Administration Of Antigen Research Articles

Oral Bacterial Lysate OM-85: Advances in Pharmacology and Therapeutics.

Bacterial lysates are known for having immunomodulatory properties and have been used mainly for the prevention and treatment of respiratory tract infections (RTIs). However, rigorous studies are needed to confirm the clinical efficacy of bacterial lysates with various bacterial antigen components, preparation methods, administration routes and course of treatment. OM-85, an oral standardized lysate prepared by alkaline lysis of 21 strains from 8 species of common respiratory tract pathogens, is indicated as immunotherapy for prevention of recurrent RTIs and acute infectious exacerbations of chronic bronchitis. OM-85 acts on multiple innate and adaptive immune targets and can restore type 1helper T (Th1)/Th2 balance. Sporadic studies have shown advances in pharmacology and therapeutics of OM-85, and thus an update review is necessary. Literature was retrieved by searching PubMed, Web of science, Embase, CNKI, and Full Text Database of Chinese Medical Journals. New roles of OM-85 were discovered in prevention and treatment of lung cancer, pulmonary tuberculosis, SARS-CoV-2 infection, allergic rhinitis, pulmonary fibrosis, atopic dermatitis, and nephrotic syndrome. Pharmacoeconomic values of OM-85 were demonstrated in prophylaxis and treatment of RTIs, chronic obstructive pulmonary disease, asthma, chronic bronchitis, rhinosinusitis and allergic rhinitis. Two consecutive courses of OM-85 (6 or 12 months apart) could prevent recurrent RTIs in children. Maternal OM-85 treatment could offer benefits for offspring. Product-specific response was observed. The efficacy of OM-85 may be associated with patient's characteristics (eg, severity of the disease, age, immune response pattern, malignancy risk stratification). OM-85 can improve effectiveness of standard care for some primary diseases, and carry significant pharmacoeconomic implications. The benefits shown by OM-85 in vitro and in vivo, when extrapolated to humans, are exciting but also require caution. Individualized treatment may need to be considered. It is necessary to compare the efficacy and safety of various bacterial lysate preparations.

Testing Tolerance in Cow Milk Protein Allergy Patients: Milk Ladder or Direct Milk Administration?

Abstract Background Cow’s milk protein allergy (CMPA) is a major health concern; its prevalence is between 1.9% and 4.9% in the first year of life. Tolerance to cow’s milk is tested after at least 6 months of elimination diet through two common approaches which are the milk ladder method and direct milk administration. Aim To compare tolerance frequency between those who had milk products reintroduced via milk ladder to those who were directly exposed to pure milk antigen after 6 months of elimination diet, and to assess the factors affecting the overall tolerance frequency of cow’s milk after 6 months elimination diet. Methods A randomized controlled clinical trial involving 116 children recruited from the Pediatric Gastroenterology Clinic, Children’s Hospital, in Shams University, diagnosed as non-IgE mediated cow’s milk protein allergy proven by elimination re-challenge test and followed six months of elimination diet. The included children were randomly assigned into 2 groups, where one group had milk products reintroduced via 6 steps milk ladder, and the second group had direct milk antigen administration in gradual increments. They were followed up for 2 months after the introduction of milk or milk containing products to confirm resolution of allergy. Results The overall tolerance rate after 6 months elimination diet was 81% with no significant difference between the two approaches (Direct milk 84.5%, and milk ladder 77.6%), in addition, the regression analysis showed that weight was a significant factor influencing the resolution of CMPA patients, with normal weight patients having higher chance of resolution than underweight patients (odds ratio=3.73). Conclusion Non-IgE medicated CMPA has high rate of resolution after 6 months elimination diet. Both approaches of introduction were equivalent.

Oral administration enhances directly mucosal immune system in intestine of olive flounder (Paralichthys olivaceus)

Aquaculture is notably vulnerable to diseases, with Edwardsiella tarda causing significant mortality across various commercially important fish species in both freshwater and marine environments. In the aquaculture industry, sustainable disease control hinges on the effective development of vaccines. Oral vaccines present an appealing approach to immunization in fish due to their ease of antigen administration, reduced stress compared to non-oral delivery methods, and their potential applicability to both small and large finfish species. In mammals, the exposure of mucosal surfaces to antigens results in the secretion of antigen-specific IgA at these locations. Mammals have a common mucosal immune system, in which stimulation of one epithelium can also give rise to specific IgA or IgM responses in other mucosal organs. Mucosal immunoglobulins are particularly important in developing vaccines that provide mucosal immunity. However, it remains unclear whether fish share a common mucosal system. Moreover, neither Peyer's patches nor intestinal lymph nodes were identified. Nevertheless, oral vaccination remains an attractive method for inducing immunity. We investigated whether the activation of the mucosal immune response was induced by direct injection of the antigen. After oral antigen administration, antigen-specific antibody titers increased in the experimental group (E. tarda FKC vaccine). In the challenge experiment, the cumulative survival rate was 72% (E. tarda). This suggests that oral administration of antigens can activate intestinal mucosal immunity in flounders. Additionally, these results help understand the intestinal mucosal immune system of teleost fish. In the future, research on the signaling mechanisms of these genes is expected to provide helpful information for developing vaccine adjuvants.

TLR agonists promote formation of Tertiary Lymphoid Structure and improve anti-glioma immunity.

Glioma, characterized by limited lymphocytic infiltration, constitutes an "immune-desert" tumor displaying insensitivity to various immunotherapies. This study aims to explore therapeutic strategies for inducing tertiary lymphoid structure (TLS) formation within the glioma microenvironment (GME) to transition it from an immune-resistant to an activated state. TLS formation in GME was successfully induced by intracranial administration of Toll-like receptor (TLR) agonists (OK-432, TLR2/4/9 agonist) and glioma antigens (i.c. αTLR-mix). We employed staining analysis, antibody neutralization, single-cell RNA sequencing (scRNA-Seq), and BCR/TCR sequencing to investigate the underlying mechanisms of TLS formation and its role in anti-glioma immunity. Additionally, a preliminary translational clinical study was conducted. TLS formation correlated with increased lymphocyte infiltration in GME and led to improved prognosis in glioma-bearing mice. In the study of TLS induction mechanisms, certain macrophages/microglia and Th17 displayed markers of "LTo" and "LTi" cells, respectively, interaction through LTα/β-LTβR promoted TLS induction. Post-TLS formation, CD4+ and CD8+ T cells but not CD19+ B cells contributed to anti-glioma immunity. Comparative analysis of B/T cells between brain and lymph node showed that brain B/T cells unveiled switch from naïve to mature, some B cells highlighted an enrichment of CSR-associated genes, V gene usage and clonotype bias were observed. In related clinical studies, i.c. αTLR-mix treatment exhibited tolerability, and chemokines/cytokines assay provided preliminary evidence supporting TLS formation in GME. TLS induction in GME enhanced anti-glioma immunity, improved the immune microenvironment, and controlled glioma growth, suggesting potential therapeutic avenues for treating glioma in the future.

The role of big data analysis for resources optimization of immunization programmes in Pakistan.

Madam, The significance of Big Data Analysis (BDA) in optimizing immunization programmes in Pakistan emerges within the context of global and regional immunization challenges post the COVID-19 pandemic. Despite recovery efforts, a substantial number of children globally remain under-vaccinated, with 14.3 million zero-dose children in 2022.[1] South Asia, primarily India, has shown notable progress, exceeding pre-pandemic coverage levels.[2] In Pakistan, the Expanded Programme on Immunization (EPI) launched in 1978 aims to combat high under-five mortality rates due to vaccine-preventable diseases.[3] However, vaccine coverage remains suboptimal, with only 66% of children aged 12-23 months receiving basic EPI vaccines.[3] This is compounded by reduced doses administered later in schedules, influenced by limited access, awareness gaps, and insufficient vaccinators, especially in rural areas. [3] Big data analytics can help tackle challenges, improve resource allocation, and optimize immunization in Pakistan. The vital role of BDA in optimizing Pakistan's immunization programmes is rooted in its manifold health benefits. BDA aids disease prevention, identifies health risk factors, and enhances healthcare strategies.[4] Amid health emergencies like COVID-19, BDA leverages information technology to fortify health systems, enhancing decision-making, reducing errors, and conserving resources.[4] BDA's dynamic potential is evident. Its predictive tools swiftly pinpoint high-risk patients, streamlining care and elevating healthcare outcomes.[4] BDA draws insights from vast datasets for informed decisions. A recent study conducted in Sindh, increased vaccinator attendance from 44% to 88%, by factoring in results of BDA of Electronic Immunization Registries into their decision making.[5] BDA of antigen administration during accelerated outreach efforts revealed substantial boosts, compared to routine activities.[5] These findings spurred continued efforts in high-risk areas, showcasing BDA's impact in project acceleration and resource optimization.[5] This case highlights BDA's transformative role, enhancing immunization programs through data-driven insights. To harness the potential of BDA in immunization, Pakistan's healthcare system requires a digital overhaul. This entails prioritizing active patient data collection, storage, and analysis on a national scale. Collected data would facilitate targeted vaccination efforts in vulnerable areas. Storing data supports future research and predictive analysis, offering insights into current measures' efficacy and enabling necessary adjustments. A robust data analysis infrastructure, coupled with healthcare professional training, is essential. Cost-effective data security is vital. Digital registries in tertiary care hospitals and rural centres can aid government analysis. This holistic approach seeks to establish a digital healthcare ecosystem, involve the public, and implement data-driven solutions for improved immunization and overall public health in Pakistan.

Inhibition of TLR4 and NLRP3 leads to the exacerbation of IgE specific antibodies in mouse allergic models based on subcutaneous or intranasal immunization respectively

A significant increase in the prevalence of diseases linked with IgE production can be seen in recent years, but the question about the role of TLR receptors in this process remains controversial. According to the hygiene hypothesis, the decrease of the contact of the individual with pathogens that contain PRR receptor ligands in the recent years leads to the development of allergic diseases. The aim of this work was to investigate whether TLR4 and NLRP3 receptor activation contributes to allergen-specific antibody formation. BALB/c mice were immunized according to two different protocols. In the first one, OVA antigen was administered in 0.1 µg dose 2-3 times a week for 6 weeks by subcutaneous route. In the second one, OVA was administered in 0.3 µg dose intranasally in combination with 4 ng of benzo(a)pyrene (BaP) 2 times a week for 8 weeks. In both cases, TLR4 and NLRP3 receptor inhibitors, namely TLR4-IN-C34 in 1 mg/kg dose and CY- 09 in 20 mg/kg dose respectively were also administered to the some of the mice. Specific antibody production was determined by ELISA. Immunization of mice with TLR4-IN-C34 significantly (p 0.01) amplify IgE production (about 2.5 times in comparison with control group), but has no effect on specific IgG1 production in subcutaneous model. Specific IgE titers in the control group immunized without small molecule inhibitor and in the TLR4-IN-C34 group were (3±0.6) × 103 and (8±2) × 103, respectively. In this model, CY-09 administration has no effect on humoral immune response. In the secondary (intranasal) model, BaP significantly increase specific IgE and IgG1 production. CY-09 but not TLR4-IN-C34 administered in combination with BaP significant (p 0.05) and approximately 2 times enhances specific IgE but not IgG1 production. Specific IgE titers in the control group without inhibitor and in the CY-09 group were (2.0±0.4) × 102 and (5.1±0.3) × 102, respectively. So, PRR-activation, in our case activation of TLR4 in the model based on subcutaneous immunization or NLRP3 in the model based on intranasal antigen administration with BaP suppressed the production of allergen-specific IgE, but not IgG1. These data are in consistent with the hygiene theory of allergy development.

Immune response, oxidative stress, and histological changes of Wistar rats after being administered with Parascaris equorum antigen

Worldwide, particularly in developing nations, helminth infections are the leading causes of livestock illness and mortality. Parascaris (P.) equorum, a parasitic worm from the Ascarididae family, significantly impacts the production, health, and working performance of equines. This study aimed to investigate the impact of intraperitoneal sensitization of P. equorum on the immune system, oxidative stress, and histology in Wistar rats. After acclimatization for 7 days, we divided the rats into five groups, each consisting of six rats. Group I, serving as the control, was administered distilled water, followed by groups II (day 7), III (day 14), IV (day 21), and V (day 33). The rats were euthanized every day mentioned (Days 7–33). On day 0, a dosage of 1ml/100 gm rat (containing 500 μg/ml protein content) emulsified crude antigen extract with an incomplete Freund’s adjuvant (1:1 volume), followed by a second dose of the same antigen concentration on day 7. To assess the allergenicity of this nematode, we measured a whole blood profile, serum levels of IFN-γ, IL-5, IL-10, IL-13, and IL-33, total immunoglobulins IgE and IgG, and oxidative stress markers. Also, we examined histological changes in the liver, kidney, and spleen. The results showed that values of total leukocyte count, granulocytes, monocytes, and lymphocytes were significantly (P < 0.05) increased on day 14 post-infection relative to other days of investigation. It was found that the levels of total immunoglobulins (IgE and IgG) and cytokines (INF-γ, IL-5, IL-13, and IL-33) on days 14 and 21 were significantly higher than in the control group. At all periods of the experiment, the injected group exhibited significantly higher concentrations of MDA and NO compared to the control group (P < 0.05). Conversely, GSH and CAT levels (P < 0.05) dropped significantly on days 7, 14, and 21. Different rat tissues showed alterations. Ultimately, this study described the detrimental effects of P. equorum crude antigen administration on the immune system, oxidative states, and histological changes of Wistar rats at various intervals.

Aspiration of acidified milk induces milk allergy by activating alveolar macrophages in mice

BackgroundEpidemiological studies have identified associations between gastroesophageal reflux (GER) and cow's milk allergy (CMA) in infants. However, the role of GER in the development of CMA remains poorly understood. Our primary objectives were to develop a mouse model that suggests GER as a potential pathogenic mechanism for CMA and to elucidate the immunological mechanisms that connect lung innate immunity with CMA. MethodsMice were exposed to cow's milk (CM) treated with hydrochloric acid through repeated aspiration into their airways. Subsequently, they were challenged by intraperitoneal injection of CM extract. The immunological mechanisms were investigated using comprehensive single-cell RNA sequencing (scRNA-seq) analysis of the lungs, combined with the use of genetically modified mice. ResultsMice exposed to CM mixed with hydrochloric acid via airway sensitization developed CMA, as evidenced by the production of antigen-specific IgE and IgG antibodies, and the induction of anaphylaxis upon systemic antigen administration. In contrast, aspiration of CM alone did not induce CMA. scRNA-seq analysis revealed potential roles of alveolar macrophages in response to hydrochloric acid. Mice lacking the TLR4 pathway were protected from developing CMA. ConclusionsWe have developed a novel mouse model for CMA that utilizes the natural antigen and follows the physiological airway sensitization pathway, thus potentially resembling clinical scenarios. This model, named the acidified milk aspiration-induced allergy model, has the potential to shed light on the role of early innate immunity by analyzing a more physiological model.

Relationship between protein conformational stability and its immunogenicity when administering antigens to mice using adjuvants-Analysis employed the CH2 domain in human antibodies.

Antigen-presenting cells (APCs) play a crucial role in the immune system by breaking down antigens into peptide fragments that subsequently bind to major histocompatibility complex (MHC) molecules. Previous studies indicate that stable proteins can impede CD4+ T cell stimulation by hindering antigen processing and presentation. Conversely, certain proteins require stabilization in order to activate the immune response. Several factors, including the characteristics of the protein and the utilization of different adjuvants in animal experiments, may contribute to this disparity. In this study, we investigated the impact of adjuvants on antigen administration in mice, specifically focusing on the stability of the CH2 domain. Consequently, the CH2 domain induced a stronger IgG response in comparison to the stabilized one when using Alum and PBS (without adjuvant). On the other hand, animal experiment using Freund's adjuvant showed the opposite results. These findings indicate the significance of considering the intrinsic conformational stability of a protein when eliciting its immunogenicity, particularly within the context of vaccine development.

Undenatured type II collagen protects against collagen-induced arthritis by restoring gut-joint homeostasis and immunity

Oral administration of harmless antigens can induce suppression of reactive immune responses, a process that capitalises on the ability of the gastrointestinal tract to tolerate exposure to food and commensal microbiome without triggering inflammatory responses. Repeating exposure to type II collagen induces oral tolerance and inhibits induction of arthritis, a chronic inflammatory joint condition. Although some mechanisms underlying oral tolerance are described, how dysregulation of gut immune networks impacts on inflammation of distant tissues like the joints is unclear. We used undenatured type II collagen in a prophylactic regime -7.33 mg/kg three times/week- to describe the mechanisms associated with protective oral immune-therapy (OIT) in gut and joint during experimental Collagen-Induced Arthritis (CIA). OIT reduced disease incidence to 50%, with reduced expression of IL-17 and IL-22 in the joints of asymptomatic mice. Moreover, whilst the gut tissue of arthritic mice shows substantial damage and activation of tissue-specific immune networks, oral administration of undenatured type II collagen protects against gut pathology in all mice, symptomatic and asymptomatic, rewiring IL-17/IL-22 networks. Furthermore, gut fucosylation and microbiome composition were also modulated. These results corroborate the relevance of the gut-joint axis in arthritis, showing novel regulatory mechanisms linked to therapeutic OIT in joint disease.

Immunogenicity of Monovalent mRNA-1273 and BNT162b2 Vaccines in Children

The messenger RNA (mRNA)-based coronavirus disease 2019 vaccines approved for use in children <5 years of age have different antigen doses and administration schedules that could affect vaccine immunogenicity and effectiveness. We sought to compare the strength and breadth of serum binding and neutralizing antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) elicited by monovalent mRNA-based coronavirus disease 2019 vaccines in young children. We conducted a prospective cohort study of children 6 months to 4 years of age who completed primary series vaccination with monovalent mRNA-1273 or BNT162b2 vaccines. Serum was collected 1 month after primary vaccine series completion for the measurement of SARS-CoV-2-specific humoral immune responses, including antibody binding responses to Spike proteins from an ancestral strain (D614G) and major variants of SARS-CoV-2 and antibody neutralizing activity against D614G and Omicronsubvariants (BA.1, BA.4/5). Of 75 participants, 40 (53%) received mRNA-1273 and 35 (47%) received BNT162b2. Children receiving either primary vaccine series developed robust and broad SARS-CoV-2-specific binding and neutralizing antibodies, including to Omicronsubvariants. Children with a previous history of SARS-CoV-2 infection developed significantly higher antibody binding responses and neutralization titers to Omicronsubvariants, which is consistent with the occurrence of identified infections during the circulation of Omicronsubvariants in the region. Monovalent mRNA-1273 and BNT162b2 elicited similar antibody responses 1 month after vaccination in young children. In addition, previous infection significantly enhanced the strength of antibody responses to Omicronsubvariants. The authors of future studies should evaluate incorporation of these vaccines into the standard childhood immunization schedule.

A novel microporous biomaterial vaccine platform for long-lasting antibody mediated immunity against viral infection

Current antigen delivery platforms, such as alum and nanoparticles, are not readily tunable, thus may not generate optimal adaptive immune responses. We created an antigen delivery platform by loading lyophilized Microporous Annealed Particle (MAP) with aqueous solution containing target antigens. Upon administration of antigen loaded MAP (VaxMAP), the biomaterial reconstitution forms an instant antigen-loaded porous scaffold area with a sustained release profile to maximize humoral immunity. VaxMAP induced CD4+ T follicular helper (Tfh) cells and germinal center (GC) B cell responses in the lymph nodes similar to Alum. VaxMAP loaded with SARS-CoV-2 spike protein improved the magnitude, neutralization, and duration of anti-receptor binding domain antibodies compared to Alum vaccinated mice. A single injection of Influenza specific HA1-loaded-VaxMAP enhanced neutralizing antibodies and elicited greater protection against influenza virus challenge than HA1-loaded-Alum. Thus, VaxMAP is a platform that can be used to promote adaptive immune cell responses to generate more robust neutralizing antibodies, and better protection upon pathogen challenge.

Mucosal Immunization with Spore-Based Vaccines against Mannheimia haemolytica Enhances Antigen-Specific Immunity.

Mannheimia haemolytica is a bovine respiratory pathogen commonly associated with bacterial bronchopneumonia. Current vaccine strategies have shown variable efficacy in feedlot cattle, and therefore novel vaccines are needed. Bacillus subtilis spores have been investigated as a mucosal vaccine platform, due to their ability to bind and present antigens to the mucosa and act as an adjuvant. The aim of this study was to develop two spore-based mucosal vaccines targeting M. haemolytica and evaluate their immunogenicity in mice. Two antigen constructs composed of cholera toxin B subunit, M. haemolytica leukotoxin, and either the M. haemolytica outer membrane protein PlpE (MhCP1) or GS60 (MhCP2) were synthesized, purified and then bound to spores as vaccines. In two separate mice trials, the spore-bound vaccines (Spore-MhCP1 and Spore-MhCP2) were administered to mice through intranasal and intragastric routes, while free antigens were administered intranasally and intramuscularly. Unbound spores were also evaluated intranasally. Antigen-specific serum IgG and mucosal IgA from bronchoalveolar lavage, feces, and saliva were measured after vaccination. Mice sera from all treatment groups were assessed for their bactericidal activity against M. haemolytica. In both mice experiments, intramuscular immunization induced the strongest serum IgG antibody response. However, the intranasal administration of Spore-MhCP1 and Spore-MhCP2 elicited the greatest secretory IgA-specific response against leukotoxin, PlpE, and GS60 in bronchoalveolar lavage, saliva, and feces (p < 0.05). Compared to the intranasal administration of free antigen, spore-bound antigen groups showed greater bactericidal activity against M. haemolytica (p < 0.05). Since intranasally delivered Spore-MhCP1 and Spore-MhCP2 elicited both systemic and mucosal immune responses in mice, these vaccines may have potential to mitigate lung infection in cattle by restricting M. haemolytica colonization and proliferation in the respiratory tract. The efficacy of these mucosal spore-based vaccines merits further assessment against M. haemolytica in cattle.

Oral administration of ovalbumin ameliorates specific food allergy via inhibiting gasdermin C-mediated pyroptosis and regulating microbial homeostasis

Early intervention with food allergenic proteins is considered the most promising and effective approach in preventing the onset of food allergy (FA). However, the effects of oral administration of protein antigens from different food sources on specific FA outcomes and its regulatory mechanisms remain largely unclear. Here, the Balb/c mice were treated with 5 mg of egg ovalbumin (OVA) or cow's milk β-lactoglobulin (BLG) for 5 days prior to intraperitoneal sensitization with OVA/Alum and oral challenge with 20 mg OVA. The results indicated that oral administration of both OVA and BLG significantly increased the proportion of regulatory T cells. However, the introduction of OVA, but not the bystander antigen BLG, prevented the occurrence of allergic diarrhea (OT-OVA group: 0% vs OT-BLG group: 100%) and mitigated the decrease in body temperature (OT-OVA group: 0.11 °C vs OT-BLG group: 1.1 °C). Specifically, the levels of serum immunoglobulin-E and mast cell protease-1 were significantly reduced, and the expression of zonula occludens-1, occludin, and claudin-1 was increased in the OVA-treated mice but not BLG-treated mice. Subsequently, transcriptome sequencing and Western blot analysis revealed that oral administration of OVA reduced the expression and cleavage of gasdermin C, which further decreased interleukin-33 secretion. Additionally, the dysregulation of the gut microbiota and short-chain fatty acid metabolism in the intestinal microenvironment caused by FA was reversed in OVA-treated mice but not BLG. In summary, our results presented a unique approach to ameliorate FA through targeting gasdermin C-mediated pyroptosis and dysbiosis of the gut microbiota in the intestinal microenvironment with OVA.

Polydopamine-based nano adjuvant as a promising vaccine carrier induces significant immune responses against Acinetobacter baumannii-associated pneumonia

The objective of this study was to assess the effectiveness of polydopamine nanoparticles (PDANPs) as a delivery system for intranasal antigen administration to prevent Acinetobacter baumannii (A. baumannii)-associated pneumonia. In the in vitro phase, the conserved outer membrane protein 22 (Omp22)-encoding gene of A. baumannii was cloned, expressed, and purified, resulting in the production of recombinant Omp22 (rOmp22), which was verified using western blot. PDANPs were synthesized using dopamine monomers and loaded with rOmp22 through physical adsorption. The rOmp22-loaded PDANPs were characterized in terms of size, size distribution, zeta potential, field emission scanning electron microscopy (FESEM), loading capacity, Fourier transform infrared spectroscopy (FTIR), release profile, and cytotoxicity. In the in vivo phase, the adjuvant effect of rOmp22-loaded PDANPs was evaluated in terms of eliciting immune responses, including humoral and cytokine levels (IL-4, IL-17, and IFN-γ), as well as protection challenge. The rOmp22-loaded PDANPs were spherical with a size of 205 nm, a zeta potential of −14 mV, and a loading capacity of approximately 35.7 %. The released rOmp22 from nontoxic rOmp22-loaded PDANPs over 20 days was approximately 41.5 %, with preserved rOmp22 integrity. The IgG2a/IgG1 ratio and IFN-γ levels were significantly higher in immunized mice with rOmp22-loaded-PDANPs than in rOmp22-alum, naive Omp22, and control groups. Furthermore, rOmp22-loaded PDANPs induced effective protection against infection in the experimental challenge and showed more normal structures in the lung histopathology assay. The results of this study suggest the potential of PDANPs as a nano-adjuvant for inducing strong immune responses to combat A. baumannii.

Care Pathway at a Cancer Center for the Administration of Radiometabolic Therapy with 177Lu-PSMA in Patients with Metastatic Castration-resistant Prostate Cancer.

To present a clinical care model for the administration of 177Lu-labeled prostate-specific membrane antigen (PSMA) in radiometabolic therapy for metastatic castration-resistant prostate cancer (mCRPC) at the National Cancer Institute (NCI) of Bogotá, Colombia. A care model was designed for patients with mCRPC based on the VISION study, a prospective, phase III, multicenter, open-label, randomized study in patients with positive 68Ga-PSMA positron emission tomography/computed tomography who had progressed to taxane and androgen therapy, to receive 177Lu-PSMA-617 combined with the best standard of care vs. the best standard of care alone. The care pathway provided to patients was developed by the Nuclear Medicine Group of the NCI and is the result of adjustments and improvements in the care process and the updating of the literature. A systematic and efficient care model was formalized and implemented for the administration of 177Lu-PSMA therapy in patients with mCRPC who had previously been treated with at least one androgen receptor pathway inhibitor and one or two taxane regimens, with evidence of disease progression. An optimized process of care based on the determinants of clinical outcomes was developed for patients who received this type of radiometabolic therapy.

Stable expression of HIV-1 MPER extended epitope on the surface of the recombinant probiotic bacteria Escherichia Coli Nissle 1917 using CRISPR/Cas9

BackgroundMucosal vaccines have the potential to induce protective immune responses at the sites of infection. Applying CRISPR/Cas9 editing, we aimed to develop a probiotic-based vaccine candidate expressing the HIV-1 envelope membrane-proximal external region (MPER) on the surface of E. coli Nissle 1917.ResultsThe HIV-1 MPER epitope was successfully introduced in the porin OmpF of the E. coli Nissle 1917 (EcN-MPER) and the modification was stable over 30 passages of the recombinant bacteria on the DNA and protein level. Furthermore, the introduced epitope was recognized by a human anti-HIV-1 gp41 (2F5) antibody using both live and heat-killed EcN-MPER, and this antigenicity was also retained over 30 passages. Whole-cell dot blot suggested a stronger binding of anti-HIV-1 gp41 (2F5) to heat-killed EcN-MPER than their live counterpart. An outer membrane vesicle (OMV) – rich extract from EcN-MPER culture supernatant was equally antigenic to anti-HIV-1 gp41 antibody which suggests that the MPER antigen could be harboured in EcN-MPER OMVs. Using quantitative ELISA, we determined the amount of MPER produced by the modified EcN to be 14.3 µg/108 cfu.ConclusionsThe CRISPR/Cas9 technology was an effective method for establishment of recombinant EcN-MPER bacteria that was stable over many passages. The developed EcN-MPER clone was devoid of extraneous plasmids and antibiotic resistance genes which eliminates the risk of plasmid transfer to animal hosts, should this clone be used as a vaccine. Also, the EcN-MPER clone was recognised by anti-HIV-1 gp41 (2F5) both as live and heat-killed bacteria making it suitable for pre-clinical evaluation. Expression of OmpF on bacterial surfaces and released OMVs identifies it as a compelling candidate for recombinant epitope modification, enabling surface epitope presentation on both bacteria and OMVs. By applying the methods described in this study, we present a potential platform for cost-effective and rational vaccine antigen expression and administration, offering promising prospects for further research in the field of vaccine development.

Oral Administration of Antigen Prevents Allergic Sensitization through Skin and Airways by Suppressing T Follicular Helper Cell Development

Oral Administration of Antigen Prevents Allergic Sensitization through Skin and Airways by Suppressing T Follicular Helper Cell Development

Anti-inflammatory role of APRIL by modulating regulatory B cells in antigen-induced arthritis.

APRIL (A Proliferation-Inducing Ligand), a member of the TNF superfamily, was initially described for its ability to promote proliferation of tumor cells in vitro. Moreover, this cytokine has been related to the pathogenesis of different chronic inflammatory diseases, such as rheumatoid arthritis. This study aimed to evaluate the ability of APRIL in regulating B cell-mediated immune response in the antigen-induced arthritis (AIA) model in mice. AIA was induced in previously immunized APRIL-transgenic (Tg) mice and their littermates by administration of antigen (mBSA) into the knee joints. Different inflammatory cell populations in spleen and draining lymph nodes were analyzed using flow cytometry and the assay was performed in the acute and chronic phases of the disease, while cytokine levels were assessed by ELISA. In the acute AIA, APRIL-Tg mice developed a less severe condition and a smaller inflammatory infiltrate in articular tissues when compared with their littermates. We also observed that the total cellularity of draining lymph nodes was decreased in APRIL-Tg mice. Flow cytometry analysis revealed an increase of CD19+IgM+CD5+ cell population in draining lymph nodes and an increase of CD19+CD21hiCD23hi (B regulatory) cells in APRIL-Tg mice with arthritis as well as an increase of IL-10 and CXCL13 production in vitro.

Brain‐derived neurotrophic factor alleviates clinical symptoms of experimental autoimmune uveoretinitis and supports retinal regeneration

Purpose: Brain‐derived neurotrophic factor (BDNF) is one of the most important neurotrophins that has a fundamental role in the regulation of neuronal growth, proliferation, and regeneration, as well as an important modulatory effect on the immune cells. In addition, BDNF potentiates the neurodifferentiation of Müller cells (MCs), thus supporting retinal regeneration. Therefore, we aimed to investigate the anti‐inflammatory effect of BDNF in experimental autoimmune uveoretinitis (EAU), a severe neuroinflammatory condition, and whether BDNF could facilitate the regenerative capacity of MCs in EAU.Methods: EAU in mice was induced by s.c. administration of retinal antigen IRBP1‐20 emulsified in a complete Freud's adjuvant, followed by i.v. administration of Pertussis toxin. BDNF was administered daily in the form of eye drops from day 8 to day 14 after immunization. On day 14, fundoscopy was performed to assess clinical signs of EAU. Mice were then euthanized, and their eyes and retinas were isolated for further Western blot, RT‐qPCR, flow cytometry, and immunohistochemistry analyses.Results: The treatment with BDNF significantly improved the clinical manifestations of EAU, including optic disc oedema, vasculitis, and inflammatory infiltrates in the retina. BDNF significantly decreased the infiltration of CD4+ T cells, CD8+ T cells, and CD11b+ myeloid cells into the retina and also suppressed the expression of several pro‐inflammatory cytokines and chemokines. In addition, BDNF administration significantly increased the expression of markers of neurogenesis in retinal MCs.Conclusions: Together, our results demonstrate that BDNF has important anti‐inflammatory and neurogenic properties and that it may serve as a promising target for developing novel therapeutic strategies for neurodegenerative and neuroinflammatory diseases of the retina.Support.This study was supported by the following grant projects: GAUK 378421, 260 648/SVV/2023, and COOPERATIO Neurosciences.