Immunogenic Proteins Research Articles

Structure-guided design and evaluation of CRM197-scaffolded vaccine targeting GnRH for animal immunocastration

Immunocastration is a humane alternative to surgical castration for controlling population and estrous behaviors in animals. Gonadotropin-releasing hormone (GnRH), the pivotal initiating hormone of the hormonal cascade in mammals, is the optimal target for immunocastration vaccine development. Cognate antigen-mediated cross-linking of B cell receptors (BCRs) is a strong activation signal for B cells and is facilitated by repetitive surface organizations of antigens. In this study, we describe the structure-guided design of highly immunogenic chimeric proteins with variant numbers of GnRH peptide insertion by epitope grafting. Linear B-cell epitopes of cross-reacting material 197 (CRM197) were replaced with multiple copies of GnRH peptide, and the inserts were displayed on the surface of the designs while maintaining the overall folding of CRM197. Among the seven designs, TCG13, which carries 13 copies of GnRH peptide, was the most immunogenic, and its immunocastration efficacy was evaluated in male mice. Vaccination with the BFA03-adjuvanted TCG13 induced potent humoral immunity and reduced the serum testosterone concentration in mice. It could significantly decrease sperm quality and severely impair gonadal function and fertility. These results demonstrate that CRM197 holds great value as a scaffold for epitope presentation in peptide-based vaccine development and supports TCG13 as a promising vaccine candidate for animal immunocastration.Key points• Provide a feasible way to design chimeric immunogen targeting GnRH by epitope grafting.• CRM197 can accommodate the insertion of multiple copies of heterologous epitope peptides.• Administration with the most immunogenic design led to effective immunocastration in male mice.

Application of a liposomal subunit vaccine in chickens for reduction of Campylobacter gut colonisation

Abstract Introduction Campylobacter are the most common cause of food poisoning, which manifests itself in diarrhoea of varying severity. Additionally, because of the increasing number of people with immune deficiencies, more frequent serious complications of Campylobacter infections are being observed. The main source of infection is the consumption of contaminated poultry meat, which is a consequence of the insufficiency of current hygiene and biosecurity to control Campylobacter or eliminate it from the poultry food chain. Material and Methods Two hybrid proteins, presenting selected epitopes of the Campylobacter antigens CjaD and EF-Tu, were developed based on the highly immunogenic proteins CjaA and CjaC. Four groups of chickens were vaccinated with different preparations (a mixture of both hybrid proteins encapsulated in anionic or neutral liposomes) and different doses (a single dose given on the day of hatching or two doses given on days 1 and 14 of life). The number of Campylobacter was assessed in the intestinal contents of vaccinated birds. Results No statistically significant differences in colonisation levels were observed between chickens immunised with neutral liposomes containing hybrid proteins and their non-immunised counterparts, regardless of dosage regimen. Conclusion Although immunisation of chickens did not produce the expected results, the approach used has great potential, which is worth further investigation and development.

Non‐Natural MUC1 Glycopeptide Homogeneous Cancer Vaccine with Enhanced Immunogenicity and Therapeutic Activity

AbstractGlycopeptides derived from the glycoprotein mucin‐1 (MUC1) have shown potential as tumor‐associated antigens for cancer vaccine development. However, their low immunogenicity and non‐selective conjugation to carriers present significant challenges for the clinical efficacy of MUC1‐based vaccines. Here, we introduce a novel vaccine candidate based on a structure‐guided design of an artificial antigen derived from MUC1 glycopeptide. This engineered antigen contains two non‐natural amino acids and has an α‐S‐glycosidic bond, where sulfur replaces the conventional oxygen atom linking the peptide backbone to the sugar N‐acetylgalactosamine. The glycopeptide is then specifically conjugated to the immunogenic protein carrier CRM197 (Cross‐Reactive Material 197), a protein approved for human use. Conjugation involves selective reduction and re‐bridging of a disulfide in CRM197, allowing the attachment of a single copy of MUC1. This strategy results in a chemically defined vaccine while maintaining both the structural integrity and immunogenicity of the protein carrier. The vaccine elicits a robust Th1‐like immune response in mice and generates antibodies capable of recognizing human cancer cells expressing tumor‐associated MUC1. When tested in mouse models of colon adenocarcinoma and pancreatic cancer, the vaccine is effective both as a prophylactic and therapeutic use, significantly delaying tumor growth. In therapeutic applications, improved outcomes were observed when the vaccine was combined with an anti‐programmed cell death protein 1 (anti‐PD‐1) checkpoint inhibitor. Our strategy reduces batch‐to‐batch variability and enhances both immunogenicity and therapeutic potential. This site‐specific approach disputes a prevailing dogma where glycoconjugate vaccines require multivalent display of antigens.

An optimized ROP6 mRNA construct successfully expressed immunogenic Toxoplasma gondii ROP6 protein in cell culture

Toxoplasma gondii is an apicomplexan parasite infecting all mammals including humans and causes toxoplasmosis. There is no vaccine available for humans and thus vaccine development efforts continue using novel antigens and/or vaccine platforms. Since our previous microarray screening study showed that ROP6 is a suitable antigen to be used in vaccine studies, in this study, we aimed to design an optimized mRNA construct encoding the ROP6 protein and then demonstrate its efficiency and immunogenicity using in vitro methods. For this, we constructed a pT7CFE1-Chis/ROP6 vector encoding optimized ROP6 mRNA containing EMCV 5′UTR with IRES and a 20 nucleotides fragment from alpha globin 3′ UTR. Then, we generated the optimized ROP6 mRNAs with anti-reverse cap analogue (ARCA) and approximately 150 nucleotide long poly-A tail. Next, HEK293T cells were transfected with the optimized ROP6 mRNAs to show recombinant ROP6 protein expression capability. Moreover, we expressed in vitro recombinant ROP6 protein in HeLa cell lysate using the pT7CFE1-Chis/ROP6 vector to reveal the immunogenicity of recombinant ROP6 protein using sera samples collected from mice infected with PRU strain of T. gondii. The IFA and Western blot results showed that the optimized ROP6 mRNAs successfully expressed the recombinant ROP6 protein in HEK293T cells. Moreover the recombinant ROP6 protein expressed in HeLa cell lysate strongly reacted with sera samples collected from mice. The absorbance difference detected among positive and negative mice serum samples analyzed was statistically significant, indicating that the recombinant ROP6 protein was immunogenic (P = 0.0003). In conclusion, this study demonstrated that the optimized ROP6 mRNAs can be used in the development of mRNA vaccines against toxoplasmosis.

Mesomycoplasma (Mycoplasma) ovipneumoniae dihydrolipoamide dehydrogenase is an immunogenic plasminogen binding protein and a putative adhesin

The interaction of Mesomycoplasma (Mycoplasma) ovipneumoniae (M. ovipneumoniae) with host cells is a pivotal step in the infection process, underlining the necessity to develop vaccines and therapeutic approaches targeting the pathogen's key invasion mechanisms. The bacterium's capacity for adherence, invasion, and subsequent evasion of the host immune response underpins its pathogenicity, rendering adherence genes feasible vaccine targets. This study focuses on pyruvate dehydrogenase complex component E3 (PdhD), a membrane-anchored surface protein implicated in these pathogenic processes. Bioinformatics analysis reveals the conservation of PdhD sequence within M. ovipneumoniae. Membrane protein extraction, immunoblotting and ELISA assay have confirmed the presence of PdhD on the M. ovipneumoniae surface and cytoplasm, suggesting its multifunctionality. Our research employed antibody inhibition assays to characterize the bacterial adhesion suppression by anti-PdhD antibodies, complemented by bactericidal complement assays, supporting its candidacy as a putative vaccine target. The ELISA binding assay substantiated that PdhD binded to plasminogen (Plg) in a dose-dependent manner. Notably, PdhD is also involved in biofilm formation. The inhibitory effect of anti-PdhD sera on biofilm formation is congruent with novel therapeutic strategies targeting related mycoplasmas. This study reports the characterization of the first virulence-associated protein PdhD of M. ovipneumoniae and suggests its potential as a vaccine target to combat M. ovipneumoniae infection.

Impact of protein aggregation on the immunogenicity of a human monoclonal antibody following pulmonary administration in mice

Spray drying is a widely employed method for generating dry powder formulations for inhalation. Yet, it presents substantial challenges when applied to therapeutic proteins due to stability issues. The formation of protein aggregates during the atomization and the heating steps can diminish protein activity and raise immunogenicity concerns. Here, we assessed the impact of varying levels of protein aggregates generated during spray-drying on the fate and the immunogenicity of the human monoclonal antibody NIP228 following intratracheal administration in mice. Aggregate-free rhodamine labelled NIP228 was spray-dried with or without 1% polysorbate 80 surfactant, resulting in the generation of powder formulations with associated low and high protein aggregate levels, respectively. Confocal imaging highlighted the presence of aggregates in the lungs for both powders but not for the solution, while flow cytometry analysis designated alveolar macrophages as the main immune cells taking up rhod-NIP228 in the lungs with very little involvement of dendritic cells and interstitial macrophages following a single dose administration. Notably, repeated intratracheal administration of the three formulations in mice did not impact the magnitude of the anti-drug antibody response in sera or broncho-alveolar lavages. The pulmonary route appeared to evoke a more robust immune response when compared to subcutaneous administration. Overall, the level of NIP228 aggregation in this study did not appear to be the primary driver of NIP228 immunogenicity following delivery to the lungs in mice, shedding new light on the interplay between protein aggregation and immunogenicity in the context of the pulmonary delivery of therapeutic proteins.

Unraveling the full impact of SPD_0739: a key effector in S. pneumoniae iron homeostasis.

S. pneumoniae obtains growth essential iron from hemoglobin and other host hemoproteins. Still, the bacterial mechanisms involved are only partially understood, and there are inconsistent reports regarding the function of several transporters implicated in iron uptake. In this study, we clarified the role of PnrA/Spbhp-37, a ligand-binding protein previously linked to nucleoside or heme by different studies. We present data supporting a role in nucleoside scavenging rather than heme import and reveal that PnrA/Spbhp-37 modulates iron and heme uptake, likely by influencing the nucleoside cellular pool. Hence, this work provides a new understanding of a process critical to the pathophysiology of a significant human pathogen. Moreover, PnrA/Spbhp-37 is an abundant and immunogenic surface protein that is highly conserved. Hence, this study also clarifies the function of a promising vaccine target.

Immunoproteomics: Approach to Diagnostic and Vaccine Development.

The study of large protein sets (proteomics) involved in the immunological reaction is known as immunoproteomics. The methodology of immunoproteomics plays a major role in identifying possible vaccine candidates that could protect against pathogenic infection. The study of immunogenic proteins that are expressed during the outset of infection is the focus of the crosstalk between proteomics and immune protection antigens utilizing serum. Peptide presentation by MHC provides the new 'window' into changes that occur in the cell. Thus, there is strong, intense pressure on the pathogen that has been mutated in such an unusual manner that it can bypass the MHC peptide presentation by the MHC molecule. The pathogen's ability to evade the immune system is strongly restricted by the two unique distinct properties of MHC molecules, i.e., polygenic and polymorphic properties. MHC-I restriction epitope identification has traditionally been accomplished using genetic motif prediction. The study of immune system proteins and their interactions is the main emphasis of the specialist field of immunoproteomics within proteomics. Methodologies include mass spectrometry (MS), SRM assay, MALDI-TOF, Chromatography, ELISA, 2DG PAGE, and bioinformatics tools. Challenges are the complexity of the immune system, protein abundance and dynamics, sample variability, post-translational modifications (PTMs), and data integration. Current advancements are enhanced mass spectrometry techniques, single-cell proteomics, artificial intelligence and machine learning, advanced protein labeling techniques, integration with other omics technologies, and functional proteomics. However, the recently emerging field of immunoproteomics has more promising possibilities in the field of peptide-based vaccines and virus-like particle vaccines. The importance of immunoproteomics technologies and methodologies, as well as their use in the field of vaccinomics, are the main topics of this review. Here, we have discussed immunoproteomics in relation to a step towards the future of vaccination.

A Fentanyl Hapten‐Displaying Lipid Nanoparticle Vaccine that Non‐Covalently Encapsulates a TLR7/8 Agonist and T‐helper Epitope Induces Protective Anti‐Fentanyl Immunity

Opioid use disorder ‐ particularly involving fentanyl ‐ has precipitated a public health crisis characterized by a significant increase in addiction and overdose‐related deaths. Fentanyl‐specific immunotherapy, which aims at inducing fentanyl‐specific antibodies capable of binding fentanyl molecules in the bloodstream, preventing their entry in the central nervous system, is therefore gaining momentum. Conventional opioid designs rely on the covalent conjugation of fentanyl analogues to immunogenic carrier proteins that hold the inherent capacity of mounting immunodominant responses. Here, we present an alternative fentanyl vaccine design that utilizes a non‐covalent assembly of lipid nanoparticles (LNPs) to deliver fentanyl haptens in conjunction with a CD4+ T‐helper peptide epitope and an imidazoquinoline TLR7/8 agonist. Our results demonstrate that a single intramuscular administration of the LNP‐based nanovaccine elicits fentanyl‐specific antibodies, significantly mitigating the effects of opioid overdose in preclinical mouse models. Furthermore, we analyzed the immunobiological behavior of the vaccine in vivo in mouse models, providing evidence that covalent attachment of a fentanyl hapten to a carrier proteins or peptide epitope is not necessary for inducing an effective immune response. However, co‐delivery ‐ specifically, the physical assembly of all immune cues into an LNP ‐ remains essential for inducing hapten‐specific immunity.

A Fentanyl Hapten-Displaying Lipid Nanoparticle Vaccine that Non-Covalently Encapsulates a TLR7/8 Agonist and T-helper Epitope Induces Protective Anti-Fentanyl Immunity.

Opioid use disorder - particularly involving fentanyl - has precipitated a public health crisis characterized by a significant increase in addiction and overdose-related deaths. Fentanyl-specific immunotherapy, which aims at inducingfentanyl-specificantibodies capable of binding fentanyl molecules in the bloodstream, preventing their entry in the central nervous system, is therefore gaining momentum.Conventional opioid designsrely on the covalent conjugation of fentanyl analogues to immunogenic carrier proteins that hold the inherent capacity of mounting immunodominant responses. Here, we present an alternative fentanyl vaccine design that utilizes a non-covalent assembly of lipid nanoparticles (LNPs) to deliver fentanyl haptens in conjunction with a CD4+T-helper peptide epitope and an imidazoquinoline TLR7/8 agonist. Our results demonstrate that a single intramuscular administration of the LNP-based nanovaccine elicits fentanyl-specific antibodies, significantly mitigating the effects of opioid overdose in preclinical mouse models. Furthermore, we analyzed the immunobiological behavior of the vaccine in vivo in mouse models, providing evidence that covalent attachment of a fentanyl hapten to a carrier proteins or peptide epitope is not necessary for inducing an effective immune response. However, co-delivery - specifically, the physical assembly of all immune cues into an LNP - remains essential for inducing hapten-specific immunity.

Glycopolymeric Nanoparticles Enrich Less Immunogenic Protein Coronas, Reduce Mononuclear Phagocyte Clearance, and Improve Tumor Delivery Compared to PEGylated Nanoparticles.

Nanoparticles (NPs) offer significant promise as drug delivery vehicles; however, their in vivo efficacy is often hindered by the formation of a protein corona (PC), which influences key physiological responses such as blood circulation time, biodistribution, cellular uptake, and intracellular localization. Understanding NP-PC interactions is crucial for optimizing NP design for biomedical applications. Traditional approaches have utilized hydrophilic polymer coatings like polyethylene glycol (PEG) to resist protein adsorption, but glycopolymer-coated nanoparticles have emerged as potential alternatives due to their biocompatibility and ability to reduce the adsorption of highly immunogenic proteins. In this study, we synthesized and characterized glycopolymer-based poly[2-(diisopropylamino)ethyl methacrylate-b-poly(methacrylamidoglucopyranose) (PDPA-b-PMAG) NPs as an alternative to PEGylated NPs. We characterized the polymers using a range of techniques to establish their molecular weight and chemical composition. PMAG and PEG-based NPs showed equivalent physicochemical properties with sizes of ∼100 nm, spherical morphology, and neutral surface charges. We next assessed the magnitude of protein adsorption on both NPs and catalogued the identity of the adsorbed proteins using mass spectrometry-based techniques. The PMAG NPs were found to adsorb fewer proteins in vitro as well as fewer immunogenic proteins such as Immunoglobulins and Complement proteins. Flow cytometry and confocal microscopy were employed to examine cellular uptake in RAW 264.7 macrophages and MDA-MB-231 tumor cells, where PMAG NPs showed higher uptake into tumor cells over macrophages. In vivo studies in BALB/c mice with orthotopic 4T1 breast cancer xenografts showed that PMAG NPs exhibited prolonged circulation times and enhanced tumor accumulation compared to PEGylated NPs. The biodistribution analysis also revealed greater selectivity for tumor tissue over the liver for PMAG NPs. These findings highlight the potential of glycopolymeric NPs to improve tumor targeting and reduce macrophage uptake compared to PEGylated NPs, offering significant advancements in cancer nanomedicine and immunotherapy.

Genomic Analysis of Aeromonas salmonicida ssp. salmonicida Isolates Collected During Multiple Clinical Outbreaks Supports Association with a Single Epidemiological Unit.

Outbreaks of furunculosis cause significant losses in salmonid aquaculture worldwide. With a recent rise in antimicrobial resistance, regulatory measures to minimize the use of antibiotics in animal husbandry, including aquaculture, have increased scrutiny and availability of veterinary medical products to control this disease in production facilities. In such a regulatory environment, the utility of autogenous vaccines to assist with disease prevention and control as a veterinary-guided prophylactic measure is of high interest to the producers and veterinary services alike. However, evolving concepts of epidemiological units and epidemiological links need to be considered during approval and acceptance procedures for the application of autogenous vaccines in multiple aquaculture facilities. Here, we present the results of solid-state nanopore sequencing (Oxford Nanopore Technologies, ONT) performed on 54 isolates of Aeromonas salmonicida ssp. salmonicida sampled during clinical outbreaks of furunculosis in different aquaculture facilities from Bavaria, Germany, from 2017 to 2020. All of the performed analyses (phylogeny, single nucleotide polymorphism and 3D protein modeling for major immunogenic proteins) support a high probability that all studied isolates belong to the same epidemiological unit. Simultaneously, we describe a cost/effective method of whole genome analysis with the usage of ONT as a viable strategy to study outbreaks of other pathogens in the field of aquatic veterinary medicine for the purpose of developing the best autogenous vaccine candidates applicable to multiple aquaculture establishments.

Breakthrough in allergy mitigation using an innovative steam pressure-based processing technique

Peanuts are recognized as one of the most common allergenic foods, known to induce severe Th2-mediated allergic reactions. The resulting global health concern has fostered the necessity to design innovative technologies capable of mitigating allergenicity. This study investigated the effect of an innovative thermomechanical process, “Intensification of Vaporization by Decompression to the Vacuum” (IVDV), on the protein content and immunogenicity of whole peanuts. Through animal studies using peanut allergy BALB/c mouse models, this research revealed a clear reduction in allergic symptoms once challenged with IVDV-treated peanut protein extract, compared to those receiving raw or deep-fried peanut protein extracts. Significant changes in immune response markers in animals were observed, including reduced levels of histamine, Th1/Th2 cytokines, and antibodies, thus confirming the efficacy of IVDV in mitigating allergenicity in peanuts. Saturated steam pressure was demonstrated to have a highly significant positive effect on the reduction of protein content in IVDV-treated samples through degradation, with a noteworthy reduction ranging from 42.3% to 89.2%. This pilot study embarked on a pioneering exploration into the ability of IVDV to offer a viable solution in reducing peanut allergenicity, opening new avenues for enhanced food safety and inclusivity. The ease of scalability of IVDV technology to an industrial level, along with its cost-efficiency, further enhance its appeal for widespread adoption.

Optimisation of induction and purification protocols of recombinant 22.6kDa tegumental protein of Schistosoma spindale inprokaryotic vector

Schistosomosis is a prevalent zoonotic parasitic disease affecting both humans and animals on a global scale, with an estimated 165 million cattle and 200 million people impacted worldwide. Eventhough, serological methodologies designed for the identification of specific antibodies targeting parasitic antigens are esteemed for their high sensitivity, there are criticisms due to their incapacity to reliably indicate active infection, inability to correlate with the intensity of infection and lack of specificity. Enhancing the specificity of serological assays presents a significant challenge, primarily attributable to the identification and synthesis of specific antigens. In addressing these limitations, recombinant technology with specific immunogenic proteins as candidate antigens emerges as a viable alternative. In this study, induction of 22.6 kDa recombinant tegument protein of Schistosoma spindale was achieved using 0.6 mM concentration of IPTG at 37°C for four hours. Nickel chelating affinity chromatography was employed for protein purification, yielding maximum protein concentration at 75mM elution. Subsequently, the dialysis technique was employed to remove contaminants, while lyophilisation method was employed for protein concentration. The protein concentration post dialysis was measured at 0.220 mg/mL, while lyophilisation resulted in a concentration of 2mg/m Keywords: 22.6 kDa tegumental protein, Schistosoma spindale, dialysis, lyophilisation

Trivalent outer membrane vesicles-based combination vaccine candidate induces protective immunity against Campylobacter and invasive non-typhoidal Salmonella in adult mice.

Campylobacter and invasive non-typhoidal Salmonella (iNTS) are among the most common causative agents of gastroenteritis worldwide. As of now, no single combination licensed vaccine is available for public health use against both iNTS and Campylobacter species. Outer-membrane vesicles (OMVs) are nanoscale proteoliposomes released from the surface of gram-negative bacteria during log phase and harbor a variety of immunogenic proteins. Based on epidemiology of infections, we formulated a novel trivalent outer membrane vesicles (TOMVs)-based vaccine candidate against Campylobacter jejuni (CJ), Salmonella Typhimurium (ST) and Salmonella Enteritidis (SE). Isolated OMVs from CJ, ST and SE were combined in equal ratios for formulation of TOMVs and 5µg of the developed vaccine candidate was used for intraperitoneal immunization of adult BALB/c mice. Immunization with TOMVs significantly activated both the humoral and cellular arm of adaptive immune response. Robust bactericidal effect was elicited by TOMVs immunized adult mice sera. TOMVs immunization induced long-term protective efficacy against CJ, ST and SE infections in mice. The study illustrates the ability of TOMVs-based combination immunogen in eliciting broad-spectrum protective immunity against prevalent Campylobacter and iNTS pathogens. According to the findings, TOMVs can work as a potent combination-based acellular vaccine candidate for amelioration of Campylobacter and iNTS-mediated gastroenteritis.

Functional genomic analysis of the 68-1 RhCMV-Mycobacteria tuberculosis vaccine reveals an IL-15 response signature that is conserved with vector attenuation.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) is a deadly infectious disease having a major impact on global health. Using the CMV vector for development of novel vaccines is a promising new strategy that elicits strong and durable, high frequency memory T cell responses against heterologous immunogens. We conducted functional transcriptomic analysis of whole blood samples collected from cohorts of rhesus (Rh) macaques that were administered RhCMV/TB vector using a prime-boost strategy. Two modified CMV vectors were used in this study, including 68-1 RhCMV/TB-6Ag (encoding 6 Mtb protein immunogens, including Ag85A, ESAT-6, Rv3407, Rv2626, Rpf A, and Rpf D) and its attenuated variant, 68-1 RhCMV/Δpp71-TB-6Ag (a cell-to-cell spread-deficient vaccine vector lacking the Rh110 gene encoding the pp71 tegument protein). Bulk mRNA sequencing, differential gene expression, and functional enrichment analyses showed that these RhCMV/TB vaccines induce the innate and adaptive immune responses with specific transcriptomic signatures, including the IL-15-induced protective gene signature previously defined to be linked with protection against simian immunodeficiency virus (SIV) by the 68-1 RhCMV/SIV vaccine. While both vectors exhibited a transcriptomic response of the IL-15 protective signature in whole blood, we show that lack of pp71 does not maintain induction of the protective signature for the full duration of the study compared to the parental non-attenuated vector. Our observations indicate that RhCMV vector vaccines induce a transcriptomic response in whole blood that include a conserved IL-15 signature of which vector-encoded pp71 is an important component of response durability that upon future Mtb challenge may define specific vaccine protection outcomes against Mtb infection.

Cumulative influence of immunogenic factors, genetic variations, and protein modulations in subacute sclerosing panencephalitis (SSPE): A narrative review

AbstractSubacute sclerosing panencephalitis (SSPE) is a progressive and catastrophic neurodegenerative disorder due to persistent infection with the aberrant measles virus in the brain. The exact etiology of SSPE is still unknown, and early diagnosis remains a challenge, especially with the atypical presentations. The pathogenesis of SSPE involves a complex interplay between viral factors and immunological response of the host. The presenting review demonstrates an extensive glimpse of the immuno‐genetics of SSPE, exploring the single‐nucleotide polymorphisms (SNPs), genetic risk factors and immune responses that influence susceptibility and disease progression.

Extracellular plant subtilases dampen cold-shock peptide elicitor levels.

Recognizing pathogen-associated molecular patterns on the cell surface is crucial for plant immunity. The proteinaceous nature of many of these patterns suggests that secreted proteases play important roles in their formation and stability. Here we demonstrate that the apoplastic subtilase SBT5.2a inactivates the immunogenicity of cold-shock proteins (CSPs) of the bacterial plant pathogen Pseudomonas syringae by cleaving within the immunogenic csp22 epitope. Consequently, mutant plants lacking SBT5.2a activity retain higher levels of csp22, leading to enhanced immune responses and reduced pathogen growth. SBT5.2 sensitivity is influenced by sequence variation surrounding the cleavage site and probably extends to CSPs from other bacterial species. These findings suggest that variations in csp22 stability among bacterial pathogens are a crucial factor in plant-bacteria interactions and that pathogens exploit plant proteases to avoid pattern recognition.

Protection efficacy and immunogenicity of Clostridium chauvoei proteins as a subunit blackleg vaccine or an adjuvant for Clostridium perfringens epsilon toxoid

Potential application of Clostridium chauvoei proteins was studied as a subunit blackleg vaccine or a biological adjuvant for Clostridium perfringens epsilon toxoid vaccine. Extracellular and cell surface proteins were extracted from C. chauvoei culture, and their protective efficacy was evaluated by potency test in guinea pigs. In order to investigate the effect of cell surface proteins on C. perfringens epsilon toxoid immunogenicity, rabbits were inoculated subcutaneously twice with: C. perfringens type D toxoid supernatant + 200 μg C. chauvoei cell surface proteins (PR-200), toxoid supernatant + 400 μg cell surface proteins (PR-400), inactivated C. perfringens type D vaccine (Vac), toxoid supernatant (Tox), or PBS. Isolation of cell surface proteins yielded about 2.5 mg/L culture protein with a sharp band at 43 kDa probably corresponding to flagellin. Potency test demonstrated the protection ability of both cellular and extracellular proteins of C. chauvoei. ELISA showed that the highest antibody titers against epsilon toxoid belonged to PR-400 and Vac groups. The effect of days post immunization on antibody response was not significant. No significant difference was observed between PR-400 and Vac, as well as PR-200 and Tox groups. Clostridium chauvoei cell surface proteins may have the potential for application as a blackleg disease vaccine and an adjuvant for clostridial toxoids.

Inserting CTL Epitopes of the Viral Nucleoprotein to Improve Immunogenicity and Protective Efficacy of Recombinant Protein against Influenza A Virus.

Conserved influenza virus proteins, such as the hemagglutinin stem domain (HA2), nucleoprotein (NP), and matrix protein (M), are the main targets in the development of universal influenza vaccines. Previously, we constructed a recombinant vaccine protein Flg-HA2-2-4M2ehs containing the extracellular domain of the M2 protein (M2e) and the aa76-130 sequence of the second HA subunit as target antigens. It demonstrated immunogenicity and broad protection against influenza A viruses after intranasal and parenteral administration. This study shows that CD8+ epitopes of NP, inserted into a flagellin-fused protein carrying M2e and HA2, affect the post-vaccination immune humoral response to virus antigens without reducing protection. No differences were found between the two proteins in their ability to stimulate the formation of follicular Th in the spleen, which may contribute to a long-lasting antigen-specific humoral response. The data obtained on Balb/c mice suggest that the insertion of CTL NP epitopes into the flagellin-fused protein carrying M2e and HA2 reduces the antibody response to M2e and A/H3N2. In C57Bl6 mice, this stimulates the formation of NP-specific CD8+ Tem and virus-specific mono- and multifunctional CD4+ and CD8+ Tem in the spleen and completely protects mice from influenza virus subtypes A/H1N1pdm09 and A/H3N2.