Veterinary Research最新文献

{"title":"Atypical Actinobacillus pleuropneumoniae serotype 12 strains with a higher virulence potential.","authors":"Antony T Vincent, Sonia Lacouture, Guillaume St-Jean, Rodrigo Tapia, Servane Payen, Kon Michiha, Joachim Frey, To Ho, Marcelo Gottschalk","doi":"10.1186/s13567-025-01579-9","DOIUrl":"https://doi.org/10.1186/s13567-025-01579-9","url":null,"abstract":"<p><p>Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia, a disease of major economic impact. Serotype 12 is generally considered to be of low virulence and is typically associated with subclinical infections. However, we describe four atypical serotype 12 field strains recovered from severe clinical outbreaks in Chile. These strains exhibited an unusual toxin gene profile (apxIICA, apxIIICA, apxIBD, apxIIIBD), suggesting the ability to produce both ApxII and ApxIII toxins. Comparative genomic analyses revealed that these atypical strains carry the capsule genes of serotype 12 but the LPS biosynthesis genes of serotype 15, indicating a hybrid genomic structure. Phylogenetic analysis confirmed that they cluster separately from classical serotype 12 strains and are closely related to other atypical strains from Japan, USA, and Canada. Experimental infection in pigs demonstrated significantly increased virulence of the atypical Chilean strain compared to the reference strain of serotype 12, with higher clinical scores, severe lung lesions, and atypical serological responses against serotypes 3/6/8/15/17. These findings challenge the traditional view of serotype 12 as low-virulence and highlight the need for improved diagnostic approaches that incorporate both capsule and LPS profiling. The existence of these atypical strains has important implications for disease surveillance, diagnostics, and vaccine development in swine health management.</p>","PeriodicalId":23658,"journal":{"name":"Veterinary Research","volume":"56 1","pages":"149"},"PeriodicalIF":3.7,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144627214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"African swine fever virus infection of porcine peripheral blood monocyte-derived macrophages induces the formation of tunneling nanotube-connected large vesicle-like cell segments: a potential mechanism for intercellular ASFV trafficking.","authors":"Brecht Droesbeke, Nadège Balmelle, Hans J Nauwynck, Herman Favoreel, Marylène Tignon","doi":"10.1186/s13567-025-01582-0","DOIUrl":"10.1186/s13567-025-01582-0","url":null,"abstract":"<p><p>African swine fever (ASF) is a highly fatal viral disease in pigs, with mortality rates that can reach 100%. The causative agent, African swine fever virus (ASFV), primarily targets cells of the mononuclear phagocytic system (MPS), particularly monocyte-derived macrophages (MDMs). Despite the severity of the disease, there are currently no effective antiviral treatments available in Europe. A significant barrier to therapeutic development is the limited understanding of how ASFV interacts with its primary target cells. A deeper understanding of the morphological changes induced by ASFV in infected cells is crucial to this effort. To address this knowledge gap, we used conventional and confocal immunofluorescence microscopy, as well as transmission electron microscopy, to investigate ASFV-infected primary MDMs. Our analysis revealed that ASFV infection leads to the formation of large cellular protrusions, which are characterized by vesicle-shaped cellular segments (CSs) at their tips. These protrusions contain all major cytoskeletal components, showing characteristics similar to those of tunneling nanotubes (TNTs). In 84.93% of the cases, the nucleus remained in the cell body (CB) near the viral factory. In the remaining cases, the nucleus was found within these CSs, whereas the viral factory was present in the CB. Additionally, 57.6% of the cells were in contact with the CS and distant cells, suggesting a potential mechanism for ASFV transmission. These findings suggest that ASFV induces cellular segmentation linked by TNT-like structures. Further research is needed to better understand the biogenesis and functional significance of these segmented cells, which could inform future strategies for combating ASFV.</p>","PeriodicalId":23658,"journal":{"name":"Veterinary Research","volume":"56 1","pages":"148"},"PeriodicalIF":3.7,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12247315/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144609733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EtSERPIN1 binding with chicken ANXA2 is essential for Eimeria tenella attachment and invasion process.","authors":"Zengbao Wang, Taifeng Li, Yingying Jiang, Xue Wang, Hongmei Li, Xiaomin Zhao, Xiao Zhang, Ningning Zhao","doi":"10.1186/s13567-025-01532-w","DOIUrl":"10.1186/s13567-025-01532-w","url":null,"abstract":"<p><p>Serpin protease inhibitors (SERPIN) in protozoa play crucial roles in various biological processes, including the invasion of host cells. However, the precise roles and molecular mechanisms underlying SERPIN-mediated invasion of parasite remain poorly understand. In this study, we provide evidence that surface-expressed Eimeria tenella SERPIN1 (EtSERPIN1) on sporozoites is involved in adhesion and invasion processes. To elucidate the molecular target responsible for mediating EtSERPIN1-induced invasion, we utilized GST pull-down and yeast two-hybrid assays to identify host cell membrane proteins interacting with EtSERPIN1. Our findings revealed an interaction between EtSERPIN1 and a membrane protein called annexin A2 (ANXA2). Furthermore, recombinant GgANXA2 was shown to bind to the sporozoite surface. Pre-treatment with anti-GgANXA2-specific antibody or recombinant GgANXA2 protein significantly inhibited EtSERPIN1 binding to host cells. Pre-incubation with recombinant GgANXA2 also reduced sporozoite infection in both DF-1 cells and chickens. These results suggest that the interaction between EtSERPIN1 and GgANXA2 plays a critical role in both adhesion and invasion processes of E. tenella sporozoites. Finally, we investigated the impact of recombinant GgANXA2 and EtSERPIN1 proteins on E. tenella infection. Our results demonstrate that incubation with GgANXA2 protein significantly attenuated sporozoite infectivity, as evidenced by a significant reduction in parasite burden within the chicken cecum. Immunization with recombinant EtSERPIN1 exhibited potent anti-E. tenella activity, with higher body weight gains, lower cecal lesions and oocyst output, as well as elevated levels of cecal mucosa antibodies. These findings suggest that targeting GgANXA2 through EtSERPIN1 mediates adhesion and invasion processes of E. tenella, highlighting its potential as a novel therapeutic target.</p>","PeriodicalId":23658,"journal":{"name":"Veterinary Research","volume":"56 1","pages":"147"},"PeriodicalIF":3.7,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12243203/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144609734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanisms of vaccine protection in chickens against challenge with virulent Mycoplasma synoviae.","authors":"Kanishka I Kamathewatta, Anna Kanci Condello, Pollob K Shil, Amir H Noormohammadi, Neil D Young, Glenn F Browning, Kelly A Tivendale, Nadeeka K Wawegama","doi":"10.1186/s13567-025-01571-3","DOIUrl":"10.1186/s13567-025-01571-3","url":null,"abstract":"<p><p>The Vaxsafe MS vaccine is used globally to control infections with Mycoplasma synoviae (MS) in commercial poultry. It provides long-term protective immunity against airsacculitis and tracheitis caused by M. synoviae. However, the mechanisms involved in the protection afforded by the vaccine are not well understood. This study aimed to investigate and compare tracheal mucosal responses to challenge with virulent M. synoviae in chickens vaccinated with Vaxsafe MS and in unvaccinated chickens. The tracheal mucosal transcriptional profiles were obtained using messenger RNA sequencing. Compared to the unvaccinated-unchallenged chickens, 64 genes were differentially transcribed in the vaccinated-challenged chickens and 321 genes were differentially transcribed in the unvaccinated-challenged chickens. In vaccinated-challenged chickens, functional categories enriched with up-regulated genes included IL4 production, TCR signalling (without T-cell co-stimulation), T-cell activation/proliferation/differentiation and B-cell activation/proliferation. In the unvaccinated-challenged chickens, many other functional categories were also enriched with upregulated genes, including Positive regulation of the MAPK/ERK cascades, Positive regulation of IFN gamma production, T-cell co-stimulation, Negative regulation of IL6 production, IL10 production, Toll-like receptor signalling, Neutrophil activation/degranulation, DAP12 signalling, Chemotaxis, Phagocytosis, Cell killing, PD-1 signalling, Negative regulation of non-canonical NF-κB signal transduction, Isotype switching and Somatic diversification of immune receptors. The transcriptional changes in the unvaccinated-challenged chickens were indicative of T-helper-1-cell-mediated inflammation and dysregulated primary T- and B-cell responses, which were absent in the vaccinated-challenged chickens. In the vaccinated-challenged chickens the changes were indicative of a memory T-follicular-helper-cell-dependent secondary B-cell response, suggesting that this response was protective against the dysregulated inflammatory response seen in unvaccinated chickens.</p>","PeriodicalId":23658,"journal":{"name":"Veterinary Research","volume":"56 1","pages":"146"},"PeriodicalIF":3.7,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12243254/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144601673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Blastocystis in free-ranging wild ruminant species across the Iberian Peninsula.","authors":"Ana M Figueiredo, Alejandro Dashti, Jenny G Maloney, Aleksey Molokin, Nadja S George, Pamela C Köster, Begoña Bailo, Ana Sánchez de Las Matas, Miguel Ángel Habela, Antonio Rivero-Juarez, Joaquín Vicente, Emmanuel Serrano, Maria C Arnal, Daniel Fernández de Luco, Patrocinio Morrondo, José A Armenteros, Ana Balseiro, Guillermo A Cardona, Carlos Martínez-Carrasco, Rita T Torres, Carlos Fonseca, Atle Mysterud, João Carvalho, Rafael Calero-Bernal, David González-Barrio, Mónica Santín, David Carmena","doi":"10.1186/s13567-025-01563-3","DOIUrl":"10.1186/s13567-025-01563-3","url":null,"abstract":"<p><p>The growing wild ungulate populations across Europe represents an increasingly important source for the spread of zoonotic pathogens. Blastocystis is a common intestinal protist observed in humans and animals worldwide. Studies on Blastocystis occurrence and subtype (ST) diversity in free-ranging wild ruminants are lacking globally, and more data are needed to understand the epidemiological scenario in wild European ruminants. We collected 833 faecal samples from free-ranging wild ungulates across Spain (n = 699) and Portugal (n = 134) between 1998 and 2021. Using conventional PCR and next-generation amplicon sequencing, Blastocystis was found in 13.8% (115/833; 95% CI: 11.5-16.3) of the wild ruminants analysed. Its occurrence was significantly higher in Portugal (38.1%, 51/134; 95% CI 29.8-46.8) than in Spain (9.2%, 64/699; 95% CI: 7.1-11.5). Fifteen Blastocystis STs, fourteen previously recognised (ST2, ST5, ST10, ST13, ST14, ST21, ST23-ST26, ST30, and ST42-ST44), and one novel (named ST49), were detected among the surveyed wild ruminant populations. Novel ST49 was described using Oxford Nanopore sequencing to produce full-length reference sequences of the small subunit ribosomal RNA gene. A greater ST diversity was observed in Spanish samples. Mixed infections were found in 58.3% (67/115) of the total Blastocystis-positive samples. Our results have enhanced the knowledge regarding Blastocystis occurrence and ST diversity and host preference present in wild ruminants from the Iberian Peninsula, which will assist in clarifying the relationships between the sylvatic and domestic cycles of this protist and may ultimately provide tools to help manage future public health epidemiological scenarios.</p>","PeriodicalId":23658,"journal":{"name":"Veterinary Research","volume":"56 1","pages":"145"},"PeriodicalIF":3.7,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12239363/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144601672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Construction of a replication-defective recombinant virus and cell-based vaccine for H9N2 avian influenza virus.","authors":"Lijin Lai, Rui Li, Yanan Chen, Junyuan Deng, Siyao Yu, Qiuyan Lin, Libin Chen, Tao Ren","doi":"10.1186/s13567-025-01577-x","DOIUrl":"10.1186/s13567-025-01577-x","url":null,"abstract":"<p><p>The H9N2 subtype of avian influenza is highly contagious, and although it is classified as a low-pathogenic avian influenza virus, its tendency to recombine with other subtypes of avian influenza viruses has made it a potential problem for the poultry industry. Vaccines currently used to prevent this disease are all inactivated, making it difficult to stimulate long-lasting immunity, and have a very weak ability to trigger cellular immunity, thus failing to address the problem of virus shedding. Live-attenuated vaccines are capable of stimulating cellular immunity but carry the risk of recombination with wild-type strains. In this study, we successfully rescued a replication-deficient H9N2 strain (H9-SD18GD12HA) using reverse genetic techniques, which was obtained by replacing the neuraminidase (NA) gene with the open reading frame of the hemagglutinin (HA) gene with the PR8 strain as the backbone. Dynamic growth results showed that H9-SD18GD12HA can proliferate only under NA-containing conditions and therefore cannot grow in normal animals or cells. After immunization of chickens with H9-SD18GD12HA using eye and nose drops, both humoral and cellular immunity were stimulated, and some degree of reduction in virus shedding was observed. These results indicate that H9-SD18GD12HA has good immunogenicity, does not proliferate in vivo, and has the potential to be developed into a novel live-attenuated vaccine for the H9N2 subtype of avian influenza.</p>","PeriodicalId":23658,"journal":{"name":"Veterinary Research","volume":"56 1","pages":"144"},"PeriodicalIF":3.7,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12235990/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144592475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Homologous recombination and evolutionary arms race drive the adaptive evolution of African swine fever virus.","authors":"Wenqiang Wang, Qinqiu Liu, Qilin Zhao, Zhenbang Zhu, Wei Wen, Zhendong Zhang, Xiangdong Li","doi":"10.1186/s13567-025-01573-1","DOIUrl":"10.1186/s13567-025-01573-1","url":null,"abstract":"<p><p>African Swine Fever Virus (ASFV) is a highly contagious pathogen responsible for substantial economic losses in swine populations worldwide. Despite extensive research, the mechanisms underlying the genomic evolution of ASFV remain poorly understood. In this study, we conducted a comprehensive analysis of ASFV evolutionary strategies by examining 252 complete ASFV genomes. Our pan-genome analysis categorizes ASFV genes into core and non-core categories, with core genes predominantly locate in the central region of the genome, while non-core genes are primarily situated at the variable genomic termini, exhibiting higher rates of genetic loss and diversification. Gene synteny analysis revealed that ASFV inherited a portion of its core gene repertoire from the common ancestor of the Asfarviridae family, establishing its central genomic framework, and acquired virus-specific genes that contributed to its distinct genetic identity during divergence. Homologous recombination analysis identified 76 genes exhibiting strong recombination signals, emphasizing the critical role of recombination in ASFV evolution. Additionally, 9 genes were found to be under positive selection, highlighting the influence of the host-virus evolutionary arms race in shaping ASFV genome, particularly in terms of immune evasion and host interaction. These findings underscore the dynamic evolutionary forces driving ASFV adaptive evolution and provide important implications for understanding the virus global spread and the development of effective control measures.</p>","PeriodicalId":23658,"journal":{"name":"Veterinary Research","volume":"56 1","pages":"142"},"PeriodicalIF":3.7,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12235792/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144592476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proteomic profiling of dysbiosis-challenged broilers reveals potential blood biomarkers for intestinal health.","authors":"Svitlana Tretiak, Teresa Mendes Maia, Richard Ducatelle, Marc Cherlet, Tom Rijsselaere, Filip Van Immerseel, Francis Impens, Gunther Antonissen","doi":"10.1186/s13567-025-01570-4","DOIUrl":"10.1186/s13567-025-01570-4","url":null,"abstract":"<p><p>The intestinal microbiome forms a dynamic ecosystem whose balanced composition and functioning are essential for maintaining overall gut health and well-being in living organisms. In broilers, dysbiosis disrupts the microbiota-host balance, often without obvious clinical symptoms but with intestinal inflammation, and leads to impaired animal performance. This study aimed to identify host blood-based protein biomarkers that indicate intestinal inflammation and intestinal barrier dysfunction. Using mass spectrometry-based proteomics, blood plasma samples from broilers derived from an in vivo dysbiosis model were analyzed and compared to healthy controls. Microscopic histologic changes in the gut (shortened villi, increased crypt depth) were observed in the duodenal and jejunal tissue of 25-days old challenged birds. Elevated levels of permeability markers faecal ovotransferrin and serum iohexol additionally indicated increased intestinal leakage in the challenged group. The blood plasma proteome analysis enabled quantification of 388 proteins, 25 of which were significantly different between the tested groups. The challenge was marked by activation of immune and signaling pathways, and response to bacteria, while proteins related to cellular physiology, cell-cell communication, and extracellular matrix (ECM) processes were suppressed. Protein-protein interaction analysis revealed two clusters of downregulated proteins involved in ECM organization and cell adhesion. Intestinal dysbiosis in broilers demonstrated that the host prioritizes immune defense over structural maintenance. The activation of immune processes and suppression of ECM pathways highlight potential biomarkers and therapeutic targets. Data are available via ProteomeXchange with identifier PXD056546.</p>","PeriodicalId":23658,"journal":{"name":"Veterinary Research","volume":"56 1","pages":"143"},"PeriodicalIF":3.7,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12235828/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144592477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ferritin-based nanoparticle vaccine protects neonatal piglets against porcine epidemic diarrhea virus challenge following immunization of pregnant sows.","authors":"Yangkun Liu, Jiaxin Deng, Zhen Bi, Mingzhan Luo, Xueying Han, Lunguang Yao","doi":"10.1186/s13567-025-01542-8","DOIUrl":"10.1186/s13567-025-01542-8","url":null,"abstract":"<p><p>Porcine epidemic diarrhea virus (PEDV) is an enteropathogenic coronavirus that causes severe diarrhea and high mortality in neonatal piglets, resulting in significant economic losses to the pig industry worldwide. Given that current commercial vaccines lack adequate protection against variant PEDV strains, there is an urgent need for the development of more effective vaccines to control PEDV infection. Here, a novel nanoparticle vaccine displaying the core neutralizing epitope CO-26 K-equivalent (COE) of PEDV spike protein was developed using Helicobacter pylori ferritin as an antigen delivery system, and its protective efficacy against the highly virulent PEDV LYL strain in suckling piglets was evaluated following immunization of pregnant sows. Compared to the COE monomer vaccines, COE-ferritin nanoparticle vaccines induced higher levels of PEDV-specific IgG, IgA, and neutralizing antibodies in the serum and colostrum of sows. Importantly, 3-day-old piglets born to COE-ferritin nanoparticle vaccinated sows were effectively protected against PEDV challenge, showing no clinical symptoms, less body weight loss, and rapid clearance of the virus in fecal swabs and intestines. Overall, our data demonstrate the protective efficacy of ferritin-based nanoparticles with the PEDV COE antigen, which may be further developed as a vaccine for sows to protect their piglets against PEDV.</p>","PeriodicalId":23658,"journal":{"name":"Veterinary Research","volume":"56 1","pages":"140"},"PeriodicalIF":3.7,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12235928/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144585010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of glycerol phosphate and an immunogenic glycan motif in rhamnose-rich polysaccharides of Streptococcus uberis.","authors":"Yao Shi, Göran Widmalm, Natalia Korotkova, Adrian Molenaar, Mark A Holmes, Scott McDougall, Jetta J E Bijlsma, Nina M van Sorge, Lindert Benedictus","doi":"10.1186/s13567-025-01574-0","DOIUrl":"10.1186/s13567-025-01574-0","url":null,"abstract":"<p><p>Streptococcus uberis is a causative pathogen of bovine mastitis with high genetic diversity. Rhamnose-rich polysaccharides (RPS) are abundant surface structures covalently anchored to peptidoglycan and represent promising vaccine candidates for several streptococcal pathogens. It was previously reported that the RPS of S. uberis strain 233 is composed of a repeating → 2)-α-L-Rhap-(1 → 3)-α-L-Rhap-(1 → disaccharide backbone decorated with α-D-Glcp side-chains. In this study, we identified a hitherto unknown glycerol phosphate (GroP) modification at the 6-OH of the Glc residue in S. uberis 233 RPS using nuclear magnetic resonance analysis. Comparative genomic analysis of 592 S. uberis genomes revealed significant diversity in the RPS biosynthesis gene cluster with six major RPS genotypes. RPS genotypes 1-4, representing 97.5% of the analyzed strains, all contained the rhamnan backbone biosynthesis genes shared between several streptococcal species, as well as a putative GroP transferase gene. Using rhamnan-reactive immune serum, we further demonstrated that rhamnan is a conserved and accessible glycan motif in S. uberis RPS genotype 1 and 2 strains, but this motif is inferred to be shielded by side-chains in genotype 4 strains. Importantly, experiments with sera from cattle, challenged intramammarily with S. uberis, revealed that the rhamnan backbone of S. uberis RPS is an immunogenic glycan motif and remained accessible to bovine IgG antibodies in the presence of single residue RPS side-chains. Overall, this study suggests that S. uberis RPS are modified with GroP and reports that RPS in most strains contain a conserved, immunogenic and antibody accessible rhamnan glycan motif.</p>","PeriodicalId":23658,"journal":{"name":"Veterinary Research","volume":"56 1","pages":"139"},"PeriodicalIF":3.7,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12235971/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144585008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}