comparative immunology for fundamental approaches to these subjects. A proper education, aimed at combining competences, will be essential to achieve these goals.

Signal Recognition Particle 54 kDa (SRP54) is a subunit of the signal recognition particle (SRP), a cytoplasmic ribonucleoprotein complex guiding the transportation of newly synthesized proteins from polyribosomes to endoplasmic reticulum. In mammals, it has been reported to regulate the RLR signaling pathway negatively by impairing the association between MAVS and MDA5/RIG-I. However, the role of SRP54 in teleost antiviral innate immune response remains obscure. In this study, the SRP54 homolog of black carp (bcSRP54) has been cloned, and its function in antiviral innate immunity has been elucidated. The CDS of bcSRP54 gene consists of 1515 nucleotides and encodes 504 amino acids. Immunofluorescence (IF) showed that bcSRP54 was mainly distributed in the cytoplasm. Overexpressed bcSRP54 significantly reduced bcMDA5-mediated transcription of interferon (IFN) promoter in reporter assay. Co-expression of bcSRP54 and bcMDA5 significantly suppressed bcMDA5-mediated IFN signaling and antiviral activity, while bcSRP54 knockdown increased the antiviral ability of host cells. In addition, the results of the immunofluorescence staining demonstrated the subcellular overlapping between bcSRP54 and bcMDA5, and the co-immunoprecipitation (co-IP) experiment identified their association. Furthermore, the over-expression of bcSRP54 did not influence the protein expression and ubiquitination modification level of bcMDA5, however, hindered the binding of bcMDA5 to bcMAVS. In summary, our results conclude that bcSRP54 targets bcMDA5 and inhibits the interaction between bcMDA5 and bcMAVS, thereby negatively regulating antiviral innate immunity, which provides insight into how teleost SRP54 regulates IFN signaling.

Dragon fruit oligosaccharide (DFO) is an indigestible prebiotic that enhances the growth and reproduction of Daphnia magna, increases the expression of genes involved in immunity, and reduces oxidative stress. This study investigated the effects of DFO on the expression of innate immunity- (Toll, Pelle, proPO, A2M, and CTL), oxidative stress- (Mn-SOD), and nitric oxide (NO) synthesis-related genes (NOS1, NOS2, and arginase) as well as NO localization and number of hemocytes in D. magna. For this ten-day-old D. magna were treated with 0 or 9 mg l⁻¹ of DFO for 24 and 85 h. Gene expression levels, NO intensity and localization, and total hemocytes were evaluated. After 24 h, the expression of Toll and proPO increased significantly (p < 0.05), while that of C-type lectins (CTL) was reduced (p < 0.05). At 85 h, Mn-SOD and CTL expressions were markedly suppressed (p < 0.05). NO was mostly localized in the foregut, midgut, hindgut, and carapace. The expression of NOS1 was reduced after 24 h (p < 0.05). In addition, NO intensity at 24 h was insignificantly lower than the control (p > 0.05). At 85 h, the expression of NOS1, NOS2, and arginase was higher than control, but NO intensity did not differ significantly (p > 0.05). Furthermore, the total hemocyte count elevated remarkably at 85 h (p < 0.05). Our study suggested that 9 mg l⁻¹ of DFO could alter the expression of the genes related to innate immunity, oxidative stress, and NO synthesis in D. magna and significantly stimulate hemocyte production.

The pathogen recognition system involves receptors and genes that play a crucial role in activating innate immune response in brown-marbled grouper (Epinephelus fuscoguttatus) as a control agent against various infections including vibriosis. Here, we report the molecular cloning of partial open reading frames, sequences characterization, and expression profiles of Pattern Recognition Receptors (PRRs) in brown-marbled grouper. The PRRs, namely pglyrp5, tlr5, ctlD, and ctlE in brown-marbled grouper, possess conserved domains and showed shared evolutionary relationships with other fishes, humans, mammals, birds, reptilians, amphibians, and insects. In infection experiments, up to 50% mortality was found in brown-marbled grouper fingerlings infected with Vibrio alginolyticus compared to 27% mortality infected Vibrio parahaemolyticus and 100% survival of control groups. It is also demonstrated that all four PRRs had higher expression in samples infected with V. alginolyticus compared to V. parahaemolyticus. This PRRs gene expression analysis revealed that all four PRRs expressed rapidly at 4-h post-inoculation even though the Vibrio count was only detected earliest at 12-h post-inoculation in samples. The highest expression recorded was from V. alginolyticus inoculated fish spleen with up to 73-fold change for pglyrp5 gene, followed by 14 to 38-fold expression for the same treatment in spleen, head kidney, and blood samples for other PRRs, namely tlr5, ctlD, and ctlE genes. Meanwhile less than a 10% increase in expression of all four genes was detected in spleen, head kidney, and blood samples inoculated with V. parahaemolyticus. These findings indicated that pglyrp5, tlr5, ctlD, and ctlE play important roles in the early immune response to vibriosis infected, brown-marbled grouper fingerlings.

Chickens are a species with a high number of γδ T cells in various tissues. Despite their abundance, γδ T cells are poorly characterized in chickens, partially due to a lack of specific reagents to characterize these cells. Up until now, the TCR1 clone has been the only γδ T cell-specific monoclonal antibody (mAb) in chickens and additional reagents for γδ T cell subsets are needed. In order to address this issue, new mAb were generated in our laboratory by immunizing mice with in vitro cultured γδ T cells. In an initial flow cytometric screen a new mAb, clone “8D2”, displayed an interesting staining pattern that mirrored γδ TCR up- and downregulation in the γδ T cell line D4 over time, prompting us to characterize this antibody further. We compared the expression of the unknown 8D2 epitope in combination with TCR1 staining across various primary cells. In splenocytes, peripheral blood lymphocytes and intestinal epithelial cells, 8D2 consistently labeled a subset of TCR1⁺ cells. To determine, whether specific γδ T cell receptors were recognized by 8D2, we sorted γδ T cells according to their 8D2 and TCR1 expression and analyzed their TCR V(D)J gene usage by TCR profiling. Strikingly, sorted 8D2⁺ cells preferentially expressed Vγ3 genes, whereas the TCR Vγ genes used by TCR1⁺ 8D2^- cells were more variable. γδ TCR in 8D2⁺ cells were most frequently comprised of gamma chain VJ genes TRGV3-8 and TRGJ3, and delta chain VDJ genes TRDV1-2, TRDD2, TRDJ1. To confirm binding of 8D2 to specific γδ TCR, the preferentially utilized combination of TRG and TRD was expressed in HEK293 cells in combination with CD3, demonstrating surface binding of the 8D2 mAb to this Vγ3 γδ TCR-expressing cell line. Conversely, HEK293 cells expressing either Vγ1 or Vγ2 TCR did not react with 8D2. In conclusion, 8D2 is a novel tool for identifying specific Vγ3 bearing γδ T cells.