Mucosal Immune Responses Research Articles

An intranasal influenza virus vector vaccine protects against Helicobacter pylori in mice.

Helicobacter pylori is a human pathogen that infects almost half of the population. Antibiotic resistance in H. pylori threatens health and increases the demand for prophylactic and therapeutic vaccines. Traditional oral vaccine research faces considerable challenges because of the epithelial barrier, potential enterotoxicity of adjuvants, and the challenging conditions of the gastric environment. We developed an intranasal influenza A virus (IAV) vector vaccine based on two live attenuated influenza viruses with modified acidic polymerase protein (PA) genes encoding the A subunit of H. pylori neutrophil-activating protein (NapA), named IAV-NapA, including influenza virus A/WSN/33 (WSN)-NapA and A/Puerto Rico/8/34 (PR8)-NapA. These recombinant influenza viruses were highly attenuated and exhibited strong immunogenicity in mice. Vaccination with IAV-NapA induced antigen-specific humoral and mucosal immune responses while stimulating robust Th1 and Th17 cell immune responses in mice. Our findings suggest that prophylactic and therapeutic vaccination with influenza virus vector vaccines significantly reduces colonization of H. pylori and inflammation in the stomach of mice.IMPORTANCEHelicobacter pylori is the most common cause of chronic gastritis and leads to severe gastroduodenal pathology in some patients. Many studies have shown that Th1 and Th17 cellular and gastric mucosal immune responses are critical in reducing H. pylori load. IAV vector vaccines can stimulate these immune responses while overcoming potential adjuvant toxicity and antigen dosing issues. To date, no studies have demonstrated the role of live attenuated IAV vector vaccines in preventing and treating H. pylori infection. Our work indicates that vaccination with IAV-NapA induces antigen-specific humoral, cellular, and mucosal immunity, producing a protective and therapeutic effect against H. pylori infection in BALB/c mice. This undescribed H. pylori vaccination approach may provide valuable information for developing vaccines against H. pylori infection.

Vaccine Strategies to Elicit Mucosal Immunity.

Vaccines are essential tools to prevent infection and control transmission of infectious diseases that threaten public health. Most infectious agents enter their hosts across mucosal surfaces, which make up key first lines of host defense against pathogens. Mucosal immune responses play critical roles in host immune defense to provide durable and better recall responses. Substantial attention has been focused on developing effective mucosal vaccines to elicit robust localized and systemic immune responses by administration via mucosal routes. Mucosal vaccines that elicit effective immune responses yield protection superior to parenterally delivered vaccines. Beyond their valuable immunogenicity, mucosal vaccines can be less expensive and easier to administer without a need for injection materials and more highly trained personnel. However, developing effective mucosal vaccines faces many challenges, and much effort has been directed at their development. In this article, we review the history of mucosal vaccine development and present an overview of mucosal compartment biology and the roles that mucosal immunity plays in defending against infection, knowledge that has helped inform mucosal vaccine development. We explore new progress in mucosal vaccine design and optimization and novel approaches created to improve the efficacy and safety of mucosal vaccines.

Recombinant parainfluenza virus 5 expressing clade 2.3.4.4b H5 hemagglutinin protein confers broad protection against H5Ny influenza viruses.

The global circulation of clade 2.3.4.4b H5Ny highly pathogenic avian influenza viruses (HPAIVs) in poultry and wild birds, increasing mammal infections, continues to pose a public health threat and may even form a pandemic. An efficacious vaccine against H5Ny HPAIVs is crucial for emergency use and pandemic preparedness. In this study, we developed a parainfluenza virus 5 (PIV5)-based vaccine candidate expressing hemagglutinin (HA) protein of clade 2.3.4.4b H5 HPAIV, termed rPIV5-H5, and evaluated its safety and efficacy in mice and ferrets. Our results demonstrated that intranasal immunization with a single dose of rPIV5-H5 could stimulate H5-specific antibody responses, moreover, a prime-boost regimen using rPIV5-H5 stimulated robust humoral, cellular, and mucosal immune responses in mice. Challenge study showed that rPIV5-H5 prime-boost regimen provided sterile immunity against lethal clade 2.3.4.4b H5N1 virus infection in mice and ferrets. Notably, rPIV5-H5 prime-boost regimen provided protection in mice against challenge with lethal doses of heterologous clades 2.2, 2.3.2, and 2.3.4 H5N1, and clade 2.3.4.4h H5N6 viruses. These results revealed that rPIV5-H5 can elicit protective immunity against a diverse clade of highly pathogenic H5Ny virus infection in mammals, highlighting the potential of rPIV5-H5 as a pan-H5 influenza vaccine candidate for emergency use.IMPORTANCEClade 2.3.4.4b H5Ny highly pathogenic avian influenza viruses (HPAIVs) have been widely circulating in wild birds and domestic poultry all over the world, leading to infections in mammals, including humans. Here, we developed a recombinant PIV5-vectored vaccine candidate expressing the HA protein of clade 2.3.4.4b H5 virus. Intranasal immunization with rPIV5-H5 in mice induced airway mucosal IgA responses, high levels of antibodies, and robust T-cell responses. Importantly, rPIV5-H5 conferred complete protection in mice and ferrets against clade 2.3.4.4b H5N1 virus challenge, the protective immunity was extended against heterologous H5Ny viruses. Taken together, our data demonstrate that rPIV5-H5 is a promising vaccine candidate against diverse H5Ny influenza viruses in mammals.

An intranasal live-attenuated SARS-CoV-2 vaccine limits virus transmission

The development of effective SARS-CoV-2 vaccines has been essential to control COVID-19, but significant challenges remain. One problem is intramuscular administration, which does not induce robust mucosal immune responses in the upper airways—the primary site of infection and virus shedding. Here we compare the efficacy of a mucosal, replication-competent yet fully attenuated virus vaccine, sCPD9-ΔFCS, and the monovalent mRNA vaccine BNT162b2 in preventing transmission of SARS-CoV-2 variants B.1 and Omicron BA.5 in two scenarios. Firstly, we assessed the protective efficacy of the vaccines by exposing vaccinated male Syrian hamsters to infected counterparts. Secondly, we evaluated transmission of the challenge virus from vaccinated and subsequently challenged male hamsters to naïve contacts. Our findings demonstrate that the live-attenuated vaccine (LAV) sCPD9-ΔFCS significantly outperformed the mRNA vaccine in preventing virus transmission in both scenarios. Our results provide evidence for the advantages of locally administered LAVs over intramuscularly administered mRNA vaccines in preventing infection and reducing virus transmission.

SARS-CoV-2 spike-FLIPr fusion protein plus lipidated FLIPr protects against various SARS-CoV-2 variants in hamsters.

Vaccine-induced mucosal immunity and broad protective capacity against various severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants remain inadequate. Formyl peptide receptor-like 1 inhibitory protein (FLIPr), produced by Staphylococcus aureus, can bind to various Fcγ receptor subclasses. Recombinant lipidated FLIPr (rLF) was previously found to be an effective adjuvant. In this study, we developed a vaccine candidate, the recombinant Delta SARS-CoV-2 spike (rDS)-FLIPr fusion protein (rDS-F), which employs the property of FLIPr binding to various Fcγ receptors. Our study shows that rDS-F plus rLF promotes rDS capture by dendritic cells. Intranasal vaccination of mice with rDS-F plus rLF increases persistent systemic and mucosal antibody responses and CD4/CD8 T-cell responses. Importantly, antibodies induced by rDS-F plus rLF vaccination neutralize Delta, Wuhan, Alpha, Beta, and Omicron strains. Additionally, rDS-F plus rLF provides protective effects against various SARS-CoV-2 variants in hamsters by reducing inflammation and viral loads in the lung. Therefore, rDS-F plus rLF is a potential vaccine candidate to induce broad protective responses against various SARS-CoV-2 variants.IMPORTANCEMucosal immunity is vital for combating pathogens, especially in the context of respiratory diseases like COVID-19. Despite this, most approved vaccines are administered via injection, providing systemic but limited mucosal protection. Developing vaccines that stimulate both mucosal and systemic immunity to address future coronavirus mutations is a growing trend. However, eliciting strong mucosal immune responses without adjuvants remains a challenge. In our study, we have demonstrated that using a recombinant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike-formyl peptide receptor-like 1 inhibitory protein (FLIPr) fusion protein as an antigen, in combination with recombinant lipidated FLIPr as an effective adjuvant, induced simultaneous systemic and mucosal immune responses through intranasal immunization in mice and hamster models. This approach offered protection against various SARS-CoV-2 strains, making it a promising vaccine candidate for broad protection. This finding is pivotal for future broad-spectrum vaccine development.

Gut bacteriome in inflammatory bowel disease: An update on recent advances.

Inflammatory bowel diseases (IBD) are chronic inflammatory gut disorders, majorly classified as ulcerative colitis and Crohn's disease. The complex, multifactorial etiopathogenesis of IBD involves genetic predisposition, environmental cues, aberrant mucosal immune response and a disturbed gut microbiota. Epidemiological trends, studies in gnotobiotic mice models and genome-wide association studies, identifying genes involved in microbial handling, together mount evidence in support of the gut microbiota playing a pivotal role in IBD pathogenesis. Both Crohn's disease and ulcerative colitis are characterized by severe dysbiosis of the gut microbiome, marked by an expansion of detrimental taxa and concomitant depletion of beneficial members. IBD is characterized by reduction in abundances of bacterial genera involved in production of short-chain fatty acids, bio-transformations of bile acids and synthesis of indole-based tryptophan compounds such as Faecalibacterium, Ruminococcus, Coprococcus, Dorea, Parabacteroides, Eubacterium, Oscillibacter and Prevotella and elevation in members of phyla Proteobacteria and Actinobacteria. This imbalance not only results in exaggerated immune signaling towards the microbial antigens, but also results in an altered metabolomic milieu that triggers additional inflammatory cascades. The present review provides insights into the bacterial dysbiosis observed across different intestinal sites and their metabolomic imprints participating in IBD.

Biogenic Selenium Nanoparticles Synthesized by L. brevis 23017 Enhance Aluminum Adjuvanticity and Make Up for its Disadvantage in Mice.

The most popular vaccine adjuvants are aluminum ones, which have significantly reduced the incidence and mortality of many diseases. However, aluminum-adjuvanted vaccines are constrained by their limited capacity to elicit cellular and mucosal immune responses, thus constraining their broader utilization. Biogenic selenium nanoparticles are a low-cost, environmentally friendly, low-toxicity, and highly bioactive form of selenium supplementation. Here, we purified selenium nanoparticles synthesized by Levilactobacillus brevis 23017 (L-SeNP) and characterized them using Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results indicate that the L-SeNP has a particle size ranging from 30 to 200 nm and is coated with proteins and polysaccharides. Subsequently, we assessed the immune-enhancing properties of L-SeNP in combination with an adjuvant-inactivated Clostridium perfringens type A vaccine using a mouse model. The findings demonstrate that L-SeNP can elevate the IgG and SIgA titers in immunized mice and modulate the Th1/Th2 immune response, thereby enhancing the protective effect of aluminum-adjuvanted vaccines. Furthermore, we observed that L-SeNP increases selenoprotein expression and regulates oxidative stress in immunized mice, which may be how L-SeNP regulates immunity.In conclusion, L-SeNP has the potential to augment the immune response of aluminum adjuvant vaccines and compensate for their limitations in eliciting Th1 and mucosal immune responses.

Mucosal immune responses and protective efficacy elicited by oral administration AMP-ZnONPs-adjuvanted inactivated H9N2 virus in chickens

The avian influenza virus is infected through the mucosal route, thus mucosal barrier defense is very important. While the inactivated H9N2 vaccine cannot achieve sufficient mucosal immunity, adjuvants are needed to induce mucosal and systemic immunity to prevent poultry from H9N2 influenza virus infection. Our previous study found that polysaccharide from Atractylodes macrocephala Koidz binding with zinc oxide nanoparticles (AMP-ZnONPs) had immune-enhancing effects in vitro. This study aimed to evaluate the mucosal immune responses of oral whole-inactivated H9N2 virus (WIV)+AMP-ZnONPs and its impact on the animal challenge protection, and the corresponding changes of pulmonary metabolomics after the second immunization. The results showed that compared to the WIV, the combined treatment of WIV and AMP-ZnONPs significantly enhanced the HI titer, IgG and specific sIgA levels, the number of goblet cells and intestinal epithelial lymphocytes (iIELs) as well as the expression of J-chain, polymeric immunoglobulin receptor (pIgR), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β). In viral attack experiments, WIV combing with AMP-ZnONPs effectively reduced lung damage and viral titers in throat swabs. Interestingly, significant changes of both the IgA intestinal immune network and PPAR pathway could also be found in the WIV+AMP-ZnONPs group compared to the non-infected group. Taken together, these findings suggest that AMP-ZnONPs can serve as a potential mucosal vaccine adjuvant, thereby avoiding adverse stress and corresponding costs caused by vaccine injection.

Mucosal Immunity against SARS-CoV-2 in the Respiratory Tract.

The respiratory tract, the first-line defense, is constantly exposed to inhaled allergens, pollutants, and pathogens such as respiratory viruses. Emerging evidence has demonstrated that the coordination of innate and adaptive immune responses in the respiratory tract plays a crucial role in the protection against invading respiratory pathogens. Therefore, a better understanding of mucosal immunity in the airways is critical for the development of novel therapeutics and next-generation vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other respiratory viruses. Since the coronavirus disease 2019 pandemic, our knowledge of mucosal immune responses in the airways has expanded. In this review, we describe the latest knowledge regarding the key components of the mucosal immune system in the respiratory tract. In addition, we summarize the host immune responses in the upper and lower airways following SARS-CoV-2 infection and vaccination, and discuss the impact of allergic airway inflammation on mucosal immune responses against SARS-CoV-2.

Cross-protective HCoV immunity reduces symptom development during SARS-CoV-2 infection.

Numerous clinical parameters link to severe coronavirus disease 2019, but factors that prevent symptomatic disease remain unknown. We investigated the impact of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and endemic human coronavirus (HCoV) antibody responses on symptoms in a longitudinal children cohort (n = 2,917) and a cross-sectional cohort including children and adults (n = 882), all first exposed to SARS-CoV-2 (March 2020 to March 2021) in Switzerland. Saliva (n = 4,993) and plasma (n = 7,486) antibody reactivity to the four HCoVs (subunit S1 [S1]) and SARS-CoV-2 (S1, receptor binding domain, subunit S2 [S2], nucleocapsid protein) was determined along with neutralizing activity against SARS-CoV-2 Wuhan, Alpha, Delta, and Omicron (BA.2) in a subset of individuals. Inferred recent SARS-CoV-2 infection was associated with a strong correlation between mucosal and systemic SARS-CoV-2 anti-spike responses. Individuals with pre-existing HCoV-S1 reactivity exhibited significantly higher antibody responses to SARS-CoV-2 in both plasma (IgG regression coefficients = 0.20, 95% CI = [0.09, 0.32], P < 0.001) and saliva (IgG regression coefficient = 0.60, 95% CI = [0.088, 1.11], P = 0.025). Saliva neutralization activity was modest but surprisingly broad, retaining activity against Wuhan (median NT50 = 32.0, 1Q-3Q = [16.4, 50.2]), Alpha (median NT50 = 34.9, 1Q-3Q = [26.0, 46.6]), and Delta (median NT50 = 28.0, 1Q-3Q = [19.9, 41.7]). In line with a rapid mucosal defense triggered by cross-reactive HCoV immunity, asymptomatic individuals presented with higher pre-existing HCoV-S1 activity in plasma (IgG HKU1, odds ratio [OR] = 0.53, 95% CI = [0.29,0.97], P = 0.038) and saliva (total HCoV, OR = 0.55, 95% CI = [0.33, 0.91], P = 0.019) and higher SARS-CoV-2 reactivity in saliva (IgG S2 fold change = 1.26, 95% CI = [1.03, 1.54], P = 0.030). By investigating the systemic and mucosal immune responses to SARS-CoV-2 and HCoVs in a population without prior exposure to SARS-CoV-2 or vaccination, we identified specific antibody reactivities associated with lack of symptom development.IMPORTANCEKnowledge of the interplay between human coronavirus (HCoV) immunity and severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection is critical to understanding the coexistence of current endemic coronaviruses and to building knowledge potential future zoonotic coronavirus transmissions. This study, which retrospectively analyzed a large cohort of individuals first exposed to SARS-CoV-2 in Switzerland in 2020-2021, revealed several key findings. Pre-existing HCoV immunity, particularly mucosal antibody responses, played a significant role in improving SARS-CoV-2 immune response upon infection and reducing symptoms development. Mucosal neutralizing activity against SARS-CoV-2, although low in magnitude, retained activity against SARS-CoV-2 variants underlining the importance of maintaining local mucosal immunity to SARS-CoV-2. While the cross-protective effect of HCoV immunity was not sufficient to block infection by SARS-CoV-2, the present study revealed a remarkable impact on limiting symptomatic disease. These findings support the feasibility of generating pan-protective coronavirus vaccines by inducing potent mucosal immune responses.

Edible Vaccines: A Patent-Driven Exploration of Immunization Technologies.

Vaccines are biological preparations that improve immunity to particular diseases. Particularly for poor developing nations, edible vaccines show significant potential as a financially advantageous, simple to administer, straightforward to store, fail-safe, and socially and culturally acceptable vaccine delivery system. A vaccine incorporates the gene-encoding bacterial or viral disease-causing agent in plants without losing its immunogenic property. Potatoes, tomatoes, rice, soybeans, and bananas are the primary plants for edible vaccines. It activates the systemic and mucosal immunity responses against a foreign disease-causing organism. It offers exciting possibilities to reduce diseases like hepatitis B, rabies, HIV/AIDS (human immunodeficiency virus infection and acquired immune deficiency syndrome), etc. These vaccines provide many benefits, like being convenient to administer, efficiently storing, and readily acceptable drug delivery systems for patients of different age groups. So, an edible vaccine may be the most convenient vaccine to improve immunity. However, there are a lot of technical and regulatory challenges to overcome in the way of edible vaccine technology. Though all seem surmountable, various technical obstacles and regulatory and non-scientific challenges need to be overcome. Moreover, edible vaccine patents represent a cutting-edge area of biotechnology, where the integration of genetic material into edible substances holds great promise for revolutionizing vaccination methods. These patents aim to harness the potential of plants and other edibles to stimulate immune responses, offering a potential alternative to traditional injectable vaccines. This review states the technologies, host plants, current status, recent patents, the future of this new preventive modality, and different regulatory issues concerning edible vaccines.

Mucosal Genes Encoding Clock, Inflammation and Their Mutual Regulators Are Disrupted in Pediatric Patients with Active Ulcerative Colitis.

Patients with active ulcerative colitis (UC) display a misalignment of the circadian clock, which plays a vital role in various immune functions. Our aim was to characterize the expression of clock and inflammation genes, and their mutual regulatory genes in treatment-naïve pediatric patients with UC. Using the Inflammatory Bowel Disease Transcriptome and Metatranscriptome Meta-Analysis (IBD TaMMA) platform and R algorithms, we analyzed rectal biopsy transcriptomic data from two cohorts (206 patients with UC vs. 20 healthy controls from the GSE-109142 study, and 43 patients with UC vs. 55 healthy controls from the GSE-117993 study). We compared gene expression levels and correlation of clock genes (BMAL1, CLOCK, PER1, PER2, CRY1, CRY2), inflammatory genes (IκB, IL10, NFκB1, NFκB2, IL6, TNFα) and their mutual regulatory genes (RORα, RORγ, REV-ERBα, PGC1α, PPARα, PPARγ, AMPK, SIRT1) in patients with active UC and healthy controls. The clock genes BMAL1, CLOCK, PER1 and CRY1 and the inflammatory genes IκB, IL10, NFκB1, NFκB2, IL6 and TNFα were significantly upregulated in patients with active UC. The genes encoding the mutual regulators RORα, RORγ, PGC1α, PPARα and PPARγ were significantly downregulated in patients with UC. A uniform pattern of gene expression was found in healthy controls compared to the highly variable expression pattern in patients with UC. Among the healthy controls, inflammatory genes were positively correlated with clock genes and they all showed reduced expression. The difference in gene expression levels was associated with disease severity and endoscopic score but not with histological score. In patients with active UC, clock gene disruption is associated with abnormal mucosal immune response. Disrupted expression of genes encoding clock, inflammation and their mutual regulators together may play a role in active UC.

Comparison of Omicron breakthrough infection versus monovalent SARS-CoV-2 intramuscular booster reveals differences in mucosal and systemic humoral immunity

Our understanding of the quality of cellular and humoral immunity conferred by coronavirus disease 2019 (COVID-19) vaccination alone versus vaccination plus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) breakthrough (BT) infection remains incomplete. While the current (2023) SARS-CoV-2 immune landscape of Canadians is complex, in late 2021 most Canadians had either just received a third dose of COVID-19 vaccine, or had received their two dose primary series and then experienced an Omicron BT. Herein we took advantage of this coincident timing to contrast cellular and humoral immunity conferred by three doses of vaccine versus two doses plus BT. Our results show that mild BT infection induces cell-mediated immune responses to variants comparable to an intramuscular vaccine booster dose. In contrast, BT subjects had higher salivary IgG and IgA levels against the Omicron spike and enhanced reactivity to the ancestral spike for the IgA isotype, which also reacted with SARS-CoV-1. Serum neutralizing antibody levels against the ancestral strain and the variants were also higher after BT infection. Our results support the need for vaccines that emulate the enhanced mucosal and humoral immunity induced by Omicron BT without exposing individuals to the risks associated with SARS-CoV-2 infection.One Sentence SummaryOmicron breakthrough elicits cross-reactive systemic and mucosal immune responses in vaccinated adults.

P131 Therapeutic effects of KPG-818 in a trinitrobenzene sulfonic acid - induced mouse Crohn's/Ulcerative Colitis model

Abstract Background Immunomodulatory drugs have the potential therapeutic benefit not only in malignancy but also in diseases characterized by an inflammatory phenotype. In inflammatory bowel diseases (IBD), colonic inflammation results from dysregulation of the mucosal immune responses to intestinal flora together with genetic and environmental factors. Inflammatory cytokines are implicated in pathogenesis of IBD. Treatments for IBD that improve clinical outcomes and limit adverse effects are needed. KPG-818 is a novel generation of lenalidomide derivative and small molecule immunomodulatory drug. KPG-818 is currently under clinical development for therapy of multiple myeloma, lymphoma (phase 1), and systemic lupus erythematosus (SLE) (phase 2a). Remarkable immunomodulatory effects of KPG-818 are observed in SLE patients. In preclinical studies, KPG-818 significantly inhibits inflammatory cytokines interleukin-6 and TNF-α in human peripheral blood mononuclear cells, inhibits tumor growth in multiple myeloma and lymphoma xenograft tumor models. Here we report the significant therapeutic effects of KPG-818 in a chronic Crohn’s/ulcerative colitis mouse model. Methods Trinitrobenzene Sulfonic Acid (TNBS) was intra-colonially administered to induce Balb/c mouse Crohn’s/ulcerative colitis model at 50 mg/kg, once a week for 4 weeks. KPG-818 was orally administered at doses of 0.03, 0.12, 0.4, and 1.0 mg/kg, once a day for 6 consecutive weeks. Upadacitinib served as a positive control drug. Vehicle solution served as a negative control. To evaluate the therapeutic effects of the KPG-818, disease activity index (DAI) of ulcerative colitis, the degree of weight loss, fecal morphology, and rectal bleeding were scored once every other day for six consecutive weeks. At the end of the study, colonic samples were collected for gross observation and scoring of macroscopic damage, measurement of length and weight, and histopathological diagnosis and scoring. At the end of study, peripheral blood samples were also collected for analyses of immune cells and cytokines. Results Compared to the vehicle control, KPG-818 significantly improved the body weight loss, disease activity of ulcerative colitis, gross degree of colorectal injury, pathological lesions of colorectal tissue, inhibited the inflammatory cytokines in a dose-response manner. The effective dose was as low as 0.03 mg/kg. KPG-818 showed similar therapeutic effects to Upadacitinib. Conclusion In this mouse model of chronic Crohn’s/ulcerative colitis, KPG-818 showed remarkable therapeutic effects in a dose-dependent manner. These data encourage the clinical evaluation of KPG-818 in inflammatory bowel diseases.

ECCO Global Grant Genetic risk factors for IBD in its emergent phase in sub-Saharan Africa

Abstract Background and Aims Inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), is an idiopathic, chronic, and frequently disabling inflammatory disorder of the intestines characterized by a dysregulated mucosal immune response. The pathophysiology of the disease remains incompletely understood. Genetic factors affecting disease are under investigation, however, genetic studies in non-European populations are scarce and it is an urgent scientific, social, and ethical requirement that research in under-studied populations is prioritized. The objective of this study is to understand the genetics of IBD in sub-Saharan African ancestry populations and to identify genetic factors that affect pathogenesis of IBD in this region. Methodology A case-control study will be conducted from January 2024 to December 2025. Consecutive eligible subjects with IBD and controls will be invited to take part in the study. Data will be collected through chart review, structured interviews, and collection of saliva samples for genotyping using the H3Africa chip in the first instance. Genome-wide imputation and replication analysis will be done. Single-marker association analyses will be performed using the Cochran Armitage trend and logistic regression test after correction for population structure. We will look at known European ancestry and African American (AA) IBD-associated variants as well as variants that are unique to our populations (we will be able to look at local admixture in the AA population to see if these variants are replicated). Anticipated Impact This study will contribute significantly to knowledge of genetic risk factors for IBD in sub-Saharan Africa. It may also help to identify potential complications of treatments such as thiopurines which have been commonly used in European populations but where experience of use in sub-Saharan Africa is lacking.

The effect of bromhexine on mucosal immune response against avian coronavirus infectious bronchitis vaccine in chickens

Avian coronavirus infectious bronchitis (IB) is one of the most important and contagious disease in chickens, all over the world. Using of chemical compounds that improve the mucosal immune response to IB vaccine can increase resistance against the virus. To examine the effect of Bromhexine on the mucosal immune response against IB vaccine, 360 one-day broiler chicks were allocated to eight groups, randomly. Group one was the control group with no vaccine so that the group only used Bromhexine. Groups 2, 3, and 4 received IB vaccine for once, twice, and three times at the age of 5, 15, and 25 days, respectively. These groups received Bromhexine from 48 hrs before the vaccination to 24 hrs after receiving the vaccine in drinking water. Group five was the negative control group and did not receive Bromhexine and IB vaccine. Sampling in group five was at the age of 15 days. Groups six, seven, and eight were the main treatment control groups and received IB vaccine at the age of 5, 15, and 25 days without Bromhexine. The chickens were slaughtered 10 days after the vaccination and nose and trachea samples were collected and the mucus surface of respiratory was rinsed. Afterwards, specific immunoglobin A (IgA) level against IB vaccine in the respiratory mucus was measured through ELISA using chicken IgA specific antiglobulin. The results showed that the use of Bromhexine on the first vaccination had no effect on mucosal immune response. However, with the second and third vaccinations, antibody titter to IB vaccine was higher than chickens received vaccine without Bromhexin. It appears that using Bromhexine in booster IB vaccination can improve specific mucosal immune response.

Systemic and mucosal immune responses in red tilapia (Oreochromis sp.) following immersion vaccination with a chitosan polymer-based nanovaccine against Aeromonas veronii

A mucoadhesive chitosan polymer-based nanoplatform has been increasingly recognized as an effective mucosal vaccine delivery system for fish. The present study aimed to investigate the effectiveness of immersion vaccination with a chitosan polymer-based nanovaccine to elicit an immune response in serum and mucus of red tilapia and evaluate its protective efficacy after immersion challenge with a heterogenous strain of Aeromonas veronii UDRT09. Six hundred red tilapia (22 ± 1.8 g) were randomly allocated into four experimental groups: control, empty-polymeric nanoparticle (PC), formalin-killed vaccine (FKV), and chitosan polymer-based nanovaccine (CS-NV) in triplicate. The specific IgM antibody levels and their bactericidal activity were assessed in serum and mucus for 28 days after immersion vaccination and followed by immersion challenge with A. veronii. The immersion vaccine was found to be safe for red tilapia, with no mortalities occurring during the vaccination procedure. The specific IgM antibody levels and bactericidal activity against A. veronii in both serum and mucus were significantly higher in red tilapia vaccinated with CS-NV compared to the FKV and control groups at all time points. Furthermore, the serum lysozyme activity, ACH50, and total Ig levels demonstrated a significant elevation in the groups vaccinated with CS-NV compared to the FKV and control groups. Importantly, the Relative Percentage Survival (RPS) value of the CS-NV group (71 %) was significantly higher than that of the FKV (15.12 %) and PC (2.33 %) groups, respectively. This indicates that the chitosan polymer-based nanovaccine platform is an effective delivery system for the immersion vaccination of tilapia.

Enhancing humoral and mucosal immune response of PED vaccine candidate by fusing S1 protein to nanoparticle multimerization

Porcine epidemic diarrhea virus (PEDV) is a highly infectious pathogen with a high mortality rate, which poses a serious threat to newborn piglets. A rapid, safe and effective vaccine is necessary for protecting pigs from PED infection. Nanoparticles have become molecular scaffolds for displaying soluble antigens due to their unique physical and chemical properties. Here, a vaccine candidate was based on the display of PEDV S1 protein on a mi3 nanoparticle platform using SpyTag/SpyCatcher technology. The size, zeta potential and microstructure of the S1-mi3 NPs were investigated, and their effects on the uptake of antigen-presenting cells (APCs) and maturation of dendritic cells (DCs) were analyzed. Mice were immunized via muscular and intranasal administrations, and the levels of humoral, cellular and mucosal immune responses were analyzed. As a result, S1 proteins were surface-displayed on NPs successfully, which self-assembled into nanoparticles composed of 60 subunits and showed superior safety and stability. In addition, mi3 NPs promoted antigen internalization and dendritic cell (DCs) maturation. In the mouse model, S1-mi3 NPs significantly increased the PEDV-specific antibody including serum IgG, secretory IgA (SIgA) and neutralizing antibodies (NAb). Furthermore, S1-mi3 NPs elicited more CD3+CD4+ and CD3+CD8+ T cell and cellular immune-related cytokines (IFN-γ and IL-4) compared to monomeric S1. In particular, it can induce an effective germinal center-specific (GC) B cell response, which is closely related to the production of neutralizing antibodies. Overall, S1-mi3 NPs are a promising subunit vaccine candidate against PEDV, and this self-assembly NPs also provide an attractive platform for improving vaccine efficacy against emerging pathogens.

Nucleotides supplementation (Nucleoforce fish™) in Caspian roach (Rutilus caspicus) diet: Growth performance, skin mucosal immune response, and resistance to salinity stress

In this study, the growth, epidermal mucosal immunity, expression of growth-related genes, cross-protection, and resistance to salinity stress of Caspian roach were scrutinized in response to dietary levels of nucleotides (NT). Accordingly, 1200 fish (0.51 ± 0.01 g) were fed ad libitum with a basal diet (38.88 % crude protein and 10.04 % crude lipid in dry basis) containing incremental levels of NT at 0 (NT-0; control), 0.3 g kg−1 (NT-0.3), 0.6 g kg−1 (NT-0.6), and 1.2 g kg−1 (NT-1.2) for 8 weeks in triplicates. The growth performance was significantly increased in the fish fed with NT-0.6 and NT-1.2 diets compared to the control group (p < 0.05). A significant elevation in the growth hormone and insulin-like growth factor-I gene expression was recorded in NT-added groups at 0.6 and 1.2 g kg−1 compared to the control group (p < 0.05). In contrast to the control group, feeding on NT-0.6 and NT-1.2 diets had a remarkable effect on the skin mucus soluble protein and immunoglobulin levels (p < 0.05). After the feeding trial, we examined how salinity stress (15 g/l salinity) lonely and salinity stress under non-lethal thermal shock (+10 °C) affected heat shock protein (HSP70). Then, the mRNA expression of HSP70 gene from the gill was analyzed at 0, 2, 8, and 24 h post-challenge tests. The HSP70 gene expression level was approximately up-regulated more than 2-fold in NT-6 and NT-1.2 treatments compared to the control group under the salinity stress. Altogether, this research represents that the addition of NT at 0.6 and 1.2 g kg−1 in Caspian roach diet can improve overall performance and resistance to salinity stress.

Genomic and vaccine preclinical studies reveal a novel mouse-adapted Helicobacter pylori model for the hpEastAsia genotype in Southeast Asia.

Introduction. Helicobacter pylori infection is a major global health concern, linked to the development of various gastrointestinal diseases, including gastric cancer. To study the pathogenesis of H. pylori and develop effective intervention strategies, appropriate animal pathogen models that closely mimic human infection are essential.Gap statement. This study focuses on the understudied hpEastAsia genotype in Southeast Asia, a region marked by a high H. pylori infection rate. No mouse-adapted model strains has been reported previously. Moreover, it recognizes the urgent requirement for vaccines in developing countries, where overuse of antimicrobials is fuelling the emergence of resistance.Aim. This study aims to establish a novel mouse-adapted H. pylori model specific to the hpEastAsia genotype prevalent in Southeast Asia, focusing on comparative genomic and histopathological analysis of pathogens coupled with vaccine preclinical studies.Methodology. We collected and sequenced the whole genome of clinical strains of H. pylori from infected patients in Vietnam and performed comparative genomic analyses of H. pylori strains in Southeast Asia. In parallel, we conducted preclinical studies to assess the pathogenicity of the mouse-adapted H. pylori strain and the protective effect of a new spore-vectored vaccine candidate on male Mlac:ICR mice and the host immune response in a female C57BL/6 mouse model.Results. Genome sequencing and comparison revealed unique and common genetic signatures, antimicrobial resistance genes and virulence factors in strains HP22 and HP34; and supported clarithromycin-resistant HP34 as a representation of the hpEastAsia genotype in Vietnam and Southeast Asia. HP34-infected mice exhibited gastric inflammation, epithelial erosion and dysplastic changes that closely resembled the pathology observed in human H. pylori infection. Furthermore, comprehensive immunological characterization demonstrated a robust host immune response, including both mucosal and systemic immune responses. Oral vaccination with candidate vaccine formulations elicited a significant reduction in bacterial colonization in the model.Conclusion. Our findings demonstrate the successful development of a novel mouse-adapted H. pylori model for the hpEastAsia genotype in Vietnam and Southeast Asia. Our research highlights the distinctive genotype and pathogenicity of clinical H. pylori strains in the region, laying the foundation for targeted interventions to address this global health burden.