Spleen Cell Cultures Research Articles

Evaluation of the immunomodulatory activity of probiotics mixture and sulfasalazine against acetic acid-induced colitis in a murine model.

Currently, the use of probiotics to treat inflammatory bowel diseases (IBD) is widely accepted because of their gut microbiota modulation capabilities and anti-inflammatory potential. The aim of this study is to examine the immunomodulatory outcomes of probiotics and sulfasalazine in the acetic acid-induced colitis murine model. The animals were randomly assigned to one of the seven groups. Following the induction of colitis, Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12, and sulfasalazine (SASP) were orally administered for 10 days. Subsequently, the in vitro anti-inflammatory effect on TNF-α and IL-10 in the supernatants of cultured spleen cells was assessed via ELISAs. Relative mRNA expression of ZO-1, MLCK, iNOS, TNFR2, ROR-γt, GATA-3, T-bet, and Foxp3 was determined using quantitative reverse‑transcription polymerase chain reaction (qRT‑PCR). The SASP plus probiotic mixture was more effective in alleviating colitis symptoms, and reducing disease activity scores, and mucosal inflammation. qRT-PCR analysis revealed a significant reduction in T-bet and RORγt levels, while Foxp3 and GATA-3 levels increased in the colons of colitis mice. In addition, the selected strains substantially inhibited the release of inflammatory markers. Administration of LA-5 + BB-12 + SASP resulted in considerably higher inhibition of NO production and cell proliferation than in the other groups (p < 0.001). Treatment with LA-5 + BB-12 + SASP also reduced TNF-α-mediated apoptosis in intestinal epithelial cells (IECs). Survey results highlight that the combination regimen could be a promising strategy for IBD therapy, warranting further study of its clinical application and long-term benefits.

Spontaneous cytokine production by the cells from peripheral blood, lymph nodes, spleen, thymus and skin in a murine model of acute psoriasis-like dermatitis

Imiquimod-induced model of psoriasis in mice is used for the studies in psoriasis. Imiquimod administered as skin application triggers a complex multi-stage process simulating psoriatic inflammation of the skin, accompanied by changes in production of cytokines. The aim of this work was a comprehensive study of their contents in cell supernatants isolated from skin, blood, from central and peripheral lymphoid organs and the effect of imiquimod on these parameters. Forty-six C57BL/6 mice were divided into two groups: (1) control (n = 22), and (2) experimental (n = 24). Development of experimental pathology was evaluated by van de Fits et al. The mice from experimental group were treated with a cream containing 5% imiquimod (62.5 mg/ cm2/ day/mouse) for 7 days. On the 7th day of experiment, the animals were subject to blood sampling, extraction of spleen, lymph nodes, thymus, and skin biopsies were also made. To obtain cell suspensions, the tissues of spleen, lymph nodes, and thymus were crushed in a homogenizer, and then passed through cell filters (50 mcm pore size). The method of spontaneous migration was used to isolate skin cells. The cultures of blood, spleen, lymph nodes, thymus, and skin cells were incubated for 24 hours in RPMI-1640 followed by assessment of spontaneous cytokine production in supernatants. The cytokine level (IFNγ, IL-1β, IL-5, IL-6, IL-10, IL- 17, TNFα, IL-10) was determined using the murine Th1/Th2/Th17 Panel test system. Our study revealed that the cells isolated from blood and lymphoid organs synthesize increased amounts of pro-inflammatory cytokines: IL-1 and IL-17. The most pronounced changes in the cytokine profile are observed in cell supernatants from blood, skin and spleen cultures.

Recombinant Human Proteoglycan Aggrecan-G1 Domain-induced Arthritis (GIA) Mouse Model.

The recombinant human proteoglycan aggrecan-G1 domain (rhG1)-induced arthritis (GIA) mouse model is a complex model of rheumatoid arthritis (RA). In GIA, autoimmune arthritis is induced by repeated intraperitoneal immunization of genetically susceptible BALB/c mice with the rhG1 antigen emulsified in the adjuvant dimethyldioctadecylammonium (DDA). This article describes the steps for producing and purifying the rhG1 antigen, the immunization protocol, methods for following the clinical picture of arthritis, and the evaluation of relevant laboratory parameters. In this model, the autoimmune arthritis develops stepwise, similar to RA: First is the preclinical stage (after the first immunization, days 0-20) with no sign of inflammation but detectable T and B cell activation; next, the stage of early arthritis (after the second immunization, days 21-41), where the first definitive signs of arthritis appear together with autoantibody production; and then the severe late-stage arthritis (after the third immunization, after day 42), which presents with massive inflammation of the limbs, leading to cartilage and bone destruction and finally ankylosis. The protocols described here provide sufficient information for investigators to use the GIA model to study different aspects of autoimmune arthritis. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Induction of recombinant human proteoglycan aggrecan-G1 domain (rhG1)-induced arthritis (GIA) Support Protocol 1: Production of rhG1-Xa-mFc2a fusion protein with CHOK1 mammalian expression system Support Protocol 2: Purification of the rhG1-Xa-mFc2a fusion protein by affinity chromatography Support Protocol 3: Preparation of DDA adjuvant Support Protocol 4: Clinical assessment of arthritis Support Protocol 5: Measurement of serum antibody levels and cytokines Support Protocol 6: Measurement of rhG1-induced proliferation and cytokine production in spleen cell culture Support Protocol 7: Histological assessment of arthritic limbs Support Protocol 8: Evaluation of arthritis with micro-computed tomography.

Mesenchymal Stem Cell-derived Exosome; An Interesting Nanocarrier to Improve Allergen-specific Intranasal Immunotherapy.

Increasing the efficacy of allergen-specific intranasal immunotherapy (INIT) has recently been the main goal of several studies to establish this route as a safe delivery method through mucosal pathways. In this case, the present study evaluated the potential of INIT using ovalbumin (OVA)-loaded mesenchymal stromal/stem cell (MSC)-derived exosomes (Exo-OVA) in an allergic asthma mouse model. Together with control groups, sensitized Balb/c mice underwent intranasal immunotherapy with Exo-OVA (10 μg OVA per dose) for three consecutive weeks. Serum-specific immunoglobulin E (IgE) levels, transforming growth factor-beta (TGF-β), interleukin (IL)-4, and interferon-gamma (IFN-γ) production by cultured spleen cells, lung histopathologic analysis, and nasopharyngeal lavage fluid cellular examinations were then conducted. The results showed that INIT using Exo-OVA significantly increased IFN-γ and TGF-β secretion, while allergen-specific IgE and IL-4 production were dramatically decreased compared to the control group receiving phosphate-buffered saline. In addition, the eosinophil and total cell counts in the nasopharyngeal lavage fluid were reduced, and inflammatory conditions and cell accumulation in lung tissue were ameliorated. In conclusion, the Exo-OVA improved the INIT efficacy compared to free OVA. Therefore, this formulation could be introduced as an effective approach for immunomodulatory purposes with a shorter treatment duration and reduced side effects.

Green tea polyphenols alleviate β-conglycinin-induced anaphylaxis by modulating gut microbiota in rats

Heretofore, there are no effective therapeutic interventions for food allergies induced by β-conglycinin, an major allergen in soybean. The objective of this study was to explore the alleviating effect and underlying mechanism of green tea polyphenols (GTPs) on β-conglycinin-induced anaphylaxis. Twenty-one-day-old weaned BN rats were sensitized by gavage of β-conglycin and then given drinking water containing 1% GTPs. The results showed that β-conglcyinin sensitized rats had increased serum IgE levels and IL-4 level in spleen cell culture supernatant compared with the control group. However, total IgE, β-conglycin-specific IgE and IL-4 levels were significantly decreased by GTPs, suggesting that it weakened Th2-type immune response and restored cytokine homeostasis. The impact of GTPs on gut microbiota mainly focused on the changes in specific microbes, characterized by a significant increase of Bacteroides and other beneficial bacteria, which would contribute to the recovery of gastrointestinal allergies. This study is the first to demonstrate that GTPs, as good immunomodulator, played an important role in alleviating soybean protein allergy, which were associated with the alterations in gut microbiota. These results contribute to the development and application of green tea and provided an effective nutritional therapy strategy for the prevention and treatment of allergic diseases caused by soybean allergens.

Effect of Oleoylethanolamide-Based Dietary Supplement on Systemic Inflammation in the Development of Alimentary-Induced Obesity in Mice.

The complex effect of oleoylethanolamide-based dietary supplement (OEA-DS) was studied in a model of diet-induced obesity in mice. Physiological, biochemical, and immunohistochemical methods were used to reveal differences in the changes in the weight of experimental animals, morphological changes in the spleen tissues, and changes in the cytokine expression profile in the spleen, blood plasma, and macrophage cell culture. First, it is shown that a hypercaloric diet high in carbohydrates and cholesterol led to the development of systemic inflammation, accompanied by organ morphological changes and increased production of proinflammatory cytokines. In parallel, the use of OEA-DS reduced the intensity of cellular inflammatory reactions, accompanied by a decrease in markers of cellular inflammation and proliferation, such as CD68, Iba-1, and Ki67 in the spleen tissue, and stabilized the level of proinflammatory cytokines (IL-1β, IL-6, TNFα) both in animals and in cell culture. In addition, in the macrophage cell culture (RAW264.7), it was shown that OEA-DS also suppressed the production of reactive oxygen species and nitrites in LPS-induced inflammation. The results of this study indicate the complex action of OEA-DS in obesity, which includes a reduction of systemic inflammation.

Immunization with recombinant LiHyp1 protein plus adjuvant is protective against tegumentary leishmaniasis.

Tegumentary leishmaniasis (TL) is the main clinical manifestation of leishmaniasis, and it can cause the infected hosts to self-healing cutaneous lesions until mutilating scars in mucosal membranes, particularly in the nose and throat. The treatment against disease presents problems, and the diagnosis is hampered by variable sensitivity and/or specificity of the tests. In this context, the development of prophylactic vaccines could be considered as a strategy to control the disease. Previously, we showed that the recombinant LiHyp1 protein plus adjuvant protected mice from infection with Leishmania infantum, which causes visceral leishmaniasis. In the present study, we tested whether rLiHyp1 could induce protection against infection with L. amazonensis, a parasite species able to cause TL. We immunized BALB/c mice with rLiHyp1 plus saponin (rLiHyp1/S) or incorporated in micelles (rLiHyp1/M) as adjuvants and performed parasitological and immunological evaluations before and after infection. Results showed that after in vitro stimulation from spleen cell cultures using rLiHyp1 or a Leishmania antigenic extract (SLA), rLiHyp1/S and rLiHyp1/M groups developed a Th1-type immune response, which was characterized by high levels of IFN-γ, IL-2, TNF-α and IL-12 cytokines, nitrite, and IgG2a isotype antibodies when compared to values found in the control (saline, saponin, micelles alone) groups, which showed higher levels of anti-SLA IL-4, IL-10, and IgG1 antibodies before and after challenge. In addition, mice receiving rLiHyp1/S or rLiHyp1/M presented significant reductions in the lesion average diameter and parasite load in the infected tissue and internal organs. Blood samples were collected from healthy subjects and TL patients to obtain PBMC cultures, which were in vitro stimulated with rLiHyp1 or SLA, and results showed higher lymphoproliferation and IFN-γ production after stimulus using rLiHyp1, as compared to values found using SLA. These results suggest that rLiHyp1 plus adjuvant was protective against experimental TL and could also be considered for future studies as a vaccine candidate against human disease.

Molecular and biological properties of the African swine fever virus (Asfarviridae: Asfivirus) isolate ASF/Tatarstan 20/WB-12276

Up-to-date data and full characterization of circulating ASFV isolates play a crucial role in virus eradication and control in endemic regions and countries. The aim of the study was to evaluate and characterize the molecular and biological properties of the ASFV isolate ASF/Tatarstan 20/WB-12276, conduct phylogenetic analysis, and compare the results with isolates circulating in Europe and Asia. For bioassay, eight heads of the Large White pigs weighing 15-20 kg/head were used. Detection of specific anti-ASFV antibodies by ELISA and immunoperoxidase method. Detection of ASFV genome was performed by qPCR. Isolation of ASF/Tatarstan 20/WB-12276 and determination of titer were performed in pig spleen cell culture. Sequencing was carried out by the Sanger method. The virus was characterized as highly virulent and capable of causing acute to subacute forms of ASF. Phylogenetic analysis revealed substitutions in the genome of the ASF/Tatarstan 20/WB-12276 isolate (IGR/I73R-I329L and I267L markers) that supported the clustering of the studied variant with isolates prevalent in most of Europe and Asia. For the first time, the molecular and biological properties of the ASF/Tatarstan 20/WB-12276 virus isolate taken from a wild boar shot on the territory of the Republic of Tatarstan were studied and analyzed.

Comparison of the effects of probiotic strains (Lactobacillus gasseri, Lactiplantibacillus plantarum, Lactobacillus acidophilus, and Limosilactobacillus fermentum) isolated from human and food products on the immune response of CT26 tumor-bearing mice.

This study aimed to compare the effects of the probiotic bacteria, L. gasseri (52b), L. plantarum (M11), L. acidophilus (AC2), and L. fermentum (19SH), isolated from human source and traditional food products on the modulation of the immune system and inflammatory response on BALB/c mouse model bearing CT26 tumor. Five groups of female inbred BALB/c mice were orally administered with the probiotics and their mixes (MIX, at a 1:1 ratio) at varying dosages (1.5 × 108cfu/ml and 1.2 × 109cfu/ml) before and after the injection of a subcutaneous CT26 tumor over the course of 38days via gavage. Finally, their effects on the tumor apoptosis and the cytokine levels in spleen cell cultures were analyzed and compared. M11, MIX, and 52b groups had the greatest levels of interleukin-12 (IL-12) and interferon gamma (IFN-γ) production. The highest production level of granzyme B (GrB) was related to the MIX and 52b groups. Moreover, these groups showed the lowest production level of (IL-4) and transforming growth factor beta (TGF-β). Furthermore, the groups of MIX and 52b demonstrated the greatest amount of lymphocyte proliferation of spleen cells in response to the tumor antigen. The delayed-type hypersensitivity (DTH) response significantly increased in the groups of MIX and 52b compared with the control (p < 0.05). The findings demonstrated that the oral treatment of the human strain (52b) and the combination of these bacteria generated strong T helper type 1 (Th1) immune responses in the tumor tissue of the tumor-bearing mice, which led to the suppression of the tumor development.

Oral administration of procyanidin B2 3,3"-di-O-gallate ameliorates experimental autoimmune encephalomyelitis through immunosuppressive effects on CD4+ T cells by regulating glycolysis

Multiple Sclerosis (MS) is a chronic autoimmune disease of the central nervous system caused by the excessive activation of T cells. Procyanidins are polyphenols that exhibit anti-inflammatory activity. Procyanidin B2 (PCB2) gallate [specifically, PCB2 3,3″-di-O-gallate (PCB2DG)] inhibits cytokine production in T cells by suppressing the acceleration of glycolysis. In this study, we determined the effect of PCB2DG on T cell-mediated autoimmune disease in vivo. We examined the immunosuppressive effects of PCB2DG using an experimental autoimmune encephalomyelitis (EAE) model, which is a classic animal model for MS. Our results indicated that the clinical score for EAE symptoms improved significantly following the oral administration of PCB2DG. This effect was associated with the suppression of T cell-mediated cytokines (e.g., IFN-γ, TNF-α, and IL-17) and infiltrating T cells into the spinal cord, which ameliorated spinal cord injury. In addition, spleen cell culture experiments revealed that the increase of T cell-mediated pro-inflammatory cytokines in EAE mice was significantly decreased following PCB2DG treatment. We further analyzed the glycolytic activity of spleen cells to identify the mechanism of the immunosuppressive effects of PCB2DG. The production of lactate and the expression of glycolytic enzymes and transporters were increased following EAE induction, but not in PCB2DG-treated EAE mice. Collectively, our results indicate that a dietary polyphenol, which has a unique structure, improves the onset of EAE symptoms and inhibits the excessive activation of T cells by influencing glycolysis.

Immune response induced by recombinant pres2/S-protein and a pres2-S-protein fused with a core 18-27 antigen fragment of hepatitis B virus compared to conventional HBV vaccine.

Although comprehensive vaccination is the cornerstone of public health programs to control hepatitis B virus (HBV) infections, 5% of people who receive the existing vaccine do not develop proper immunity against HBV. To overcome this challenge, researchers have tried using various protein fragments encoded by the virus genome to achieve better immunization rates. An important antigenic component of HBsAg called the preS2/S or M protein has also received much attention in this area. The gene sequences of preS2/S and Core18-27 peptide were extracted from the GenBank (NCBI). Final gene synthesis was conducted with pET28. Groups of BALB/c mice were immunized with 10μg/ml of recombinant proteins and 1μg/ml CPG7909 adjuvant. Serum levels of IF-γ, TNF-α, IL-2, IL-4, and IL-10 were measured by ELISA assay method on spleen cell cultures on day 45, and IgG1, IgG2a, and total IgG titers obtained from mice serum were quantified on days 14 and 45. Statistical analysis did not show any significant difference between the groups regarding IF-γ level. There were, however, significant differences in terms of IL-2 and IL-4 levels between the groups receiving preS2/S-C18-27 with and without adjuvant and the groups receiving both preS2/S and preS2/S-C18-27 (Plus Recomb-Plus Recomb: the group of mice that received both preS2/S and preS2/S-C18-27 simultaneously). The strongest total antibody production was induced by immunization with both recombinant proteins without CPG adjuvant. The groups that received both preS2/S and preS2/S-C18-27, whether with or without adjuvant, were significantly different from those that received the conventional vaccine considering most abundant interleukins. This difference suggested that higher levels of efficacy can be achieved by the use of multiple virus antigen fragments rather than using a single fragment.

Immunogenicity of Chitosan-Based Non-invasive Vaccine Strategy Against Mycobacterium tuberculosis

Background: In spite of Bacillus Calmette-Guerin (BCG) vaccination, still tuberculosis caused by Mycobacterium tuberculosis remains a problematic impediment that requires perspective management. The aim of this study was to evaluate the immunogenicity of chitosan nanoparticles containing recombinant mycobacterial proteins and adjuvant in the Balb/C mice through a non-invasive nasal inhalation delivery route and measure the level of cytokines interferon gamma (IFN-γ), interleukin-4 (IL-4), and IL-17. Methods: Thirty mice in five different groups were vaccinated through inhalation with compounds set in different combinations. Two weeks after the last nasal delivery, IFN-γ, IL-4, and IL-17 were measured in spleen cell culture supernatants. Results: The IFN-γ and IL-17 concentrations were found to increase in the groups that received chitosan nanoparticles containing protein and adjuvant alone or as a BCG booster. Our study showed that the chitosan nanoparticle containing protein and adjuvant induced a Th1 response. However, the groups that first received BCG and then chitosan nanoparticles containing protein and adjuvant had the greatest Th1 response in terms of IFN-γ and IL-17 production in all the groups. Conclusion: Our findings showed that the vaccine designed to be administered through the nasal mucosa well stimulates cellular immunity and enhances the BCG vaccine’s effectiveness.

Polynucleotides Compensate for Impaired T-Dependent Antibody Production Induced in C57Bl/6 Mice by a Nucleotide-Free Diet both in Vivo and in Vitro, but a Mononucleotide-Nucleoside Mixture Is Effective Only In Vivo

Actions of nucleotides on in vitro humoral immune responses were studied in mice fed a nucleotide-free diet, a nucleotide-free diet plus a mononucleotide-nucleoside mixture or a nucleotide-free diet plus yeast RNA (polynucleotides). Cultured spleen cells from mice fed a nucleotide-free diet produced fewer numbers of antibody-secreting cells in response to a T-dependent antigen, compared with those from controls fed nucleotide-supplemented diets. Immunoglobulin M concentrations in these supernatants were significantly lower in cultured cells from mice fed the nucleotide-free diet or the nucleotide-free diet plus the mononucleotide/nucleoside mixture compared with concentrations in cells from mice fed the nucleotide-free diet plus RNA. Concanavalin A-potentiated cytokine (interleukin-4 and interleukin-5) production by purified T helper cells was also lower in cultured cells from mice fed a nucleotide-free diet than in those from mice fed nucleotide-supplemented diets. In vivo supplementation with the mononucleotide/nucleoside mixture restored impaired in vitro antibody and concanavalin A-potentiated cytokine production in mice fed a nucleotide-free diet. However, addition of RNA to the culture enhanced antibody production in spleen cells from mice of all diet groups. Supplementing the culture with RNA did not enhance mitogen-potentiated cytokine production. This in vitro action of RNA was retained after the removal of oligonucleotides (molecular weight <1000), but was reduced by modification of bases and cleavage of phosphodiester bonds of RNA. Thus the in vitro action of RNA is mainly attributed to polynucleotides, indicating their potential role in modulation of local humoral immune responses in the body.

A Preliminary Study in Immune Response of BALB/c and C57BL/6 Mice with a Locally Allergic Rhinitis Model.

BALB/c and C57BL/6 mouse strains are commonly used in allergy research. The current study investigated the immunological differences between these two mouse strains with a locally allergic rhinitis model. Eighteen BALB/c and eighteen C57BL/6 mice received different doses of ovalbumin (OVA) intranasally for eight weeks (each mouse strain has three subgroups, 25 mg/mL group, 0.25 mg/mL group, and the PBS group). The allergic symptoms, OVA-specific serum antibody (IgE, IgG1, IgG2a), cytokines (IL-4, IFN-γ, IL-10) in the splenic culture supernatant, infiltrating eosinophils and goblet cells in local nasal mucosa were measured. RNA-seq technology was applied to detect differential gene expression in the local nasal mucosa. With the same dose of OVA stimulation, the exacerbation of allergic symptoms was more pronounced in C57BL/6 than in BALB/c. BALB/c serum IgE, IgG1, and IgG2a gradually increased, and C57BL/6 produced fewer serum antibodies IgE and IgG1, while IgG2a never increased. BALB/c spleen cell culture supernatant IL-4 and IL-10 increased with increasing dose, and IFN-γ increased significantly in the intermediate dose group, while IL-4, IL-10, and IFN-γ did not increase in C57BL/6. The infiltration of eosinophils and goblet cells in both mice was proportional to the dose, while C57BL/6 was elevated more than BALB/c. RNA-seq suggested that the innate immune response, immune system process function, Jun kinase (JNK) pathway, and MAPKK pathway were upregulated in C57BL/6 compared to BALB/c. The core genes responsible for the differential immune response in both mice with allergic rhinitis were Kng2, Kng1, Gnb3, Lpar3, Lpar1, Pik3r1, Pf4, Apob, Rps9, and Fbxo2. There are significant differences in the immunologic responses between BALB/c mice and C57BL/6 mice. BALB/c mice developed mild local allergic inflammatory reactions and strong systemic immune responses. In contrast, C57BL/6 mice had stronger local allergic inflammatory responses and relatively mild systemic immune responses. Different mice strains can be selected according to the research purpose.

Exploring drug repositioning for leishmaniasis treatment: Ivermectin plus polymeric micelles induce immunological response and protection against tegumentary leishmaniasis

Leishmania amazonensis can cause a wide spectrum of the clinical manifestations of leishmaniasis in humans. The development of new therapeutics is a long and expensive task; in this context, drug repositioning could be considered a strategy to identify new biological actions of known products. In the present study, ivermectin (IVE) was tested against distinct Leishmania species able to cause disease in humans. In vitro experiments showed that IVE was effective to reduce the infection degree and parasite load in Leishmania donovani- and L. amazonensis-infected macrophages that were treated with it. In addition, using the culture supernatant of treated macrophages, higher production of IFN-γ and IL-12 and lower levels of IL-4 and IL-10 were found. Then, IVE was used in a pure form or incorporated into Poloxamer 407-based polymeric micelles (IVE/M) for the treatment of L. amazonensis-infected BALB/c mice. Animals (n = 16 per group) were infected and later received saline, empty micelles, amphotericin B (AmpB), IVE, or IVE/M. They were euthanized at one (n = 8 per group) and 30 (n = 8 per group) days after treatment and, in both endpoints, immunological, parasitological, and biochemical evaluations were performed. Results showed that both IVE and IVE/M induced higher levels of IFN-γ, IL-12, GM-CSF, nitrite, and IgG2a antibodies, as well as higher IFN-γ expression evaluated by RT-qPCR in spleen cell cultures. Such animals showed low organic toxicity, as well as significant reductions in the lesion’s average diameter and parasite load in their infected tissue, spleen, liver, and draining lymph node. The efficacy was maintained 30 days post-therapy, while control mice developed a polarized Th2-type response and high parasite load. In this context, IVE could be considered as a new candidate to be applied in future studies for the treatment against distinct Leishmania species.

Receptor-binding domain-based SARS-CoV-2 vaccine adjuvanted with cyclic di-adenosine monophosphate enhances humoral and cellular immunity in mice.

Novel adjuvants are highly desired to improve immune responses of SARS-CoV-2 vaccines. This work reports the potential of the stimulator of interferon genes (STING) agonist adjuvant, the cyclic di-adenosine monophosphate (c-di-AMP), in a SARS-CoV-2 vaccine based on the receptor binding domain (RBD). Here, mice immunized with two doses of monomeric RBD adjuvanted with c-di-AMP intramuscularly were found to exhibit stronger immune responses compared to mice vaccinated with RBD adjuvanted with aluminium hydroxide (Al(OH)3) or without adjuvant. After two immunizations, consistent enhancements in the magnitude of RBD-specific IgG antibody response were observed by RBD+c-di-AMP (mean:15360) compared to RBD+Al(OH)3 (mean:3280) and RBD alone (n.d.). Analysis of IgG subtypes indicated a predominantly Th1-biased immune response (IgG2c, mean:14480; IgG2b, mean:1040, IgG1, mean:470) in mice vaccinated with RBD+c-di-AMP compared to a Th2-biased response in those vaccinated with RBD+Al(OH)3 (IgG2c, mean:60; IgG2b: n.d.; IgG1, mean:16660). In addition, the RBD+c-di-AMP group showed better neutralizing antibody responses as determined by pseudovirus neutralization assay and by plaque reduction neutralization assay with SARS-CoV-2 WT. Moreover, the RBD+c-di-AMP vaccine promoted IFN-γ secretion of spleen cells cultures after RBD stimulation. Furthermore, evaluation of IgG-antibody titers in aged-mice showed that di-AMP was able to improve RBD-immunogenicity at old-age after 3 doses (mean:4000). These data suggest that c-di-AMP improves immune responses of a SARS-CoV-2 vaccine based on RBD, and would be considered a promising option for future COVID-19 vaccines. This article is protected by copyright. All rights reserved.

PPD in HBsAg vaccine formulation suppressed IFN-γ and IL-4 cytokine responses and induced long-lived humoral immune responses: Results from 220-day monitoring of specific IgG responses.

Here, immune responsesand long-lived IgG responses of HBsAg-Alum, HBsAg-MF59, as well as HBsAg-MF59 were compared when formulated with PPD. BALB/cmice were vaccinatedsubcutaneously three times withatwo-week-interval. Then, specific IgG, long-lived IgG responses up to 220 days,andIgG1/IgG2aisotypes,andIFN-γ and IL-4 on spleen cell culture supernatant were assessed using ELISA. IFN-γ cytokine response between MF59- and Alum-adjuvanted vaccines did not show a significant difference. HBsAg-Alum revealed an increase in IL-4 cytokineversus HBsAg-MF59 at borderline(P=0.0553).In addition, HBsAg-MF59+PPD 10 µg showed a significant decrease in IL-4 and IFN-γ cytokinesversusHBsAg-MF59. Furthermore, HBsAg-MF59+PPD10 µg showed a significant increase intheIL-2/IL-4 ratioversusHBsAg-MF59 (P=0.0339).Specific IgG antibody showed a significant increase in HBsAg-MF59, as compared with HBsAg-Alum. Furthermore, HBsAg-MF59 plus PPD showed a significant increase in IgG responsesversusHBsAg-MF59 and HBsAg-Alum groups. Long-lived IgGresponses showeda significant increase in HBsAgMF59 versus HBsAg-Alum group and PPD in the HBsAg-MF59 vaccine formulation, resulting in a significant increase in IgG responses versus HBsAg-MF59 group. In addition,HBsAg-MF59 plus PPDsuppressed IgG1 response versus HBsAg-Alum. However, HBsAg-MF59 showed a significant increase in IgG2α versustheHBsAg-Alum group (P=0.0190). Immunization with HBsAg-MF59+PPD (10 µg) showed a significant increase versustheHBsAg-MF59 group (P=0.0040).IgG2a/IgG1 ratioinHBsAg-MF59+PPD1µgandHBsAg-MF59+PPD10 µggroups showed a significant increaseversusHBsAg-MF59 groups(P<0.0345). PPD leads toamore potent long-lived IgG responses intheHBsAg vaccine, highlighting its potentialasa component of a complex adjuvant.

Combined Silymarin and Cotrimoxazole Therapy Attenuates Pulmonary Fibrosis in Experimental Paracoccidioidomycosis.

Paracoccidioidomycosis (PCM), which mainly affects rural workers, is a systemic mycosis caused by the Paracoccidioides genus that induces pulmonary sequelae in most adult patients, causing serious disability and impairing their quality of life. Silymarin is herbal medicine with an effective antifibrotic activity. Considering that in PCM, antifibrotic treatment is still not available in pulmonary fibrosis, we aimed to evaluate combined silymarin and cotrimoxazole (CMX) therapy via the intratracheal route in BALB/c mice infected with P. brasiliensis yeast. After 12 weeks of treatment, the lungs were collected for the determination of fungal burden, production of OH-proline, deposition of collagen fibers, pulmonary concentrations of cytokines, and expression of fibronectin, α-SMA, MMP-2, MMP-9, and TIMP-2. Spleen cell cultures were also performed. Our results showed that infected mice treated with combined silymarin/CMX showed lower deposition of collagen fibers in the lungs and lower pulmonary concentrations of hydroxyproline than the placebo groups. Decreased levels of TGF-β1 and fibronectin and high levels of MMP-2 and IFN-γ were also observed in this group of mice. Collectively, our findings indicate that the combination of antifungal treatment with silymarin has a potent antifibrotic effect associated with an immunomodulatory effect that potentializes the antifungal immune response.

A Recombinant Chimeric Protein-Based Vaccine Containing T-Cell Epitopes from Amastigote Proteins and Combined with Distinct Adjuvants, Induces Immunogenicity and Protection against Leishmania infantum Infection.

Currently, there is no licensed vaccine to protect against human visceral leishmaniasis (VL), a potentially fatal disease caused by infection with Leishmania parasites. In the current study, a recombinant chimeric protein ChimT was developed based on T-cell epitopes identified from the immunogenic Leishmania amastigote proteins LiHyp1, LiHyV, LiHyC and LiHyG. ChimT was associated with the adjuvants saponin (Sap) or monophosphoryl lipid A (MPLA) and used to immunize mice, and their immunogenicity and protective efficacy were evaluated. Both ChimT/Sap and ChimT/MPLA induced the development of a specific Th1-type immune response, with significantly high levels of IFN-γ, IL-2, IL-12, TNF-α and GM-CSF cytokines produced by CD4+ and CD8+ T cell subtypes (p < 0.05), with correspondingly low production of anti-leishmanial IL-4 and IL-10 cytokines. Significantly increased (p < 0.05) levels of nitrite, a proxy for nitric oxide, and IFN-γ expression (p < 0.05) were detected in stimulated spleen cell cultures from immunized and infected mice, as was significant production of parasite-specific IgG2a isotype antibodies. Significant reductions in the parasite load in the internal organs of the immunized and infected mice (p < 0.05) were quantified with a limiting dilution technique and quantitative PCR and correlated with the immunological findings. ChimT/MPLA showed marginally superior immunogenicity than ChimT/Sap, and although this was not statistically significant (p > 0.05), ChimT/MPLA was preferred since ChimT/Sap induced transient edema in the inoculation site. ChimT also induced high IFN-γ and low IL-10 levels from human PBMCs isolated from healthy individuals and from VL-treated patients. In conclusion, the experimental T-cell multi-epitope amastigote stage Leishmania vaccine administered with adjuvants appears to be a promising vaccine candidate to protect against VL.

Protection against genotype VII Newcastle disease virus challenge by a minicircle DNA vaccine coexpressing F protein and chicken IL-18 adjuvant

Genotype VII Newcastle disease virus (NDV) is still one of the most important virus threats severely affecting poultry production worldwide. Although inactivated vaccines are commercially available, there is still an urgent need to develop novel vaccine candidates for convenient and affordable vaccine application. Oral immunization using live attenuated bacteria such as Salmonella has recently attracted increasing interest, and in a previous study, we used a regulated delayed lysis Salmonella vector to deliver a DNA vaccine encoding the F protein and chicken IL-18 adjuvant together, named pYL23. To further improve its efficiency, we employed a novel in vivo minicircle DNA (mcDNA) platform to construct pYL58, which could maintain the complete plasmid during in vitro culture conditions and then transform into mcDNA in vivo whenever the plasmid was delivered by Salmonella into host cells. Compared with immunization with the parental strain harboring plasmid pYL23, immunization with Salmonella with pYL58 induced increased levels of serum IgY and mucosal sIgA in chickens, especially the intestinal and tracheal sIgA levels. Production of cytokines, including IL-4, IFN-γ, IL-18 and IFN-α, was also determined in serum and spleen cell culture supernatants after the 3rd immunization, and the results showed that the production of IFN-γ in the pYL58 group was significantly increased compared with that in the negative control group. Interestingly, compared with pYL23, significantly increased production of IFN-α in the cell supernatants from the pYL58 group was also observed. In addition, the CCK-8 assay results showed that the minicircle pYL58 significantly increased spleen cell proliferation. After virulent VII NDV challenge, pYL58 immunization could provide 70% protection compared with 50% protection in the pYL23 group, together with decreased virus titers in chicken lung samples at Day 5 and virus shedding at Days 3 and 5 post-challenge. This study demonstrated that the application of mcDNA technology dramatically increased the DNA vaccine efficiency, providing additional support for the use of our mcDNA platform in the veterinary field.