Enhanced Lymphocyte Proliferation Research Articles

Surface-Engineered Polygonatum Sibiricum Polysaccharide CaCO3 Microparticles as Novel Vaccine Adjuvants to Enhance Immune Response.

Micro- and nanoparticles delivery systems have been widely studied as vaccine adjuvants to enhance immunogenicity and sustain long-term immune responses. Polygonatum sibiricum polysaccharide (PSP) has been widely studied as an immunoregulator in improving immune responses. In this study, we synthesized and characterized cationic modified calcium carbonate (CaCO3) microparticles loaded with PSP (PEI-PSP-CaCO3, CTAB-PSP-CaCO3), studied the immune responses elicited by PEI-PSP-CaCO3 and CTAB-PSP-CaCO3 carrying ovalbumin (OVA). Our results demonstrated that PEI-PSP-CaCO3 significantly enhanced the secretion of IgG and cytokines (IL-4, IL-6, IFN-γ, and TNF-α) in vaccinated mice. Additionally, PEI-PSP-CaCO3 induced the activation of dendritic cells (DCs), T cells, and germinal center (GC) B cells in draining lymph nodes (dLNs). It also enhanced lymphocyte proliferation, increased the ratio of CD4+/CD8+ T cells, and elevated the frequency of CD3+ CD69+ T cells in spleen lymphocytes. Therefore, PEI-PSP-CaCO3 microparticles induced a stronger cellular and humoral immune response and could be potentially useful as a vaccine delivery and adjuvant system.

Exploring the immunomodulatory and antioxidant capacities of Berberis aristata in avian lymphocytes

India is one of the leading producers for eggs and broilers globally and thus has witnessed significant growth in the poultry sector. Different poultry stressors can negatively impact the growth, gut health, immune function and production reproductive performances of poultry. Antibiotic growth promoters (AGPs) have been used in the poultry industry as they also combat stress in poultry along with growth promotion. But the use of antimicrobials as growth promoter raises the concern of antibiotic resistance and its potential hazardous effect on human health as well as the environment. Several other alternatives are available for AGPs such as acidifiers, probiotics, prebiotics, antibacterial peptides and phytobiotics. Phytobiotics are known to possess several benefits for poultry as well as livestock such as immunomodulation, anti-inflammatory effect, antioxidant effect, maintain intestinal health etc. One such important plant is Berberis aristata belonging to the family Berberidaceae which is used in traditional system of medicine for the management of various inflammatory disorders. In the present study aqueous root extract of Berberis aristata (BAE) was evaluated for its immunomodulatory and antioxidant activity. The extraction yield of the roots of Berberis aristata in water was about 9.78%. The BAE showed presence of phenolics, flavonoids, tannins, terpenoids and contained about 104.97 mg/gm of BAE and 83.14 mg/gm of BAE of phenolics and flavonoids, respectively. BAE showed significant antioxidant activity in DPPH free radical scavenging assay. Maximum non-cytotoxic dose (MNCD) of BAE for lymphocyte culture was determined to be 600 µg/ ml. Lymphocytes proliferation assay (LPA) showed that BAE enhanced lymphocyte proliferation of B-cells stimulated by lipopolysaccharide (LPS) and T-cells stimulated by Concanavalin A and Phytohaemagglutinin M (PHA). Treatment with BAE significantly reduced lipid peroxidation (LPO) and increased the level of reduced glutathione, superoxide dismutase, and catalase in chicken lymphocytes, thus indicating antioxidant potential of BAE. The study reveals significant immunomodulatory and antioxidant properties of BAE, thus suggesting that it could be a potential alternative to AGPs in poultry production. But further in vivo studies are required to explore its efficacy and safety for its application in commercial poultry farming.

Peripheral blood regulatory B and T cells are decreased in patients with focal epilepsy

Patients with focal epilepsy of unknown cause (FEoUC) may display T cell infiltration in post-surgery brain specimens and increased serum levels of pro-inflammatory cytokines produced by B and T cells, indicating potential involvement of adaptive immunity. Our study aimed to investigate the peripheral blood distribution of B and T cell subgroups to find clues supporting the distinct organization of adaptive immunity in FEoUC. Twenty-two patients with FEoUC and 25 age and sex matched healthy individuals were included. Peripheral blood mononuclear cells were immunophenotyped by flow cytometry. Expression levels of anti-inflammatory cytokines and FOXP3 were measured by real-time PCR. Carboxyfluorescein succinimidyl ester (CFSE) proliferation assay was conducted using CD4+ T cells. Patients with FEoUC showed significantly decreased regulatory B (Breg), B1a, plasmablast and regulatory T (Treg) cell percentages, and increased switched memory B and Th17 cell ratios. Moreover, CD4+CD25+CD49d− Tregs of FEoUC patients displayed significantly reduced TGFB1 and FOXP3, but increased IL10 gene expression levels. CD4+ helper T cells of patients with FEoUC gave more exaggerated proliferation responses to phytohemagglutinin, anti-CD3 and anti-CD28 stimulation. Patients with FEoUC display increased effector lymphocyte, decreased regulatory lymphocyte ratios, and impaired Treg function and enhanced lymphocyte proliferation capacity. Overall, this pro-inflammatory phenotype lends support to the involvement of adaptive immunity in FEoUC.

Immunization of BALB/c Mice with Killed Tachyzoites of Toxoplasma gondii against Acute Toxoplasmosis.

Toxoplasma gondii with widespread distribution infects over one third of human populations in the world and can cause serious life-threatening diseases especially for the immunodeficient patients in acute toxoplasmosis. As the clinical pharmaceutical drugs with severe side effects for treatment and non-ideal extant vaccines for prevention, more work starves to be done for keeping advantages in the athletics. Aluminum adjuvant and hybrid formaldehyde-killed tachyzoites of T. gondii RH and GT1 isolates were prepared to intramuscularly immunize BALB/c mice for five times at 0, 3, 7, 14 and 21 days post first injection. The triggered humoral and cellular immune responses at two weeks post the last immunization and the survival times of infected mice were examined for the hybrid immunization scheme judgement. The anti-RH and anti-GT1 specific antibodies were both increased at one week prior to challenge (P < 0.05), and the survival times of immunized mice (7.33 ± 0.71 d for RH, 7.22 ± 0.97 d for GT1) against acute toxoplasmosis were significantly prolonged by the immunizations performed in the study compared to blank control (6.67 ± 0.50 d for RH, 6.33 ± 0.71 d for GT1; P < 0.05), with the higher IFN-γ, IL-2 and IL-12p70 in sera, the elevated CD3e+CD4+ T and CD3e+CD8a+ T cells, and the enhanced lymphocyte proliferation in spleen (P < 0.05). The hybrid killed tachyzoites with aluminum adjuvant induced humoral and cellular immune responses of mice, and offered mildly protective efficacy against acute toxoplasmosis.

Identification of IL-27 as a novel regulator of major histocompatibility complex class I and class II expression, antigen presentation, and processing in intestinal epithelial cells.

Antigen presentation via major histocompatibility complex (MHC) class I and class II receptors plays a fundamental role in T cell-mediated adaptive immunity. A dysregulation of this fine-tuned recognition might result in the development of autoimmune diseases such as inflammatory bowel diseases that are characterized by chronic relapsing inflammation of the intestinal tract and a damaged intestinal epithelial barrier. While MHCII receptors are usually expressed by professional antigen presenting cells (APC) only, there is increasing evidence that non-immune cells such as intestinal epithelial cells (IEC) might express MHCII upon stimulation with IFN-γ and thus act as non-professional APC. However, little is known about other factors regulating intestinal epithelial MHC expression. Here, we identify IL-27 as an inducer of different MHCI and MHCII receptor subtypes and the invariant chain (CD74/li) in IEC via the STAT1/IRF1/CIITA axis. CIITA, MHCII, and CD74 expression was significantly increased in IEC from Crohn's disease (CD) patients with active disease compared to controls or CD patients in remission. IEC phagocytosed and digested external antigens and apoptotic cells. IL-27 strongly stimulated antigen processing via the immunoproteasome in a IRF1-dependent manner. In co-culture experiments, antigen-primed IEC strongly enhanced lymphocyte proliferation and IL-2 secretion, dependent on direct cell-cell contact. IL-27 pretreatment of IEC significantly increased CD4+ T cell proliferation and reduced IL-2 levels in lymphocytes in coculture. In summary, we identified IL-27 as a novel regulator of IEC antigen processing and presentation via MHCI and MHCII receptors, underscoring the importance of IEC as non-professional APC.

Development and evaluation of a multi-epitope subunit vaccine against Mycoplasma synoviae infection

Mycoplasma synoviae is an extremely significant avian pathogen, causing substantial financial harm to poultry farmers worldwide, and impacting both chicken and turkey production. Multi-epitope vaccines offer higher immunity and lower allergenicity compared to conventional vaccines. In this study, our objective is to develop a multi-epitope vaccine for M. synoviae (MSMV) and to evaluate the immune responses and protective efficacy of MSMV in chickens. We successfully identified a total of 14 B-cell, 5 MHC-I, and 16 MHC-II binding epitopes from the immunodominant proteins RS01790, BMP, GrpE, RS00900, and RS00275. Subsequently, we synthesized the multi-epitope vaccine by connecting all conserved epitopes using appropriate linkers. The resulting MSMV demonstrated notable antigenicity, non-allergenic properties, and stability. Notably, the MSMV effectively stimulated high levels of antibody production in chickens. Furthermore, MSMV the vaccine elicited a robust cellular immune response in chickens, characterized by a well-balanced Th1/Th2-type cytokine profile and enhanced lymphocyte proliferation. In immune protection experiments, the vaccinated chickens exhibited reduced air sac lesion scores and tracheal mucosal thickness compared to their non-vaccinated chickens. Additionally, vaccinated chickens displayed lower M. synoviae loads in throat swabs. These findings collectively suggested that the MSMV holds significant potential as a promising vaccine candidate for managing M. synoviae infections.

Analysis of Intestinal Metabolites in SR-B1 Knockout Mice via Ultra-Performance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry.

Scavenger receptor class B type 1 (SR-B1), a multiligand membrane receptor, is expressed in a gradient along the gastrocolic axis. SR-B1 deficiency enhances lymphocyte proliferation and elevates inflammatory cytokine production in macrophages. However, whether SR-B1 affects intestinal metabolites is unclear. In this study, we detected metabolite changes in the intestinal tissue of SR-B1-/- mice, including amino acids and neurotransmitters, by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) and HPLC. We found that SR-B1-/- mice exhibited changes in intestinal lipid metabolites and metabolic pathways, including the glycerophospholipid, sphingolipid, linoleic acid, taurine, and hypotaurine metabolic pathways. SR-B1 deficiency influenced the contents of amino acids and neurotransmitters in all parts of the intestine; the contents of leucine (LEU), phenylalanine (PHE), tryptophan (TRP), and tyrosine (TYR) were affected in all parts of the intestine; and the contents of 3,4-dihydroxyphenylacetic acid (DOPAC) and dopamine (DA) were significantly decreased in both the colon and rectum. In summary, SR-B1 deficiency regulated intestinal lipids, amino acids, and neurotransmitter metabolism in mice.

Assessment of the role of anthocyanin standardized elderberry (Sambucus nigra) extract as an immune-stimulating nutraceutical of Nile tilapia, Oreochromis niloticus.

The study of nutraceuticals and their connection to immunity is an expanding field of research. The use of nutraceuticals to alleviate stress and enhance immunity in adverse aquaculture environments have been examined to a certain extent. To elucidate the understanding, we focused on the immunological effect of membrane-separated 13% anthocyanin standardized elderberry (EB) extract with maltodextrin excipient, widely used first-line nutraceuticals to augment the immunity, in aquaculture fish, Nile tilapia. To evaluate the potential of EB-extract, we assessed their capability to enhance lymphocyte proliferation and interleukin-2 production in an in-vitro condition using spleen and thymus lymphocytes. The experiments on spleen and thymus T-cells demonstrated significantly higher T-cell proliferation by EB-extract when lectin mitogen Con A was present as a stimulator. Likewise, our spleen B-cell proliferation result reveals a significant effect of EB-extracts, along with B-cell stimulator non-lectin mitogen LPS. Further, the quantification of IL-2 indicates elevated IL-2 levels when spleen T-cells were cultured with EB-extracts and with Con A present as a stimulator. These suggest that 13% anthocyanin standardized EB-extracts can aggrandize fish cells' cellular and humoral immune responses. With further research, elderberry extracts could be used to supplement commercial feed in aquaculture to reduce stress and stimulate the immune response.

The Influence of Heterochronic Non-Myeloablative Bone Marrow Transplantation on the Immune System, Frailty, General Health, and Longevity of Aged Murine Recipients.

The stem cell theory of aging postulates that stem cells become inefficient at maintaining the original functions of the tissues. We, therefore, hypothesized that transplanting young bone marrow (BM) to old recipients would lead to rejuvenating effects on immunity, followed by improved general health, decreased frailty, and possibly life span extension. We developed a murine model of non-myeloablative heterochronic BM transplantation in which old female BALB/c mice at 14, 16, and 18(19) months of age received altogether 125.1 ± 15.6 million nucleated BM cells from young male donors aged 7–13 weeks. At 21 months, donor chimerism was determined, and the immune system’s innate and adaptive arms were analyzed. Mice were then observed for general health and frailty until spontaneous death, when their lifespan, post-mortem examinations, and histopathological changes were recorded. The results showed that the old mice developed on average 18.7 ± 9.6% donor chimerism in the BM and showed certain improvements in their innate and adaptive arms of the immune system, such as favorable counts of neutrophils in the spleen and BM, central memory Th cells, effector/effector memory Th and Tc cells in the spleen, and B1a and B1b cells in the peritoneal cavity. Borderline enhanced lymphocyte proliferation capacity was also seen. The frailty parameters, pathomorphological results, and life spans did not differ significantly in the transplanted vs. control group of mice. In conclusion, although several favorable effects are obtained in our heterochronic non-myeloablative transplantation model, additional optimization is needed for better rejuvenation effects.

Etiopathogenetic features of hyperprolactinemia in childhood

In recent years, the problem of hyperprolactinemia in children remains relevant because it is one of the most common pathologies of the hypothalamic-pituitary system, causing impaired fertility and reproductive function in adulthood. According to population studies, its incidence is 0.5 % in females, exceeding this figure in males by 10 times. Prolactin has: immunomodulatory effect, enhancing lymphocyte proliferation, phagocytic capacity of macrophages, IgA synthesis; analgesic effect; promotes postnatal growth of the body by inducing the activity of genes associated with growth; activates the proliferation of keratinocytes, epithelial cells of the prostate; participates in the regulation of metabolism, water-electrolyte balance, inhibiting the excretion of potassium and sodium ions by the kidneys; influences human behavior by accelerating neurogenesis, memory, learning and providing neuroprotection; induces surfactant production; stimulates lipogenesis. Prolactin levels increase due to physiological hyperestrogenemia, which blocks the inhibitory effect of dopamine on prolactin secretion and occurs during lactation, pregnancy and some other physiological states. Pathological hyperprolactinemia occurs in children with secondary hypogonadotropic hypogonadism, organic lesions of the suprasellar area of the brain and may be secondary (symptomatic). In the etiological structure of hyperprolactinemia syndrome, the largest proportion (60 %) in children and adolescents belongs to prolactinomas (pituitary adenomas that secrete prolactin), idiopathic hyperprolactinemia (22.7 %) and iatrogenic hyperprolactinemia induced by 6 drugs (4 % of cases). Given that the lion’s share of hyperprolactinemia in childhood is associated with the presence of pituitary prolactinoma, characterized by latent gradual progression of reproductive disorders, growth processes and neurological symptoms, the objective of this article is to focus on the pleiotropic effects of prolactin in the body, which controls more than 300 biological functions, epidemiological, etiological and pathogenetic mechanisms, on the features of the clinical classification of hyperprolactinemia to form a modern understanding of this problem.

Alum and metoclopramide synergistically enhance cellular and humoral immunity after immunization with heat-killed Salmonella typhimurium vaccine

Typically, the killed form of microorganisms in combination with alum does not produce strong cellular immune responses. A recent investigation has indicated the role of dopamine D2 receptor antagonists like metoclopramide in reducing the polarization of immune responses toward Th2 immunity. This study was performed to evaluate the effects of a combination of alum and metoclopramide on the induction of cellular and humoral immunity in response to a heat-killed preparation ofSalmonella typhimurium(HKST). Wistar rats were immunized with the HKST vaccine alone or in combination with alum, metoclopramide, or the alum-metoclopramide mixture twice with a two-week interval. Fourteen days after the last vaccination, immune responses against S. typhimurium and the protective potential of the vaccines were assessed. The combination of alum and metoclopramide as an adjuvant augmented the potential of the HKST vaccine to enhance lymphocyte proliferation, delayed-type hypersensitivity reaction, and antibody titer. These results were concurrent with the polarization of immune response towards the Th1 response and improving protective immunity against S. typhimurium. Overall, the combination of alum and metoclopramide as an adjuvant synergistically enhanced cellular and humoral immunity after immunization with the HKST vaccine.

Abstract 1720: Ax-101, an immunostimulatory small molecule, markedly enhances the antitumor activity of PD1 immune checkpoint blockade in multiple preclinical solid tumor models

Abstract Ax-101, a small-molecule immunomodulator with a yet-to-be elucidated MoA, enhances lymphocyte proliferation, induces a Th1 profile, increases T-cell cytotoxicity, and improves the M1/M2 ratio. Specific Ax-101 effects include upregulated cell-surface TNFalpha (sTNF) on human T cells and monocytes, increased (&amp;gt;7.5x) T-cell cytotoxicity, upregulation by human PBMC of antitumor cytokines (e.g., IL-2, IFN-gamma, TNFalpha) and downregulation of cytokines that mediate immune evasion (e.g., IL-10), and decreased immune-suppressive myeloid cells. Syngeneic mouse cancer models including bladder (MBT-2), colorectal (CT-26), melanoma (Cloudman), and lymphoma (A20) show the addition of Ax-101 to anti-PD1 to improve outcomes. For example, neither Ax-101 nor anti-PD1 monotherapy had significant effects on mean tumor volume (MTV) in MBT-2 mice, while an Ax-101/anti-PD1 (same doses/regimen) combo resulted in up to 44% reduction in MTV c/w anti-PD1 alone (p &amp;lt; 0.05). Further, 30% (3/10) of MBT-2 mice achieved CR with the combo, whereas no CRs were seen with anti-PD1 alone. In CT-26 mice, 25% (2/8) achieved CR, whereas no CRs occurred with anti-PD1 only; subset analysis of mice exhibiting at least some antitumor response to anti-PD1 alone (6/8) or the Ax-101/anti-PD1 combo (5/8) revealed a 40% CR rate and MTV reduction of up to 75% in combo-treated animals. In Cloudman melanomas, all (5/5) mice receiving Ax-101/anti-PD1 throughout their treatment achieved CR. Importantly, in mice with rapidly growing melanomas refractory to anti-PD1 for 12 d, Ax-101 addition reversed growth, with 4/5 mice achieving CR. Of note, 9 Cloudman mice achieving CR were re-injected with 3x the melanoma cells they initially received and followed with no therapy. Only 1/9 mice developed tumor over 73 d; thus, Ax-101/anti-PD1 may elicit a vaccine-like effect. Anti-PD1 alone and the Ax-101/antiPD1 combo in A20 mice resulted in 23% and 40% lower MTVs c/w control. Ax-101 was previously in Ph 1/2 monotherapy studies in follicular lymphoma (FL) and myeloma (M) (CT.gov IDs: NCT00006466, NCT00007839). Thirty-two patients received 2 µg SQ Ax-101 q2 wkly or wkly for up to 18 months. No Grade 3 or higher toxicities were observed. Five of 14 FL patients showed tumor reduction from 16-64%, while 1/17 M patients showed 50% reduced M-protein; maximum responses occurred between 43 days and over 1 year. Increased PBMC sTNF was seen in all patients tested (8 with FL, 6 with M) (p = 0.0006). Consistent with Ax-101 activity depending on a functional immune system, delayed type hypersensitivity (DTH) testing showed all responders to be DTH+ (5 tumor reduction, 4 SD); 5 anergic (DTH-) patients had SD at best (2 SD, 3 worse). Current Ax-101 clinical development will leverage its beneficial immunostimulatory properties to augment the efficacy of anti-PD1 inhibitors such as pembrolizumab, nivolumab and cemiplimab. Citation Format: Stephan W. Morris, Betsy Fisher, Kent Murphy. Ax-101, an immunostimulatory small molecule, markedly enhances the antitumor activity of PD1 immune checkpoint blockade in multiple preclinical solid tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1720.

Difluoromethylornithine (DFMO), an Inhibitor of Polyamine Biosynthesis, and Antioxidant N-Acetylcysteine Potentiate Immune Response in Mice to the Recombinant Hepatitis C Virus NS5B Protein

Hepatitis C virus (HCV) is one of the main triggers of chronic liver disease. Despite tremendous progress in the HCV field, there is still no vaccine against this virus. Potential vaccines can be based on its recombinant proteins. To increase the humoral and, especially, cellular immune response to them, more effective adjuvants are needed. Here, we evaluated a panel of compounds as potential adjuvants using the HCV NS5B protein as an immunogen. These compounds included inhibitors of polyamine biosynthesis and urea cycle, the mTOR pathway, antioxidants, and cellular receptors. A pronounced stimulation of cell proliferation and interferon-γ (IFN-γ) secretion in response to concanavalin A was shown for antioxidant N-acetylcysteine (NAC), polyamine biosynthesis inhibitor 2-difluoromethylornithine (DFMO), and TLR9 agonist CpG ODN 1826 (CpG). Their usage during the immunization of mice with the recombinant NS5B protein significantly increased antibody titers, enhanced lymphocyte proliferation and IFN-γ production. NAC and CpG decreased relative Treg numbers; CpG increased the number of myeloid-derived suppressor cells (MDSCs), whereas neither NAC nor DFMO affected MDSC counts. NAC and DFMO suppressed NO and interleukin 10 (IL-10) production by splenocytes, while DFMO increased the levels of IL-12. This is the first evidence of immunomodulatory activity of NAC and DFMO during prophylactic immunization against infectious diseases.

Immune-enhancing Effect of Bengkoang (Pachyrhizus erosus (l.) Urban) Fiber Fractions on Mouse Peritoneal Macrophages, Lymphocytes, and Cytokines

Background: This study was conducted to evaluate the immunomodulatory effects of bengkoang (Pachyrhizus erosus [L.] Urban) fiber extract (BFE) fraction on mouse peritoneal macrophages, lymphocytes, and cytokines. Materials and Methods: BFE was prepared by heat-extraction from the bengkoang fiber in distilled water at 121°C for 20 min. Fraction of BFE including BEF-A, BEF-B, BEF-D, and BEF-E were prepared by precipitation method with cold ethanol and potassium hydroxide. The phagocytic activity of macrophages was observed by a phagocytosis assay using mouse macrophages. The lymphocyte proliferation assay was performed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and measuring the absorbance at 550 nm. Also, the production of cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 was determined. Results: The BFE enhanced the phagocytic activity by increasing the phagocytic index and capacity of mouse peritoneal macrophages. The phagocytic capacity of mouse peritoneal macrophages was significantly increased after the treatment of BFE, BFE-B, and BFE-E compared with control. The fractions BFE-A, BFE-B, BFE-D, BFE-E, and pectin could stimulate phagocytic activity by increasing the phagocytic index. There were no significant differences after treatment with fiber fractions in enhancing lymphocyte proliferation, but pectin could stimulate the lymphocyte proliferation. Also, the fraction of BFE-A could enhance TNF-α and IL-10 production. After treatment with BFE-B, there were increases in TNF-α and IL-6 production but decreases in IL-10 production. The fraction of BFE-D could also stimulate TNF-α production, and BFE-E could reduce IL-10 production. Conclusion: The fiber fractions of bengkoang showed an immune-enhancing effect, stimulated both TNF-α and IL-6 production, and suppressed IL-10.

Immunological activities of the aqueous extracts of Cistanche deserticola as a polysaccharide adjuvant for inactivated foot-and-mouth disease vaccines

ABSTRACTInactivated foot-and-mouth disease (FMD) vaccines generally require adjuvants to enhance the immunogenicity. To test whether the aqueous extracts of Cistanche deserticola (AECD) could be developed into a polysaccharide adjuvant for inactivated FMD vaccines in mice. Experimental vaccines were prepared with inactivated FMD viral antigen plus AECD or inactivated FMD vaccine plus AECD to subcutaneously immunize mice. AECD developed an FMDV-specific humoral response by increasing IgG antibodies and IL-4 in CD4+ T cells and enhanced lymphocyte proliferation and a balanced Th1/Th2 response. Importantly, AECD induced Th1 type immunity by augmenting the activation of T subsets (CD4+, CD8+, CD44+) and the induction of IFN-γ in T lymphocytes, especially CTL response and neutralizing antibodies in sera. In addition, AECD maintained the higher levels of CD80, CD40, MHC-II, CD86 on CD11c+ cells and decreased the Treg frequency. Our results suggested that AECD had the potential utility as an polysaccharide adjuvant for FMD vaccines.

Comparison of the structure and immunomodulatory activity of polysaccharides from fresh and dried longan

Abstract The structures and immunomodulatory activities of purified neutral polysaccharides from fresh (FLP) and hot air-dried (DLP) longan were comparatively investigated. FLP was composed of mannose and glucose at a molar ratio of 0.59:1 with average molecular weight of 1.31 × 107 g/mol, and DLP was composed of rhamnose, mannose, glucose and galactose at a molar ratio of 0.2:0.21:1:0.2 with average molecular weight of 1.06 × 107 g/mol. Methylation and NMR data showed that FLP was primarily composed of →6)-α-D-Glcp-(1→, and that DLP was primarily composed of →6)-α-D-Glcp-(1→, →3)-β-D-Glcp-(1→, →3)-β-D-Galp-(1→ and →3)-α-L-Rhap-(1→. FLP and DLP significantly enhanced lymphocyte proliferation, phagocytosis and NO, IL-1β and IL-6 production by macrophages. The drying process increased degree of branching and significantly affected the immunomodulatory activity of longan polysaccharides. DLP exhibited a strong effect on stimulation of the proliferation of lymphocytes and the activation of macrophages. The knowledge of effects of drying process on the structures and bioactivity of longan polysaccharides can aid in illuminating the basis for application of dried longan in the functional foods and medicines production.

Water-Soluble Fiber from Bengkoang (Pachyrhizus erosus (L.) Urban) Tuber Modulates Immune System Activity in Male Mice

Our previous study showed that water-soluble fiber from bengkoang (Pachyrizus erosus (L.) Urban) fiber extract (BFE) and bengkoang fiber fraction B (BFE-B) have phagocytic activity and modulation of cytokine production in vitro. The present study evaluates the immunomodulatory effects of water-soluble fibers BFE and BFE-B on male mice induced by hepatitis B vaccine. Thirty mice were divided into six groups and induced by hepatitis B vaccine intraperitoneally on days 7 and 14. The mice were then treated with BFE, BFE-B, levamisole, or sodium carboxymethyl cellulose for 18 days. At the end of the treatments (day 19), phagocytic activity, lymphocyte proliferation, spleen index, cytokine, and immunoglobulin G (IgG) production were determined. The results showed that the water-soluble fiber treatment could significantly increase phagocytic capacity, nitric oxide production, and spleen index. However, BFE-B could modulate tumor necrosis factor (TNF)-α and interleukin (IL)-10 secretion, BFE demonstrated no such effect on cytokine production. Lymphocyte proliferation assay revealed that treatment with 50 mg/kg body weight (BW) BFE and 50 mg/kg BW BFE-B could significantly enhance lymphocyte proliferation. Treatment with 25 and 50 mg/kg BW BFE-B stimulated IgG production. In conclusion, BFE and BFE-B similarly have immunomodulatory effects on innate immune responses. BFE-B further demonstrated immunomodulatory effects on adaptive immune responses.

Preparation of lentinan-calcium carbonate microspheres and their application as vaccine adjuvants

Adjuvants improve vaccine potency by enhancing immunogenicity and sustaining long-term immune responses. Lentinan (LNT), a β-1,3-glucohexaose with β-1,6-branches, is extracted from the mushroom Lentinus edodes and functions as an effective immunostimulatory drug. Previous studies have demonstrated the adjuvant activity of calcium carbonate (CaCO3) microspheres as well as their use as antigen delivery systems. In this study, we successfully loaded CaCO3 microspheres with LNT and evaluated their physicochemical characteristics prior to the adsorption of ovalbumin. Our experimental results demonstrated that LNT-CaCO3 significantly enhanced lymphocyte proliferation, and boosted the frequency of CD69 + B cells and the ratio of CD4+ to CD8 + T cells in spleen lymphocytes. Moreover, LNT-CaCO3 unexpectedly induced the secretion of IgG and Th-associated cytokines (IL-2, IL-4, IFN-γ, and TNF-α) in immunized mice. Therefore, LNT-CaCO3 microspheres induce robust cellular and humoral immune responses and have potential utility as vaccine delivery systems.

COVID-19 and comorbidities: A role for dipeptidyl peptidase 4 (DPP4) in disease severity?

The coronavirus disease 2019 (COVID-19) pandemic is caused by a novel betacoronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), similar to SARS-CoV and Middle East respiratory syndrome (MERS-CoV), which cause acute respiratory distress syndrome and case fatalities. COVID-19 disease severity is worse in older obese patients with comorbidities such as diabetes, hypertension, cardiovascular disease, and chronic lung disease. Cell binding and entry of betacoronaviruses is via their surface spike glycoprotein; SARS-CoV binds to the metalloprotease angiotensin-converting enzyme 2 (ACE2), MERS-CoV utilizes dipeptidyl peptidase 4 (DPP4), and recent modeling of the structure of SARS-CoV-2 spike glycoprotein predicts that it can interact with human DPP4 in addition to ACE2. DPP4 is a ubiquitous membrane-bound aminopeptidase that circulates in plasma; it is multifunctional with roles in nutrition, metabolism, and immune and endocrine systems. DPP4 activity differentially regulates glucose homeostasis and inflammation via its enzymatic activity and nonenzymatic immunomodulatory effects. The importance of DPP4 for the medical community has been highlighted by the approval of DPP4 inhibitors, or gliptins, for the treatment of type 2 diabetes mellitus. This review discusses the dysregulation of DPP4 in COVID-19 comorbid conditions; DPP4 activity is higher in older individuals and increased plasma DPP4 is a predictor of the onset of metabolic syndrome. DPP4 upregulation may be a determinant of COVID-19 disease severity, which creates interest regarding the use of gliptins in management of COVID-19. Also, knowledge of the chemistry and biology of DPP4 could be utilized to develop novel therapies to block viral entry of some betacoronaviruses, potentially including SARS-CoV-2.

Dietary yeast β-glucan supplementation improves eggshell color and fertile eggs hatchability as well as enhances immune functions in breeder laying hens

The study was conducted to evaluate the effects of dietary yeast β-glucan (YG) on performance and immune functions in breeder hens in a non-challenged setting. A total of 512 43-week-old Hy-Line Brown breeder hens were assigned into four treatments, and fed a basal diet with YG at 0, 50, 100 and 200 mg /kg for 8 weeks, respectively. Results showed that supplementation of YG did not affect production performance, but linearly increased hatchability (P < 0.05). Compared with the control, hens fed with 200 mg/kg YG had improved eggshell color and reduced mortality. Moreover, feeding 200 mg/kg YG significantly (P < 0.05) enhanced lymphocyte proliferation response to LPS, increased the percentage of peripheral blood CD3+ T cells and phytohemagglutinin (PHA) skin response; remarkably down-regulated splenic TLR4, IL-6 and TGF-β mRNA levels while upregulated TLR6 and IFN-γ mRNA levels (P < 0.05). In addition, inclusion of YG at 200 mg/kg considerably promoted the production of serum cytokines, total IgA, and specific antibody titers against BSA, AIV and NDV vaccine (P < 0.05). These results suggested that dietary inclusion of 200 mg/kg YG could improve eggshell color and fertile eggs hatchability and enhance cellular and humoral immune function of breeder hens in a nonchallenged setting without disturbing immune homeostasis.