Protective Immune Response Research Articles

Specific Depletion of Myeloid-Derived Suppressor Cells by the Chemotherapy Agent 5-Fluorouracil Enhances Protective Immune Response in Paracoccidioidomycosis.

Paracoccidioidomycosis (PCM) is regulated by suppressive mechanisms mediated by plasmacytoid-dendritic cells, regulatory T cells and myeloid-derived suppressor cells (MDSCs). MDSC suppressive activity on Th1/Th17 immunity was shown to be mediated by inhibitory effect of IL-10, IDO-1, and PD-L1. Studies revealed the 5-fluorouracil (5-FU) as a selective MDSC apoptosis-inducing agent, but its in vivo effect on infectious processes remains poorly investigated. MDSCs and other leukocytes were evaluated in the lungs of 5-FU-treated mice after 4, 6, and 8 weeks of Paracoccidioides brasiliensis infection. Disease severity and immunological response were evaluated in MDSCs-depleted mice. 5-FU treatment caused a reduction of pulmonary MDSCs and fungal loads. The specific depletion of MDSCs reduced all pulmonary CD4+ T-cell populations resulting in improved tissue pathology and increased survival. This reduction was concomitant with increased frequencies of Th1/Th17 cells and the increased levels of Th1/Th2/Th17 cytokines in the lungs and liver of treated mice, suggesting an early and efficient protective effect of these cells. Furthermore, the immune protection conferred by the 5-FU treatment could be reversed by the MDSC-adoptive transfer. 5-FU depletes MDSCs of P. brasiliensis-infected mice, resulting in enhanced immunity. This protective effect can be viewed as a potential immunotherapeutic tool for PCM.

Immature dendritic cell-targeting mRNA vaccine expressing PfCSP enhances protective immune responses against Plasmodium liver infection.

Resurgence in malaria has been noted in 2022 with 249 million clinical cases resulting in 608,000 deaths, mostly in children under five. Two vaccines, RTS, S, and more recently R21, targeting the circumsporozoite protein (CSP) are recommended by the WHO but are not yet widely available. Strong humoral responses to neutralize sporozoites before they can infect the hepatocytes are important for vaccine-mediated protection. Suboptimal protection conferred by these first-generation vaccines highlight the need for approaches to improve vaccine-induced immune responses. With the recent success of mRNA-LNP vaccines against COVID-19, there is growing interest in leveraging this approach to enhance malaria vaccines. Here, we present the development of a novel chemokine fusion mRNA vaccine aimed at boosting immune responses to PfCSP by targeting the immunogen to immature dendritic cells (iDC). Vaccination of mice with mRNA encoding full-length CSP fused to macrophage inflammatory protein 3 alpha (MIP3α) encapsulated within lipid nanoparticles (LNP) elicited robust CD4 + T cell responses and enhanced antibody titers against NANP repeat epitopes compared to a conventional CSP mRNA-LNP vaccine. Importantly, the CSP-MIP3α fusion vaccine provided significantly greater protection against liver infection upon challenge with P. berghei PfCSP transgenic sporozoites. This enhanced protection was associated with multifunctional CD4 + T cells levels and anti-NANP repeat titers. This study highlights the potential to augment immune responses to PfCSP through iDC targeting and bolster protection against malaria liver infection.

Nematode Galectin Inhibits Basophilic Leukaemia RBL-2H3 Cells Apoptosis in IgE-Mediated Activation.

Mast cells are essential immune cells involved in the host's defence against gastrointestinal nematodes. To evade the immune response, parasitic nematodes produce a variety of molecules. Galectin 1, produced by Teladorsagia circumcincta (Tci-gal-1), reduces mast cell degranulation and selectively regulates mediator production and release in an IgE-dependent manner. To uncover the activity of Tci-gal-1, we have examined the effect of the protein on gene expression, protein production, and apoptosis in activated basophilic leukaemia RBL-2H3 cells. Rat RBL-2H3 cells were activated with anti-DNP IgE and DNP-HSA, and then treated with Tci-gal-1. Microarray analysis was used to examine gene expression. The levels of several apoptosis-related molecules and cytokines were determined using antibody arrays and ELISA. Early and late apoptosis was evaluated cytometrically. Degranulation of cells was determined by a β-hexosaminidase release assay. Treatment of activated RBL-2H3 cells with Tci-gal-1 resulted in inhibited apoptosis and decreased degranulation, although we did not detect significant changes in gene expression. The production of pro-apoptotic molecules, receptor for advanced glycation end products (RAGE) and Fas ligand (FasL), and the cytokines IL-9, IL-10, IL-13, TNF-α, and IL-2 was strongly inhibited. Tci-gal-1 modulates apoptosis, degranulation, and production of cytokines by activated RBL-2H3 cells without detectable influence on gene transcription. This parasite protein is crucial for modulation of the protective immune response and the inhibition of chronic inflammation driven by mast cell activity.

Influence of bovine pestivirus heterogeneity on serological responses to 10 different commercial vaccine formulation

Bovine Pestivirus typically involves one or more organ systems, with clinical manifestations ranging from mild to severe fatal systemic illness that lead to significant reproductive, productive, and economic losses. Vaccines face the challenge of addressing the significant variability of pestiviruses, which affects the interaction between viral antigens and the immune system’s ability to provide protection. This study aimed to evaluate the serological responses against bovine viral diarrhea virus 1 (Pestivirus A) and Pestivirus B induced by 10 commercial vaccines, including one recombinant (vaccine E), two modified live (MLV multivalent, vaccine I, and MLV monovalent, vaccine J), and seven killed vaccines (KLV, vaccines A to H). Additionally, we evaluated the cross-reactivity between Pestivirus A and B from vaccines and HoBi-like pestivirus (Pestivirus H). In Phase 1, guinea pigs were used to screen for non-MLVs. They were divided into nine groups (n=6 each) and received two doses (⅕ of bovine dose) of eight different non-MLV on Days 0 and 21. Serum samples were collected on Days 0 and 30 for serological analyse. In Phase 2, Holstein × Gir heifers (n= 45) were divided into five groups, comprising 6–9 animals. They were vaccinated either once with MLVs or twice with the top non-MLVs screened in Phase 1. Serum samples were harvested on d0 (vaccination day) and d60 (60 days after the first dose) for MLV and non-MLV. Specific antibody titers were assessed virus neutralization (VN) and transformed in log2 for statistical analysis using PROC-MIXED. Significant effects were observed for vaccine groups, time points, and their interactions concerning neutralizing antibodies against Pestivirus A and B in both Guinea pigs and heifers. The Phase 1 study revealed serological responses against Pestivirus A exclusively in non-MLV D (85.33±13.49) and E (72.00±19.26). In the bovine study, the KLD vaccine D (72.00±15.10), recombinant vaccine E (90.66±25.85), and MLV I (170.66±28.22) resulted in an average of neutralizing antibodies against Pestivirus A that exceeded the protective threshold (≥ 60). However,individual analysis of heifers showed a higher frequency of animals presenting titers of Pestivirus A Ab surpassing 32 following vaccination with MLV I and J. None of the vaccine formulations in either study elicited a protective immune response against Pestivirus B or demonstrated cross-reactivity against Pestivirus H.

Tibial cortex transverse transport surgery improves wound healing in patients with severe type 2 DFUs by activating a systemic immune response: a cross-sectional study.

Tibial cortex transverse transport (TTT) surgery has become an ideal treatment for patients with type 2 severe diabetic foot ulcerations (DFUs) while conventional treatments are ineffective. Based on our clinical practice experience, the protective immune response from TTT surgery may play a role against infections to promote wound healing in patients with DFUs. Therefore, this research aimed to systematically study the specific clinical efficacy and the mechanism of TTT surgery. Between June 2022 and September 2023, 68 patients with type 2 severe DFUs were enrolled and therapized by TTT surgery in this cross-sectional and experimental study. Major clinical outcomes including limb salvage rate and antibiotics usage rate were investigated. Ten clinical characteristics and laboratory features of glucose metabolism and kidney function were statistically analyzed. Blood samples from 6 key time points of TTT surgery were collected for label-free proteomics and clinical immune biomarker analysis. Besides, tissue samples from 3 key time points were for spatially resolved metabolomics and transcriptomics analysis, as well as applied to validate the key TTT-regulated molecules by RT-qPCR. Notably, 64.7% of patients did not use antibiotics during the entire TTT surgery. TTT surgery can achieve a high limb salvage rate of 92.6% in patients with unilateral or bilateral DFUs. Pathway analysis of a total of 252 differentially expressed proteins (DEPs) from the proteomic revealed that the immune response induced by TTT surgery at different stages was first comprehensively verified through multi-omics combined with immune biomarker analysis. The function of upward transport was activating the systemic immune response, and wound healing occurs with downward transport. The spatial metabolic characteristics of skin tissue from patients with DFUs indicated downregulated levels of stearoylcarnitine and the glycerophospholipid metabolism pathway in skin tissue from patients with severe DFUs. Finally, the expressions of PRNP (prion protein) to activate the immune response, PLCB3 (PLCB3, phospholipase C beta 3) and VE-cadherin to play roles in neovascularization, and PPDPF (pancreatic progenitor cell differentiation and proliferation factor), LAMC2 (laminin subunit gamma 2) and SPRR2G (small proline rich protein 2G) to facilitate the developmental process mainly keratinocyte differentiation were statistically significant in skin tissues through transcriptomic and RT-qPCR analysis. Tibial cortex transverse transport (TTT) surgery demonstrates favorable outcomes for patients with severe type 2 DFUs by activating a systemic immune response, contributing to anti-infection, ulcer recurrence, and the limb salvage rate for unilateral or bilateral DFUs. The specific clinical immune responses, candidate proteins, genes, and metabolic characteristics provide directions for in-depth mechanistic research on TTT surgery. Further research and public awareness are needed to optimize TTT surgery in patients with severe type 2 DFUs.

Measuring Immunoglobulin Titers Among Healthcare Workers After Hepatitis B Vaccination: A Cross-Sectional Study in Kuwait.

Introduction Hepatitis B virus (HBV) is a highly infectious disease affecting the liver, causing life-threatening acute and chronic hepatitis. It poses a significant global public health burden and is a major occupational risk for healthcare workers (HCWs) due to transmission through blood and blood products. Given their increased risk compared to the general population, vaccination is crucial in limiting the spread of HBV and protecting HCWs. This study aims to measure the anti-HBs titers of HCWs in the Farwaniyah Health District in Kuwait after completing three doses of the HBV vaccine. Methods This cross-sectional study was conducted in the Farwaniyah Health District of Kuwait between May and July 2023. We collected data from 556 participants from various departments, including physicians, nurses, and laboratory technicians, chosen through simple random sampling. Inclusion criteria included the completion of three doses of the HBV vaccine (Engerix-B recombinant vaccine, GlaxoSmithKline Biologicals, Brentford, UK). Demographic data were collected, and blood samples were tested for hepatitis B surface antigen antibody titers using fourth-generation enzyme-linked immunosorbent assay. Participants were categorized based on sex, age, specialty, and time since the last vaccine dose. The chi-square test and Fisher's exact test assessed differences in categorical variables, with a p-value of <0.05 considered statistically significant. Results The study included 556 participants, with 304 (54.7%) women and 252 (45.3%) men. Participants were assigned into two age groups: 294 (52.9%) were 18 to 40 years oldand the remainder (262) were over 40. Most participants were nursing staff (n=392; 70.5%), followed by physicians (n=110; 19.7%) and technicians (n=54; 9.7%). A high proportion (n=340; 61.2%) received their last vaccine dose within the last five years. Overall, 375 (67.4%) HCWs developed sufficient anti-HBs titers of ≥100 mIU/mLwhile 181 (32.6%) had levels below 100 mIU/mL. Age between 18 and 40 years and receiving the vaccine within the last five years were significantly associated with protective titer levels, while sex was not. Nurses had significantly higher immunity levels compared to doctors and technicians. Conclusions HCWs in the Farwaniyah area of Kuwait generally responded positively to the HBV vaccine. Younger HCWs and those who received the vaccine more recently were more likely to have a protective immune response. Nurses demonstrated higher rates of seroconversion compared to doctors and technicians. These results suggest that HBV vaccination programs should prioritize timely booster doses, especially for older HCWs and those vaccinated longago. Monitoring antibody levels is crucial to ensure ongoing protection, particularly in high-risk groups such as nurses. Implementing these measures can enhance the effectiveness of HBV vaccination programs, reduce HBV incidence among HCWs, and contribute to a safer healthcare environment. Post-vaccination testing is essential to ensure the safety of all HCWs against HBV.

Phytochemical screening and anti-inflammatory activities of different fractions from Citrullus lanatus leaves: A comprehensive study

Inflammation, a protective immune response, can contribute to maintaining homeostasis but can also cause harm when chronic or excessive. Citrullus lanatus has been suggested to possess antioxidant and anti-inflammatory activities that may aid in preventing and treating oxidative stress and inflammation. The main objective of this study was to evaluate the levels of phytochemicals, as well as the antioxidant and anti-inflammatory activities of Citrullus lanatus leaves extract. The ethyl acetate, hexane, butanol fraction and aqueous methanol extract were subjected to various standard quantitative phytochemical analysis, while the hexane fraction and aqueous methanol extract were subjected to standard in vitro anti-inflammatory assays. Spectrophotometric and gravimetric methods were used in this study. The in vitro anti-denaturation (stabilization) assay was used for detecting a wide range of antioxidant compounds. The ethyl acetate fraction had the highest flavonoid and polyphenol levels, followed by hexane, butanol, and aqueous methanol extract, respectively. Quantitative phytochemical analysis showed the levels of flavonoids, polyphenols, tannins, alkaloids and saponins present in the different fractions of C. lanatus. The human erythrocyte membrane stabilization assay showed that extracts were able to stabilize human red blood cell membrane against hypotonic-induced hemolysis in five different samples. The extract of Citrullus lanatus was found to have the highest antioxidant activity. This study has shown that the leaves of Citrullus lanatus can be used in ethnomedicine for the prevention and treatment of ailments caused by oxidative stress and inflammation-related diseases.

Evaluation of safety and immunogenicity of a genetically modified rabies virus for use as an oral vaccine in several non-target species1

Oral immunization is an alternative or supplementary approach that can significantly improve dog vaccination coverage, especially for free-roaming dogs. Safe and effective oral rabies vaccines for dogs are still being sought. In our previous studies, we generated a genetically modified rabies virus (RABV) ERA strain, rERAG333E, containing a mutation from arginine (Arg, R) to glutamic acid (Glu, E) at residue 333 of the G protein (G333E). Our previous results demonstrated that rERAG333E was safe for adult mice and dogs, and oral vaccination with rERAG333E induced a strong and long-lasting protective immune response in dogs. Here, we further investigated the safety and immunogenicity of rERAG333E in non-target species, including suckling mice, rhesus monkeys, foxes, raccoon dogs, piglets, goats, and sheep. Suckling mice studies demonstrated that the G333E mutation significantly reduced the virulence of the ERA strain. All of the suckling mice aged 10 days and above survived and showed no apparent signs of disease after intracerebral inoculation with rERAG333E. Animal studies demonstrated that rERAG333E was safe in rhesus monkeys, foxes, raccoon dogs, piglets, goats, and sheep. None of those animals inoculated orally with 10 times the intended field dose of rERAG333E showed abnormal clinical signs before and after the booster immunization with Rabvac 3, an inactivated rabies vaccine. Meanwhile, oral inoculation with rERAG333E induced strong neutralizing antibody (NA) responses to RABV in rhesus monkeys, foxes, raccoon dogs, and piglets. These results demonstrated that rERAG333E has the potential to serve as a safe oral rabies vaccine for dogs.

Commensal microbiome and gastrointestinal mucosal immunity: Harmony and conflict with our closest neighbor.

The gastrointestinal tract contains a wide range of microorganisms that have evolved alongside the immune system of the host. The intestinal mucosa maintains balance within the intestines by utilizing the mucosal immune system, which is controlled by the complex gut mucosal immune network. This review aims to comprehensively introduce current knowledge of the gut mucosal immune system, focusing on its interaction with commensal bacteria. The gut mucosal immune network includes gut-associated lymphoid tissue, mucosal immune cells, cytokines, and chemokines. The connection between microbiota and the immune system occurs through the engagement of bacterial components with pattern recognition receptors found in the intestinal epithelium and antigen-presenting cells. This interaction leads to the activation of both innate and adaptive immune responses. The interaction between the microbial community and the host is vital for maintaining the balance and health of the host's mucosal system. The gut mucosal immune network maintains a delicate equilibrium between active immunity, which defends against infections and damaging non-self antigens, and immunological tolerance, which allows for the presence of commensal microbiota and dietary antigens. This balance is crucial for the maintenance of intestinal health and homeostasis. Disturbance of gut homeostasis leads to enduring or severe gastrointestinal ailments, such as colorectal cancer and inflammatory bowel disease. Utilizing these factors can aid in the development of cutting-edge mucosal vaccines that have the ability to elicit strong protective immune responses at the primary sites of pathogen invasion.

Intranasal Vaccination with Recombinant TLR2-Active Outer Membrane Vesicles Containing Sequential M2e Epitopes Protects against Lethal Influenza a Challenge.

Influenza is a highly contagious respiratory disease, resulting in an estimated 3 to 5 million cases of severe illness annually. While most influenza vaccines are administered parenterally via injection, one shortcoming is that they do not generate a strong immune response at the site of infection, which can become important in a pandemic. Intranasal vaccines can generate both local and systemic protective immune responses, can reduce costs, and enhance ease of administration. Previous studies showed that parenterally administered outer membrane vesicles (OMVs) that carry sequences of the M2e protein (OMV-M2e) protect against influenza A/PR8 challenge in mice and ferrets. In the current study, we measured the effectiveness of the intranasal route of the OMV-M2e vaccine against the influenza A/PR8 strain in mice. We observed high anti-M2e IgG and IgA titers post-challenge in mice vaccinated intranasally with OMV-M2e. In addition, we observed a Th1/Tc1 bias in the vaccinated mice, and an increased Th17/Tc17 response, both of which correlated with survival to A/PR8 challenge and significantly lower lung viral titers. We conclude that the intranasal-route administration of the OMV-M2e vaccine is a promising approach toward generating protection against influenza A as it leads to an increased proinflammatory immune response correlating with survival to viral challenge.

Tristetraprolin mediates immune evasion of mycobacterial infection in macrophages.

Immune evasion of Mycobacterium tuberculosis (Mtb) facilitates intracellular bacterial growth. The mechanisms of immune evasion, however, are still not fully understood. In this study, we reveal that tristetraprolin (TTP), one of the best characterized RNA-binding proteins controlling the stability of targeted mRNAs, mediates innate immune evasion of mycobacteria. We found that TTP knockout mice displayed reduced bacterial burden in the early stage after Mtb aerosol challenge. Macrophages deficient in TTP also showed an inhibition in intracellular mycobacterial growth. Live mycobacteria induced TTP protein expression in macrophages, which was blocked by the mTOR inhibitor rapamycin. Rapamycin and AZD8055 specifically blocked 4EBP1 phosphorylation in infected macrophages and suppressed intracellular BCG growth. Rapamycin promoted TTP protein degradation through the ubiquitination pathway, whereas the proteasome inhibitor MG-132 blocked rapamycin function and thus stabilized TTP protein. TTP induction suppressed the expression of iNOS/TNF-α/IL-12/IL-23, and weakened protective immune responses in macrophages, whereas rapamycin enhanced the bactericidal effects through TTP inhibition. Moreover, blocking TTP binding increased the expression of TNF-α and iNOS and suppressed intracellular mycobacterial growth. Overall, our study reveals a novel role for RNA-binding protein TTP in Mtb immune evasion mechanisms and provides a potential target for host-directed therapy against tuberculosis (TB).

Mef2d potentiates type-2 immune responses and allergic lung inflammation.

Innate lymphoid cells (ILCs) and adaptive T lymphocytes promote tissue homeostasis and protective immune responses. Their production depends on the transcription factor GATA3, which is further elevated specifically in ILC2s and T helper 2 cells to drive type-2 immunity during tissue repair, allergic disorders, and anti-helminth immunity. The control of this crucial up-regulation is poorly understood. Using CRISPR screens in ILCs we identified previously unappreciated myocyte-specific enhancer factor 2d (Mef2d)-mediated regulation of GATA3-dependent type-2 lymphocyte differentiation. Mef2d-deletion from ILC2s and/or T cells specifically protected against an allergen lung challenge. Mef2d repressed Regnase-1 endonuclease expression to enhance IL-33 receptor production and IL-33 signaling and acted downstream of calcium-mediated signaling to translocate NFAT1 to the nucleus to promote type-2 cytokine-mediated immunity.

Deciphering Immune Responses to Immunization via Transcriptional Analysis: A Narrative Review of the Current Evidence towards Personalized Vaccination Strategies.

The development of vaccines has drastically reduced the mortality and morbidity of several diseases. Despite the great success of vaccines, the immunological processes involved in protective immunity are not fully understood and several issues remain to be elucidated. Recently, the advent of high-throughput technologies has enabled a more in-depth investigation of the immune system as a whole and the characterization of the interactions of numerous components of immunity. In the field of vaccinology, these tools allow for the exploration of the molecular mechanisms by which vaccines can induce protective immune responses. In this review, we aim to describe current data on transcriptional responses to vaccination, focusing on similarities and differences of vaccine-induced transcriptional responses among vaccines mostly in healthy adults, but also in high-risk populations, such as the elderly and children. Moreover, the identification of potential predictive biomarkers of vaccine immunogenicity, the effect of age on transcriptional response and future perspectives for the utilization of transcriptomics in the field of vaccinology will be discussed.

Multi-COBRA hemagglutinin formulated with cGAMP microparticles elicits protective immune responses against influenza viruses.

Influenza viruses cause severe respiratory disease, particularly in the very young and the elderly. Next-generation influenza vaccines are needed to protect against new influenza variants. This report used a promising adjuvant, cyclic GMP-AMP (cGAMP), to enhance the elicited antibodies by an improved influenza hemagglutinin candidate and protect against influenza virus infection. Overall, adding adjuvants to influenza vaccines is an effective method to improve vaccines.

Proteomics Analysis of Duck Lung Tissues in Response to Highly Pathogenic Avian Influenza Virus.

Domestic ducks (Anas platyrhynchos domesticus) are resistant to most of the highly pathogenic avian influenza virus (HPAIV) infections. In this study, we characterized the lung proteome and phosphoproteome of ducks infected with the HPAI H5N1 virus (A/duck/India/02CA10/2011/Agartala) at 12 h, 48 h, and 5 days post-infection. A total of 2082 proteins were differentially expressed and 320 phosphorylation sites mapping to 199 phosphopeptides, corresponding to 129 proteins were identified. The functional annotation of the proteome data analysis revealed the activation of the RIG-I-like receptor and Jak-STAT signaling pathways, which led to the induction of interferon-stimulated gene (ISG) expression. The pathway analysis of the phosphoproteome datasets also confirmed the activation of RIG-I, Jak-STAT signaling, NF-kappa B signaling, and MAPK signaling pathways in the lung tissues. The induction of ISG proteins (STAT1, STAT3, STAT5B, STAT6, IFIT5, and PKR) established a protective anti-viral immune response in duck lung tissue. Further, the protein-protein interaction network analysis identified proteins like AKT1, STAT3, JAK2, RAC1, STAT1, PTPN11, RPS27A, NFKB1, and MAPK1 as the main hub proteins that might play important roles in disease progression in ducks. Together, the functional annotation of the proteome and phosphoproteome datasets revealed the molecular basis of the disease progression and disease resistance mechanism in ducks infected with the HPAI H5N1 virus.

A Comprehensive Review of Hepatitis B Vaccine Nonresponse and Associated Risk Factors.

Hepatitis B virus (HBV) infection remains a significant global health concern worldwide, contributing to high rates of mortality and morbidity, including chronic hepatitis B, cirrhosis, and hepatocellular carcinoma (HCC). Universal vaccination programs have significantly reduced the rate of HBV transmission; however, a subset of individuals fail to develop a protective immune response following vaccination and are termed nonresponders. A comprehensive search strategy using the PubMed, Google Scholar, and Web of Science databases was employed to search for relevant studies using keywords including "hepatitis B vaccine", "vaccine nonresponse", "immunogenicity", "immune response to the hepatitis B vaccine", and "associated risk factors". Factors influencing the vaccine's response include demographic factors, such as age and sex, with increased nonresponse rates being observed in older adults and males. Obesity, smoking, and alcohol consumption are lifestyle factors that decrease the vaccine response. Medical conditions, including diabetes, chronic kidney and liver diseases, HIV, celiac disease, and inflammatory bowel disease, affect the vaccine response. Major histocompatibility complex (MHC) haplotypes and genetic polymorphisms linked to immune regulation are genetic factors that further influence the vaccine's effectiveness. To reduce the global burden of hepatitis B infection, it is essential to understand these factors to improve vaccine effectiveness and develop individualized vaccination strategies.

Longitudinal assessment of human antibody binding to hemagglutinin elicited by split-inactivated influenza vaccination over six consecutive seasons.

Participants between the ages of 10-86 years old were vaccinated with split-inactivated influenza vaccine (Fluzone®) in six consecutive influenza seasons from 2016-2017 to 2021-2022. Vaccine effectiveness varies from season to season as a result of both host immune responses as well as evolutionary changes in the influenza virus surface glycoproteins that provide challenges to vaccine manufacturers to produce more effective annual vaccines. Next generation influenza vaccines are in development and may provide protective immune responses against a broader number of influenza viruses and reduce the need for annual vaccination. An improved understanding how current influenza vaccines are influenced by human host immune responses in people of different ages and co-morbidities is necessary for designing the next-generation of 'universal' or broadly-protective influenza vaccines. Overall, pre-existing immune responses to previous influenza virus exposures, either by past infections or vaccinations, is a critical factor influencing host responses to seasonal influenza vaccination. Participants vaccinated in consecutive seasons had reduced serum hemagglutination-inhibition (HAI) activity against strains included in the vaccine compared to participants that had not been vaccinated in the preceding 1-2 years prior to entering this study. The magnitude and breadth of these antibody responses were also modulated by the age of the participant. Elderly participants over 65 years of age, in general, had lower pre-existing HAI titers each season prior to vaccination with lower post-vaccination titers compared to children or young adults under the age of 35. The administration of higher doses (HD) of the split-inactivated vaccine enhanced the antibody titers in the elderly. This report showcases 6 consecutive years of antibody HAI activity in human subjects receiving seasonal split-inactivated influenza vaccine.

A Computationally Optimized Broadly Reactive Hemagglutinin and Neuraminidase Vaccine Boosts Antibody-Secreting Cells and Induces a Robust Serological Response, Preventing Lung Damage in a Pre-Immune Model.

The hemagglutinin (HA) and neuraminidase (NA) surface proteins are the primary and secondary immune targets for most influenza vaccines. In this study, H2, H5, H7, N1, and N2 antigens designed by the computationally optimized broadly reactive antigen (COBRA) methodology were incorporated into an adjuvant-formulated vaccine to assess the protective efficacy and immune response against A/Hong Kong/125/2017 H7N9 virus challenge in pre-immune mice. The elicited antibodies bound to H2, H5, H7, N1, and N2 wild-type antigens; cH6/1 antigens; and cH7/3 antigens, with hemagglutinin inhibition (HAI) activity against broad panels of the H2Nx, H5Nx, and H7Nx influenza strains. Mice vaccinated with the pentavalent COBRA HA/NA vaccine showed little to no weight loss, no clinical signs of diseases, and were protected from mortality when challenged with the lethal H7N9 virus. Virus titers in the lungs of vaccinated mice were lower and cleared more rapidly than in mock-vaccinated mice. Some vaccinated mice showed no detectable lung injury or inflammation. Antibody-secreting cells were significantly increased in COBRA-vaccinated mice, with higher total Ig and H7-specific ASC. Thus, the combination of H2, H5, H7, N1, and N2 COBRA antigens presents a potential for the formulation of a universal influenza virus vaccine.

Host Functional Response to a Prototypic Orally Delivered Self-Replicating Vaccine Platform.

The development of mucosal vaccines has been limited and could be aided by a systems vaccinology approach to identify platforms and adjuvant strategies that induce protective immune responses. The induction of local immune responses by mucosal-delivered vaccines has been difficult to evaluate from peripheral samples, as systemic responses often do not correlate with the mucosal response. Here, we utilized transcriptomics in combination with Gene Set Enrichment Analysis (GSEA) to assess innate immune activation by an oral probiotic Lactobacillus acidophilus-based vaccine platform in mice. The goal was to explore the earliest immune responses elicited after oral immunization at the Peyer's patch. Twenty-four hours after oral delivery of the L. acidophilus vaccine platform, we found an abundance of L. acidophilus at Peyer's patches and detected expression of the vaccine viral proteins and adjuvants, confirming in vivo vaccine delivery. Compared to mice orally dosed with buffer or wild-type L. acidophilus, we identified enhanced responses in immune pathways related to cytokine and gene signaling, T and B cell activation, phagocytosis, and humoral responses. While more work is needed to correlate these pathways with protection from infection and/or disease, they indicate this method's potential to evaluate and aid in the iterative development of next-generation mucosal vaccines.

SKIN MICROBIOTA AND ITS INTERPLAY WITH WOUND AND BURN HEALING: IMPACT OF EPITHELIAL BIOREGENERATOR

The skin microbiota is intimately coupled with cutaneous health and disease. Interactions between commensal microbiota and the multiple cell types involved in cutaneous wound healing regulate the immune response and promote barrier restoration. This dialog between host cells and the microbiome is dysregulated in chronic wounds and burns. To investigate whether changes in composition were present in the skin microbiome of individuals at risk of developing these lesions. Colonization of the wound and burn with commensal bacteria may promote wound and burn healing by inducing antimicrobial proteins such as Perforin-2, thus stimulating a protective immune response against pathogenic bacteria. Wound and burn infection with pathogenic bacteria results in Perforin-2 suppression in both hematopoietic and nonhematopoietic cells and inhibition of healing. A new study now shows that, in most cases, the causative agents of these infections are bacteria from the patient's own skin. For this reason, authors investigated the impact of Epithelial Bioregenerator to eliminate microorganisms from the chronic wounds and burns.