Activation Of Humoral Immunity Research Articles

Spleen-Targeted mRNA Vaccine Doped with Manganese Adjuvant for Robust Anticancer Immunity In Vivo.

The successful application of mRNA vaccines in preventing and treating infectious diseases highlights their potential as therapeutic vaccines for cancer treatment. However, unlike infectious diseases, effective antitumor therapy, particularly for solid tumors, necessitates the activation of more powerful cellular and humoral immunity to achieve clinical efficacy. Here, we report a spleen-targeted mRNA vaccine (Mn@mRNA-LNP) designed to deliver tumor antigen-encoding mRNA and manganese adjuvant (Mn2+) simultaneously to dendritic cells (DCs) in the spleen. This delivery system promotes DC maturation and surface antigen presentation and stimulates the production of cytotoxic T cells. Additionally, Mn2+ codelivered in the system serves as a safe and effective immune adjuvant, activating the stimulator of interferon genes (STING) signaling pathway and promoting the secretion of type I interferon, further enhancing the antigen-specific T cell responses. Mn@mRNA-LNP effectively inhibits tumor progression in established melanoma and colon tumor models as well as in a model of tumor recurrence after resection. Notably, the combination of Mn@mRNA-LNP with immune checkpoint inhibitors further enhances complete tumor suppression and prolonged the overall survival in mice. Overall, this "All-in-One" mRNA vaccine significantly boosts antitumor immunity responses by improving spleen targeting and immune activation, providing an attractive strategy for the future clinical translation of therapeutic mRNA vaccines.

Pathogenic relevance of antibodies against desmoglein3 inpatients with oral lichen planus.

Oral lichen planus (OLP) is a Tcell driven disorder that significantly impairs patients' quality of life. Previous reports suggest that both cellular and humoral activities against desmoglein (dsg) 1 and 3 may be involved in OLP pathogenesis. Here, we aim to analyze the frequency of occurrence and pathological significance of anti-dsg antibodies in a large cohort of OLP patients. OLP patients were screened for anti-dsg antibodies by enzyme-linked immunosorbent assay in three tertiary referral centers. OLP sera with anti-dsg antibodies were further analyzed by Western blot and dispase-based keratinocyte dissociation assay (DDA) to identify the targeted dsg ectodomains and to assess their pathogenicity. Of 151-screened individuals with OLP, only four patients (2.6%) with erosive OLP showed serum IgG against dsg1/3. Western blot analysis with recombinant dsg3 ectodomains revealed preferential recognition of the extracellular domain 5. By DDA with spontaneously immortalized human keratinocytes, none of the sera from these four patients induced acantholysis. Activation of humoral immunity occurs prevalently in patients with erosive OLP, probably due to epitope spreading. OLP serum antibodies are unable to induce loss of intercellular adhesion in vitro, strongly suggesting that they are not disease causing but rather an epiphenomenon.

Novel SARS-COV2 poly epitope phage-based candidate vaccine and its immunogenicity

Background and purpose: The global emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has prompted widespread concern. Bacteriophages have recently gained attention as a cost-effective and stable alternative for vaccine development due to their adjuvant properties. This study aimed to design and validate a poly epitope composed of viral proteins. Experimental approach: SARS-CoV-2 proteins (spike, nucleocapsid, membrane, envelope, papain-like protease, and RNA-dependent RNA polymerase) were selected for analysis. Immunoinformatic methods were employed to predict B and T cell epitopes, assessing their antigenicity, allergenicity, and toxicity. Epitopes meeting criteria for high antigenicity, non-allergenicity, and non-toxicity were linked to form poly epitopes. These sequences were synthesized and cloned into pHEN4 plasmids to generate Poly1 and Poly2 phagemid vectors. Recombinant Poly1 and Poly2 phages were produced by transforming M13ΔIII plasmids and phagemid vectors into E. coli TG1. Female Balb/c mice were immunized with a cocktail of Poly1 and Poly2 phages, and their serum was collected for ELISA testing. Interferon-gamma (IFN-γ) testing was performed on spleen-derived lymphocytes to evaluate immune system activation. Findings/Results: Recombinant Poly1 and Poly2 phages were produced, and their titer was determined as 1013 PFU/mL. Efficient humoral immune responses and cellular immunity activation in mice were achieved following phage administration. Conclusion and implication: Poly epitopes displayed on phages exhibit adjuvant properties, enhancing humoral and cellular immunity in mice. This suggests that phages could serve as adjuvants to bolster immunity against SARS-Cov-2. Recombinant phages could be applied as effective candidates for injectable and oral vaccine development strategies.

Intra‐lymph node crosslinking of antigen‐bearing polymers enhances humoral immunity and dendritic cell activation

AbstractLymph node (LN)‐resident dendritic cells (DCs) are a promising target for vaccination given their professional antigen‐presenting capabilities and proximity to a high concentration of immune cells. Direct intra‐LN injection has been shown to greatly enhance the immune response to vaccine antigens compared to traditional intramuscular injection, but it is infeasible to implement clinically in a vaccination campaign context. Employing the passive lymphatic flow of antigens to target LNs has been shown to increase total antigen uptake by DCs more than inflammatory adjuvants, which recruit peripheral DCs. Herein, we describe a novel vaccination platform in which two complementary multi‐arm poly(ethylene glycol) (PEG) polymers—one covalently bound to the model antigen ovalbumin (OVA)—are injected subcutaneously into two distinct sites. These materials then drain to the same LN through different lymphatic vessels and, upon meeting in the LN, rapidly crosslink. This system improves OVA delivery to, and residence time within, the draining LN compared to all control groups. The crosslinking of the two PEG components also improves humoral immunity without the need for any pathogen‐mimicking adjuvants. Further, we observed a significant increase in non‐B/T lymphocytes in LNs cross‐presenting the OVA peptide SIINFEKL on MHC I over a dose‐matched control containing alum, the most common clinical adjuvant, as well as an increase in DC activation in the LN. These data suggest that this platform can be used to deliver antigens to LN‐resident immune cells to produce a stronger humoral and cellular immune response over materials‐matched controls without the use of traditional adjuvants.

Application of Proteomics and Machine Learning Methods to Study the Pathogenesis of Diabetic Nephropathy and Screen Urinary Biomarkers.

Diabetic nephropathy (DN) has become the main cause of end-stage renal disease worldwide, causing significant health problems. Early diagnosis of the disease is quite inadequate. To screen urine biomarkers of DN and explore its potential mechanism, this study collected urine from 87 patients with type 2 diabetes mellitus (which will be classified into normal albuminuria, microalbuminuria, and macroalbuminuria groups) and 38 healthy subjects. Twelve individuals from each group were then randomly selected as the screening cohort for proteomics analysis and the rest as the validation cohort. The results showed that humoral immune response, complement activation, complement and coagulation cascades, renin-angiotensin system, and cell adhesion molecules were closely related to the progression of DN. Five overlapping proteins (KLK1, CSPG4, PLAU, SERPINA3, and ALB) were identified as potential biomarkers by machine learning methods. Among them, KLK1 and CSPG4 were positively correlated with the urinary albumin to creatinine ratio (UACR), and SERPINA3 was negatively correlated with the UACR, which were validated by enzyme-linked immunosorbent assay (ELISA). This study provides new insights into disease mechanisms and biomarkers for early diagnosis of DN.

Adaptive immune response in women from the Russian Arctic region after COVID-19 infection

BACKGROUND: The Arctic region of Russia is characterized by disproportionately high rates of morbidity and mortality from COVID-19 during the pandemic. The harsh climatic and environmental conditions in this area impede the development of self-regulation processes resulting in activation and strain of both cellular and humoral immunity. This leads to a depletion of the body’s reserve capacities. At present, there is lack of research examining how individuals who have recovered from COVID-19 are affected by the extreme conditions of Arctic Russia. AIM: To study the ratio of immunocompetent cells involved in the adaptive immune response following COVID-19 infection. MATERIAL AND METHODS: A total of 29 women aged 20 – 40 years were examined in Arkhangelsk as part of a comprehensive immunological study. This study involved assessment of the number of leukocytes, lymphocytes, and their phenotypes (CD5+, CD8+, CD10+, CD95+), as well as determination of phagocytic activity and phagocytic number. RESULTS: The cellular adaptive immune response in observed individuals 6 months after experiencing moderate COVID-19 disease was characterized by a very low concentration of T cells (CD5+) in all cases, CD10+ lymphocytes (44.83%) alongside with a high concentration of cytotoxic lymphocytes (CD8+) in 48.27% of individuals and lymphocytes with receptors for apoptosis (CD95+) in 51.72%, with relatively high phagocytic activity ranging from 90 to 100%. A correlation was found in 11.29% of women between the low content of CD10+ and CD95+ cells with the activity of phagocytosis. In 40% of women with high phagocytic activity, the concentrations of cytotoxic cells (CD8+) were found to be at a minimum level. CONCLUSIONS: Women with high phagocytic activity were found to have the lowest concentrations of cytotoxic cells, suggesting a potentially positive prognosis for reducing the risk of complications. This indicates that cellular immunity may play a role in determining the severity of COVID-19 infection in individuals with high phagocytic activity.

Intestinal microflora promotes Th2-mediated immunity through NLRP3 in damp and heat environments.

With the worsening of the greenhouse effect, the correlation between the damp-heat environment (DH) and the incidence of various diseases has gained increasing attention. Previous studies have demonstrated that DH can lead to intestinal disorders, enteritis, and an up-regulation of NOD-like receptor protein 3 (NLRP3). However, the mechanism of NLRP3 in this process remains unclear. We established a DH animal model to observe the impact of a high temperature and humidity environment on the mice. We sequenced the 16S rRNA of mouse feces, and the RNA transcriptome of intestinal tissue, as well as the levels of cytokines including interferon (IFN)-γ and interleukin (IL)-4 in serum. Our results indicate that the intestinal macrophage infiltration and the expression of inflammatory genes were increased in mice challenged with DH for 14 days, while the M2 macrophages were decreased in Nlrp3 -/- mice. The alpha diversity of intestinal bacteria in Nlrp3 -/- mice was significantly higher than that in control mice, including an up-regulation of the Firmicutes/Bacteroidetes ratio. Transcriptomic analysis revealed 307 differentially expressed genes were decreased in Nlrp3 -/- mice compared with control mice, which was related to humoral immune response, complement activation, phagocytic recognition, malaria and inflammatory bowel disease. The ratio of IFN-γ/IL-4 was decreased in control mice but increased in Nlrp3 -/- mice. Our study found that the inflammation induced by DH promotes Th2-mediated immunity via NLRP3, which is closely related to the disruption of intestinal flora.

Immune system parameters in patients with chronic opistorchiasis based on genetic polymorphism associated with carbohydrate and lipid metabolism disorders

A study assessing differences in the immunopathogenesis of chronic opisthorchiasis with or without genetic polymorphisms in patients associated with predisposition to type II diabetes mellitus and lipid metabolism disorders was carried out. Venous blood samples from 89 patients were collected to analyze immunological parameters and genetic polymorphisms by using pyrosequencing. In the presence of mutations affecting regulation of carbohydrate metabolism, patients with opisthorchiasis had less pronouncedly increased phagocytic activity, a lower monocyte count, higher total T-lymphocyte count, lower T-cytotoxic cell and B-lymphocyte counts, lower IgA, IgG but higher IgM concentration. This indicates a moderately compromised nonspecific resistance, imbalanced effector T- and B-immunity, but in most cases (PPARG, TCF7L2 rs12255372, CDKAL1, CDKN2A/2B, SLC30A8) aggravated humoral immune reaction to invasion particularly revealed by lower B-lymphocyte count. The presence of polymorphisms that alter lipid metabolism regulation bidirectionally affects the parameters of immune response. An increased B-lymphocyte count and other indicators of humoral immune activation to invasion, which are detected in groups with mutations in the APOE (rs429358), PCSK9, ABCA1, APOC3 rs2854117 genes, can contribute to a more effective response to sustained antigenic stimulation. Changes in the T-lymphocytes subpopulations, characteristic of opisthorchiasis invasion, are aggravated in the presence of mutations in the PCSK9, ABCA1, and APOC3 rs2854117 genes. Mutations in the genes APOC3 rs5128, LPL rs268 activate patients’ nonspecific resistance, although this effect may also be associated with exhaustion of neutrophil bactericidal reserve. In general, minor alleles of the APOE (rs429358), APOC3 rs2854117, LPL rs268, LPL rs328, PON1 rs662 genes can be considered “protective” for the immunopathogenesis of chronic opisthorchiasis. Thus, patients with chronic opisthorchiasis with different genotypes predisposing to carbohydrate and lipid metabolism disorders had significant differences in immune system parameters, which can also affect the disease course. Mutations in different loci of the PCSK9, ABCA1, APOE, APOC3, and PON1 genes have opposite effects on the analyzed immune parameters. In the presence of mutations in other genes (PPARG, TCF7L2 rs12255372, CDKAL1, CDKN2A/2B, SLC30A8, LPL), opisthorchiasis invasion leads to more pronounced alterations in immune response; mutations in the lipoprotein lipase gene may have some “protective” immune-related effect in opisthorchiasis. The effect of all studied genetic polymorphisms associated with a predisposition to developing type II diabetes mellitus was predominantly negative.

Analysis of Humoral Immunity SARS-CoV-2 Infection Model with ACE2 Receptor and Latent Phase

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is RNA virus which causes the coronavirus disease 2019 (COVID-19). SARS-CoV-2 infects the epithelial (target) cells by binding its spike protein, S, to the Angiotensin-Converting Enzyme 2 (ACE2) receptor on the surface of epithelial cells. ACE2 is an essential mediating factor in the SARS-CoV-2 infection pathway. In this study, we build a mathematical model for characterizing the dynamics of SARS-CoV-2 within the host while taking into account the impact of humoral immunity and the function of the ACE2 receptor. We incorporate the cells that are latently infected into the model. We consider three distributed delays: (i) delay in development of latently infected epithelial cells, (ii) delay in the latently infected epithelium cells’ activation, and (iii) delay in the maturation of recently released SARS-CoV-2 virions. We first address the fundamental properties of the delayed system, then find all possible equilibria. We demonstrate the existence and stability of the equilibria on the basis of two threshold parameters, namely basic reproduction number (ℜ₀) and humoral immune activation number (ℜ1). By building appropriate Lyapunov functions and applying LaSalle’s invariance principle, we prove the global asymptotic stability for all equilibria. We do numerical simulations to demonstrate the theoretical conclusions. We do sensitivity analysis and determine the most vulnerable parameters. Discussion is had on how the dynamics of the SARS-CoV-2 are affected by ACE2 receptors, humoral immunity, latent phase and time delays. It is shown that vigorous activation of humoral immunity can suppress viral multiplication. We found that, ℜ₀ is influenced by the rates of ACE2 receptor growth and degradation, and this may offer valuable guidance for the creation of potential receptor-targeted vaccinations and medications. Further, it is shown that, increasing time delays can effectively decrease ℜ₀ and then inhibit the SARS-CoV-2 replication. Finally, we showed that, excluding the latently infected cells in the model would result in an overestimation of ℜ₀. Our findings may be useful in understanding the dynamics of SARS-CoV-2 infection in the host as well as in the development of novel therapies.

Biofunctional lipid nanoparticles for precision treatment and prophylaxis of bacterial infections.

The lack of bacterial-targeting function in antibiotics and their prophylactic usage have caused overuse of antibiotics, which lead to antibiotic resistance and inevitable long-term toxicity. To overcome these issues, we develop neutrophil-bacterial hybrid cell membrane vesicle (HMV)-coated biofunctional lipid nanoparticles (LNP@HMVs), which are designed to transport antibiotics specifically to bacterial cells at the infection site for the effective treatment and prophylaxis of bacterial infection. The dual targeting ability of HMVs to inflammatory vascular endothelial cells and homologous Gram-negative bacterial cells results in targeted accumulation of LNP@HMVs in the site of infections. LNP@HMVs loaded with the antibiotic norfloxacin not only exhibit enhanced activity against planktonic bacteria and bacterial biofilms in vitro but also achieve potent therapeutic efficacy in treating both systemic infection and lung infection. Furthermore, LNP@HMVs trigger the activation of specific humoral and cellular immunity to prevent bacterial infection. Together, LNP@HMVs provide a promising strategy to effectively treat and prevent bacterial infection.

XX sex chromosome complement modulates immune responses to heat-killed Streptococcus pneumoniae immunization in a microbiome-dependent manner.

Differences in male vs. female immune responses are well-documented and have significant clinical implications. While the immunomodulatory effects of sex hormones are well established, the contributions of sex chromosome complement (XX vs. XY) and gut microbiome diversity on immune sexual dimorphisms have only recently become appreciated. Here we investigate the individual and collaborative influences of sex chromosome complements and gut microbiota on humoral immune activation. Male and female Four Core Genotype (FCG) mice were immunized with heat-killed Streptococcus pneumoniae (HKSP). Humoral immune responses were assessed, and X-linked immune-related gene expression was evaluated to explain the identified XX-dependent phenotype. The functional role of Kdm6a, an X-linked epigenetic regulatory gene of interest, was evaluated ex vivo using mitogen stimulation of B cells. Additional influences of the gut microbiome on sex chromosome-dependent B cell activation was also evaluated by antibiotically depleting gut microbiota prior to HKSP immunization. Reconstitution of the depleted microbiome with short-chain fatty acid (SCFA)-producing bacteria tested the impact of SCFAs on XX-dependent immune activation. XX mice exhibited higher HKSP-specific IgM-secreting B cells and plasma cell frequencies than XY mice, regardless of gonadal sex. Although Kdm6a was identified as an X-linked gene overexpressed in XX B cells, inhibition of its enzymatic activity did not affect mitogen-induced plasma cell differentiation or antibody production in a sex chromosome-dependent manner ex vivo. Enhanced humoral responses in XX vs. XY immunized FCG mice were eliminated after microbiome depletion, indicating that the microbiome contributes to the identified XX-dependent immune enhancement. Reconstituting microbiota-depleted mice with select SCFA-producing bacteria enhanced fecal SCFA concentrations and increased humoral responses in XX, but not XY, FCG mice. However, exposure to the SCFA propionate alone did not enhance mitogenic B cell stimulation in ex vivo studies. FCG mice have been used to assess sex hormone and sex chromosome complement influences on various sexually dimorphic traits. The current study indicates that the gut microbiome impacts humoral responses in an XX-dependent manner, suggesting that the collaborative influence of gut bacteria and other sex-specific factors should be considered when interpreting data aimed at delineating the mechanisms that promote sexual dimorphism.

Self-assembled ferritin-based nanoparticles elicit a robust broad-spectrum protective immune response against SARS-CoV-2 variants

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and its variants has resulted in global economic losses and posed a threat to human health. The pandemic highlights the urgent need for an efficient, easily producible, and broad-spectrum vaccine. Here, we present a potentially universal strategy for the rapid and general design of vaccines, focusing on the design and testing of omicron BA.5 RBD-conjugated self-assembling ferritin nanoparticles (NPs). The covalent bonding of RBD-Fc to protein A-ferritin was easily accomplished through incubation, resulting in fully multivalent RBD-conjugated NPs that exhibited high structural uniformity, stability, and efficient assembly. The ferritin nanoparticle vaccine synergistically stimulated the innate immune response, Tfh-GCB-plasma cell-mediated activation of humoral immunity and IFN-γ-driven cellular immunity. This nanoparticle vaccine induced a high level of cross-neutralizing responses and protected golden hamsters challenged with multiple mutant strains from infection-induced clinical disease, providing a promising strategy for broad-spectrum vaccine development for SARS-CoV-2 prophylaxis. In conclusion, the nanoparticle conjugation platform holds promise for its potential universality and competitive immunization efficacy and is expected to facilitate the rapid manufacturing and broad application of next-generation vaccines.

Delivery of a Hepatitis C Virus Vaccine Encoding NS3 Linked to the MHC Class II Chaperone Protein Invariant Chain Using Bacterial Ghosts.

Efficient delivery of a DNA plasmid into antigen-presenting cells (APCs) is a potential strategy to enhance the immune responses of DNA vaccines. The bacterial ghost (BG) is a potent DNA vaccine delivery system that targets APCs. In the present work, we describe a new strategy of using E. coli BGs as carriers for an Ii-linked Hepatitis C Virus (HCV) NS3 DNA vaccine that improved both the transgene expression level and the antigen-presentation level in APCs. BGs were prepared from DH5α cells, characterized via electron microscopy and loaded with the DNA vaccine. The high transfection efficiency mediated using BGs was first evaluated in vitro, and then, the immune protective effect of the BG-Ii-NS3 vaccine was determined in vivo. It was found that the antibody titer in the sera of BG-Ii-NS3-challenged mice was higher than that of Ii-NS3-treated mice, indicating that the BGs enhanced the humoral immune activity of Ii-NS3. The cellular immune protective effect of the BG-Ii-NS3 vaccine was determined using long-term HCV NS3 expression in a mouse model in which luciferase was used as a reporter for HCV NS3 expression. Our results showed that the luciferase activity in BG-Ii-NS3-treated mice was significantly reduced compared with that in Ii-NS3-treated mice. The CTL assay results demonstrated that BG-Ii-NS3 induced a greater NS3-specific T-cell response than did Ii-NS3. In summary, our study demonstrated that BGs enhanced both the humoral and cellular immune response to the Ii-NS3 DNA vaccine and improved its immune protection against HCV infection.

ОСОБЕННОСТИ ИММУННОГО СТАТУСА У БОЛЬНЫХ ГЛОМЕРУЛОНЕФРИТАМИ С РЕФРАКТЕРНЫМ НЕФРОТИЧЕСКИМ СИНДРОМОМ

Abstract. Introduction. Research in the issues related to glomerulonephritis with nephrotic syndrome is an important problem of modern medicine due to their prevalence among the global population and mainly in the younger age group, with a significant proportion of patients with refractory nephrotic syndrome (frequent relapses, persistent course). Currently, there are no ways to predict the development of glomerulonephrites with refractory nephrotic syndrome. Due to the immunological nature of glomerulonephrites, it seems advisable to search for predictors of refractory nephrotic syndrome among the indicators characterizing the patient’s immune status. Aim of the study was to study the characteristic features of the immune status and their prognostic value in glomerulonephritis with refractory nephrotic syndrome. Materials and Methods. We examined 136 glomerulonephritis patients with active nephrotic syndrome, hospitalized in the nephrology department in 2015-2021. Along with conventional examinations, humoral and T-cell immunity indicators were tested in the patients. The end point of the study was in 2022 where the the clinical course of the disease was assessed in patients, and patients with nephrotic syndrome who showed refractory to steroid therapy were placed into one group, while those with non–refractory nephrotic syndrome were placed into another one. Within the selected groups of patients, we performed the comparative study of demographic, clinical and laboratory parameters, the indicators of humoral and T-cell immunity, and the ROC analysis of indicators correlating with the nephrotic syndrome recurrence frequency. Results and Discussion. In the group of patients with a refractory course of the disease, an increase was detected in the number of T helper phenotype cells and of the activated T cells carrying activation markers, HLA-DR and CD38, on their surfaces. At the same time, the relative content of regulatory T cells (Treg) among T helper cells decreased. The B system was characterized by an increase in the number of B lymphocytes, an increase in the levels of circulating immune complexes and IgM, and a decrease in IgG levels. The changes detected in the parameters of humoral and T-cell immunity may be essential to the development of refractory nephrotic syndrome. In the refractory nephrotic syndrome pathogenesis, the most important is the decrease in the number of Tregs, which correlated most closely with the nephrotic syndrome recurrence frequency. Conclusions. An association was found between refractory nephrotic syndrome and the pronounced activation of humoral immunity, and a significant imbalance was detected between various immunoregulatory and activated T-lymphocyte subpopulations. The Treg content in the blood can be a prognostic indicator: Treg content values of under 1.9% indicate a high probability of developing refractory nephrotic syndrome.

Global properties of delayed models for SARS-CoV-2 infection mediated by ACE2 receptor with humoral immunity

<abstract><p>The coronavirus disease 2019 (COVID-19) is caused by a new coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 infects the epithelial (target) cells by binding its spike protein, S, to the angiotensin-converting enzyme 2 (ACE2) receptor on the surface of epithelial cells. During the process of SARS-CoV-2 infection, ACE2 plays an important mediating role. In this work, we develop two models which describe the within-host dynamics of SARS-CoV-2 under the effect of humoral immunity, and considering the role of the ACE2 receptor. We consider two discrete (or distributed) delays: (ⅰ) Delay in the SARS-CoV-2 infection of epithelial cells, and (ⅱ) delay in the maturation of recently released SARS-CoV-2 virions. Five populations are considered in the models: Uninfected epithelial cells, infected cells, SARS-CoV-2 particles, ACE2 receptors and antibodies. We first address the fundamental characteristics of the delayed systems, then find all possible equilibria. On the basis of two threshold parameters, namely the basic reproduction number, $ \Re_{0} $, and humoral immunity activation number, $ \Re_{1} $, we prove the existence and stability of the equilibria. We establish the global asymptotic stability for all equilibria by constructing suitable Lyapunov functions and using LaSalle's invariance principle. To illustrate the theoretical results, we perform numerical simulations. We perform sensitivity analysis and identify the most sensitive parameters. The respective influences of humoral immunity, time delays and ACE2 receptors on the SARS-CoV-2 dynamics are discussed. It is shown that strong stimulation of humoral immunity may prevent the progression of COVID-19. It is also found that increasing time delays can effectively decrease $ \Re_{0} $ and then inhibit the SARS-CoV-2 replication. Moreover, it is shown that $ \Re_{0} $ is affected by the proliferation and degradation rates of ACE2 receptors, and this may provide worthy input for the development of possible receptor-targeted vaccines and drugs. Our findings may thus be helpful for developing new drugs, as well as for comprehending the dynamics of SARS-CoV-2 infection inside the host.</p></abstract>

Preparation of viromimetic rod-like nanoparticle vaccines (RLNVax) and study of their humoral immune activation efficacy.

Virus-like nanoparticle vaccines can efficiently activate the humoral immune response by cross-linking B cell receptors with their surface multivalent antigen arrays. This structurally dependent mechanism makes it crucial to regulate and optimize structural parameters to enhance the efficacy of nanoparticle vaccines. In this study, we prepared nanoparticle vaccines with different aspect ratios by chemically modifying antigen proteins onto the surfaces of poly(amino acid) nanoparticles of various shapes (spherical, ellipsoidal, and rod-like). This allowed us to investigate the impact of structural anisotropy on the humoral immune activation efficacy of nanoparticle vaccines. Furthermore, the end-group molecules of poly(amino acid) materials possess aggregation-induced emission (AIE) properties, which facilitate monitoring the dynamics of nano-assemblies within the body. Results showed that rod-like nanoparticle vaccines (RLNVax) with a higher aspect ratio (AR = 5) exhibited greater lymph node draining efficiency and could elicit more effective B cell activation compared to conventional isotropic spherical nanoparticle vaccines. In a murine subcutaneous immunization model using ovalbumin (OVA) as a model antigen, RLNVax elicited antigen-specific antibody titers that were about 64 times and 4.6 times higher than those induced by free antigen proteins and spherical nanoparticle vaccines, respectively. Additionally, when combined with an aluminum adjuvant, antibody titers elicited by RLNVax were further enhanced by 4-fold. These findings indicate that the anisotropic rod-like structure is advantageous for improving the humoral immune activation efficacy of nanoparticle vaccines, providing significant insights for the design and optimization of next-generation nanoparticle vaccines.

HUMORAL IMMUNITY IN PATIENTS WITH MULTIPLE SCLEROSIS

Introduction. More than 1 million people in the world suffer from multiple sclerosis (MS). The etiology of MS remains not fully understood. The main role in the pathogenesis of MS belongs to the combination of chronic inflammation and neurodegenerative processes, in the genesis of which autoimmune processes play a significant role. Progress in studying the mechanisms of the pathological process of demyelinating diseases has been achieved mainly thanks to immunological research. One of the manifestations of activation of humoral immunity in MS is increased synthesis of immunoglobulins in brain tissue and cerebrospinal fluid
 The aim of the study. To study the state of humoral immunity in multiple sclerosis patients with different types of disease course
 Research methods. 68 patients with a verified diagnosis of multiple sclerosis (MS) based on the MacDonald et al criteria aged 19 to 65 years (37 women, 29 men) were examined. The primary progressive type of the course was established in 19 patients, the secondary-progressive - in 3, the remitting-relapsing type of the course - in 26 patients. The control group consisted of 80 practically healthy male volunteers aged 25-45 years.
 The concentration of immunoglobulins A, G, M in blood serum was determined by the Mancini method (1965). The content of circulating immune complexes (CIC) in blood serum was determined by the method of precipitation in polyethylene glycol.
 Results and discussion. The highest content of Ig A was observed in the group of patients with primary progressive form of MS, which was 3.7 times higher than normal values and 1.2 times higher than in the general group of MS patients. In the group of patients with the secondary progressive form of MS, the content of Ig A was 3.1 times higher than in the control group and 1.2 times lower than in the group with the primary progressive form. In the group of patients with relapsing-remitting form of MS, there was an increase in the level of Ig A three times relative to the normal indicator, and a decrease (by 1.2 times) relative to the level in the group with a primary progressive form of MS.
 The content of Ig M in the blood serum of patients with MS exceeded the norm by 5 times. In the group with the primary progressive form of MS, the level of Ig M was 3.5 times higher than the level in the control group and 1.5 times lower than the level in the group of patients with MS. In patients with secondary progressive form of MS, the content of Ig M was 2.6 times higher than the norm, but 1.3 times lower than the level in the group with primary progressive form of MS and 1.9 times lower than in the group of patients with MS. In patients with the relapsing-remitting form of MS, the level of Ig M was: 4.6 times higher than the level in the control group and 1.7 times higher than the content in patients with the secondary-progressive form of MS, and also 1.3 times higher, than in the group with the primary progressive form.
 In all groups of patients with MS with different types of the course of the disease, the most pronounced increase in the level of Ig G was noted.
 The highest level of CIC was recorded in the general group of patients with MS and in the group with secondary progressive form of MS.
 Conclusions. An imbalance of the humoral link of immunity was observed in patients with multiple sclerosis. A probable increase in the concentration of Ig A in the blood serum of patients with multiple sclerosis indicates the presence of infection of the mucous membranes, which is especially pronounced in patients with the primary progressive form of multiple sclerosis. A significant increase in the content of Ig G in the blood serum of patients with multiple sclerosis indicates a chronic course of the process, which is especially evident in the relapsing-relapsing form of multiple sclerosis. An increased concentration of IgM in the blood serum of patients with multiple sclerosis may indicate an exacerbation of the course of chronic inflammation, especially in the case of relapsing-remitting multiple sclerosis. The detected fluctuations of the average content of CIC in the blood serum of patients with multiple sclerosis did not go beyond the physiological norm.

ОЦЕНКА ИММУНОМОДУЛИРУЮЩЕЙ АКТИВНОСТИ СУХОГО ЭКСТРАКТА ТРАВЫ ТОПИНАМБУРА

. The purpose of the study was to evaluate the immunomodulatory properties of the dry extract of Jerusalem artichoke herb in terms of weight (thymus, spleen), number of cells (thymus, spleen, bone marrow) of the immune system organs, indicators of cellular and humoral immunity in mice on a model of experimental immunodeficiency induced by the cytostatic methotrexate. Materials and methods. The study of the immunomodulatory activity of the dry extract of Jerusalem artichoke herb was evaluated by the ability to restore the mass (thymus, spleen), the number of cells (thymus, spleen, bone marrow) of the immune system organs, indicators of cellular, humoral immunity and phagocytic activity of peritoneal macrophages of outbred mice under conditions of immunosuppression induced by methotrexate, to the level of intact mice, in vivo. Results. Analysis of the effect of the dry extract of Jerusalem artichoke herb in in vivo systems found that the dry extract of the herb Helianthus tuberosum L. had no effect on the mass (thymus, spleen) and the number of cells (thymus, spleen, bone marrow) of the immune system organs, the severity of the delayed-type hypersensitivity reaction, antibody production, phagocytic activity of peritoneal macrophages of intact mice and restored these parameters of the immune system in animals treated with the cytostatic methotrexate to the level of intact animals, which was comparable to the effect of the reference drug "Immunal". Conclusion. The dry extract of Jerusalem artichoke herb can be considered as a promising agent that restores the parameters of cellular, humoral immunity, the phagocytic activity of peritoneal macrophages and the cellular composition of the immune system under conditions of immunosuppression induced by methotrexate, to the level of intact animals, the effectiveness of which is comparable to the effect of the comparator drug "Immunal

THE CONTENT OF SECRETORY IMMUNOGLOBULIN A IN BREAST MILK OF PATIENTS WITH LACTATIONAL MASTITIS

Introduction. The protective function of breast milk is provided by a number of specific and non-specific anti-infective factors: secretory immunoglobulin A, immunoglobulins A, G, M, E, cellular elements (neutrophils, lymphocytes, macrophages), cytokines, lactoferrin, lysozyme, oligosaccharides, bifido- and lactobacteria, antioxidants and.
 The main class of human milk immunoglobulins is secretory immunoglobulin A (sIgA), which protects the surfaces of mucous membranes from the penetration of microorganisms, neutralizes toxins and localizes viruses, and stimulates phagocytosis. Currently, information on the local level of secretory immunoglobulin A in the development of the inflammatory process in the mammary gland is not numerous and requires research.
 The aim of the study. To assess the content of secretory IgA in breast milk of patients with lactational mastitis.
 Research metods. The study dealt with breast milk of 97 women aged 18 to 36 (average age: 26±5 years old). The standard indicators of the secretory immunoglobulin A contents in 30 practically healthy lactating women of the same age – the control group – were the issue of the analyses. The first group included 30 women with lactostasis, the second group consisted of 37 women with lactational mastitis. The content of secretory immunoglobulin A was determined by enzyme immunoassay using an automatic STAT FAX 303 plus analyzer.
 Results and discussion. The concentration of sIgA in breast milk with lactostasis is on average 0.72±0.04 mg/ml, which is 3 times higher than the control indicator (0.24±0.02 mg/ml; p<0.05). During the development of lactational mastitis, the level of sIgA is 0.75±0.05 mg/ml, which exceeds the control values by 3.1 times (р<0.05). The content of sIgA in the breast milk of women with lactostasis does not differ from the level of this immunoglobulin in patients with lactational mastitis. A high concentration of sIgA indicates the activation of immune protection on mucous membranes.
 Conclusions. Increased production of secretory immunoglobulin A in breast milk was found in experimental groups compared to practically healthy women, which indicates activation of local humoral immunity as a reaction to infection.

Immunomodulatory effects of hydrolyzed Debaryomyces hansenii in Atlantic salmon (Salmo salar L): From the in vitro model to a natural pathogen challenge after seawater transfer

Non-Saccharomyces yeast such as Debaryomyces hansenii or its cell wall-components are emerging candidates for novel functional aquafeeds, as they contain several microbe-associated molecular patterns (MAMPs) that can activate and modulate the host's physiological responses, thereby improving fish health and welfare. In this study, we combined in vitro work using SHK-1 cell line and primary cultures of head kidney leukocytes (HKL) from Atlantic salmon (HKL), with an in vivo trial in which two groups of Atlantic salmon were fed 0.1% hydrolyzed D. hansenii (LAN6) in freshwater (7 weeks) and seawater (6 weeks). In vitro results by ELISA showed that after induction with LAN6, SHK-1 cells increased the levels of TNFα and iNOS (at 6 h post-induction), while HKL increased TNFα (6 h post-induction) and IL-10 (24 h post-induction), and reduced TNFα levels at 24 h post-induction. In addition, during an early natural pathogen challenge in the seawater stage (week 5), an increase in specific plasma immunoglobulins against Moritella viscosa, along with an upregulation in pathways associated with humoral immunity and complement activation in the liver was detected in vaccinated fish fed LAN6 (Group A). These data suggest that LAN6 was able to modulate the immune response of Atlantic salmon making it a promising functional feed additive for aquafeeds to achieve a more resilient farmed salmon.