Oral Adjuvant Research Articles

Immunoadjuvant and Humoral Immune Responses of Garlic (Allium sativum L.) Lectins upon Systemic and Mucosal Administration in BALB/c Mice.

Dietary food components have the ability to affect immune function; following absorption, specifically orally ingested dietary food containing lectins can systemically modulate the immune cells and affect the response to self- and co-administered food antigens. The mannose-binding lectins from garlic (Allium sativum agglutinins; ASAs) were identified as immunodulatory proteins in vitro. The objective of the present study was to assess the immunogenicity and adjuvanticity of garlic agglutinins and to evaluate whether they have adjuvant properties in vivo for a weak antigen ovalbumin (OVA). Garlic lectins (ASA I and ASA II) were administered by intranasal (50 days duration) and intradermal (14 days duration) routes, and the anti-lectin and anti-OVA immune (IgG) responses in the control and test groups of the BALB/c mice were assessed for humoral immunogenicity. Lectins, co-administered with OVA, were examined for lectin-induced anti-OVA IgG response to assess their adjuvant properties. The splenic and thymic indices were evaluated as a measure of immunomodulatory functions. Intradermal administration of ASA I and ASA II had showed a four-fold and two-fold increase in anti-lectin IgG response, respectively, vs. the control on day 14. In the intranasal route, the increases were 3-fold and 2.4-fold for ASA I and ASA II, respectively, on day 50. No decrease in the body weights of animals was noticed; the increases in the spleen and thymus weights, as well as their indices, were significant in the lectin groups. In the adjuvanticity study by intranasal administration, ASA I co-administered with ovalbumin (OVA) induced a remarkable increase in anti-OVA IgG response (~six-fold; p < 0.001) compared to the control, and ASA II induced a four-fold increase vs. the control on day 50. The results indicated that ASA was a potent immunogen which induced mucosal immunogenicity to the antigens that were administered intranasally in BALB/c mice. The observations made of the in vivo study indicate that ASA I has the potential use as an oral and mucosal adjuvant to deliver candidate weak antigens. Further clinical studies in humans are required to confirm its applicability.

Escherichia coli Nissle 1917 Enhances Efficacy of Oral Attenuated Human Rotavirus Vaccine in a Gnotobiotic Piglet Model.

Human rotavirus (HRV) infection is a major cause of viral gastroenteritis in young children worldwide. Current oral vaccines perform poorly in developing countries where efficacious vaccines are needed the most. Therefore, an alternative affordable strategy to enhance efficacy of the current RV vaccines is necessary. This study evaluated the effects of colonization of neonatal gnotobiotic (Gn) pigs with Escherichia coli Nissle (EcN) 1917 and Lacticaseibacillus rhamnosus GG (LGG) probiotics on immunogenicity and protective efficacy of oral attenuated (Att) HRV vaccine. EcN-colonized pigs had reduced virulent HRV (VirHRV) shedding and decreased diarrhea severity compared with the LGG-colonized group. They also had enhanced HRV-specific IgA antibody titers in serum and antibody secreting cell numbers in tissues pre/post VirHRV challenge, HRV-specific IgA antibody titers in intestinal contents, and B-cell subpopulations in tissues post VirHRV challenge. EcN colonization also enhanced T-cell immune response, promoted dendritic cells and NK cell function, reduced production of proinflammatory cytokines/Toll like receptor (TLR), and increased production of immunoregulatory cytokines/TLR expression in various tissues pre/post VirHRV challenge. Thus, EcN probiotic adjuvant with AttHRV vaccine enhances the immunogenicity and protective efficacy of AttHRV to a greater extent than LGG and it can be used as a safe and economical oral vaccine adjuvant.

Successful Treatment of Tinea Capitis Caused by Microsporum canis Using Griseofulvin

Tinea capitis is a scalp and hair follicle dermatophyte infection caused by Trichophyton sp. and Microsporum sp. that more commonly affect children than adults. Microsporum canis is the most common dermatophyte causing tinea capitis reported in Asia that respond well to griseofulvin. We report one case of an 8-year-old child with a history of patchy scaling lesion on the head, alopecia, and pruritus. Dermatological examination revealed multiple scaly erythematous macules, circular shape, sharply marginated, with a diameter of 2?6 cm, along with alopecia in each lesion. KOH preparation, wood lamp examination, trichoscopy, and fungal culture were performed. The diagnosis of tinea capitis grey patch type with an etiology of Microsporum canis was established. The patient was significantly improved clinically and mycologically with four weeks course of oral griseofulvin and adjuvant treatment using ketoconazole 2% scalp solution. Griseofulvin is effective to treat tinea capitis caused by Microsporum sp. Comprehensive examination in tinea capitis is necessary to confirm the diagnosis and the etiology as well to determine the best treatment for the case

A disordered region retains the full protease inhibitor activity and the capacity to induce CD8+ T cells in vivo of the oral vaccine adjuvant U-Omp19

U-Omp19 is a bacterial protease inhibitor from Brucella abortus that inhibits gastrointestinal and lysosomal proteases, enhancing the half-life and immunogenicity of co-delivered antigens. U-Omp19 is a novel adjuvant that is in preclinical development with various vaccine candidates. However, the molecular mechanisms by which it exerts these functions and the structural elements responsible for these activities remain unknown. In this work, a structural, biochemical, and functional characterization of U-Omp19 is presented. Dynamic features of U-Omp19 in solution by NMR and the crystal structure of its C-terminal domain are described. The protein consists of a compact C-terminal beta-barrel domain and a flexible N-terminal domain. The latter domain behaves as an intrinsically disordered protein and retains the full protease inhibitor activity against pancreatic elastase, papain and pepsin. This domain also retains the capacity to induce CD8+ T cells in vivo of U-Omp19. This information may lead to future rationale vaccine designs using U-Omp19 as an adjuvant to deliver other proteins or peptides in oral formulations against infectious diseases, as well as to design strategies to incorporate modifications in its structure that may improve its adjuvanticity.

Mesoporous silica nano-adjuvant triggers pro-inflammatory responses in Caco-2/peripheral blood mononuclear cell (PBMC) co-cultures.

The aim of this study was to evaluate the cytotoxicity and immune-stimulatory effect of Mesoporous silica nanoparticle (MSN) Nano-adjuvant on pro-inflammatory cytokines and pattern recognition receptors (PRR) genes expression in Caco-2/PBMC co-culture model. MSNs were synthesized and characterized by scanning electron microscope (SEM), Brunauer Emmett Teller (BET) and Barrett Joyner Halenda (BJH) techniques. The BET specific surface area of MSNs was around 947 m2/g and the total pore volume and average pore diameter were 1.5 cm3/g and 8.01 nm, respectively. At the concentration of 10 µg/mL, MSN showed a low and time-dependent cytotoxicity on Caco-2 cells, while no cytotoxic effect was observed for 0.1 and 1 µg/mL concentrations after 24, 48 and 72 h. The expression of pro-inflammatory cytokines genes (IL-1, IL-8 and TNF-α) in co-cultures treated with different concentrations of MSN showed a dose-dependent significant increase up to 17.44, 2.722 and 4.34 folds, respectively, while the expression augmentation of IL-1 gene was significantly higher than the others. This indicates slight stimulation of intestinal inflammation. Different concentrations of MSN significantly increased TLR4 and NOD2 expression to 4.14 and 2.14 folds, respectively. NOD1 was not affected significantly. It can be concluded that MSN might increase protective immune responses against antigens as a vaccine adjuvant candidate. It seems that stimulation of TNF-α, IL-1, and IL-8 expression in enterocytes probably transpires through the agonistic activity of MSN for TLRs including TLR4, while NOD2-associated signaling pathways are also involved. This study provides an overall picture of MSN as a novel and potent oral adjuvant for mucosal immunity.

Adjuvant Effect of Orally Applied Preparations Containing Non-Digestible Polysaccharides on Influenza Vaccination in Healthy Seniors: A Double-Blind, Randomised, Controlled Pilot Trial.

Senior individuals can suffer from immunosenescence and novel strategies to bolster the immune response could contribute to healthy ageing. In this double-blind, randomised, controlled pilot trial, we investigated the ability of non-digestible polysaccharide (NPS) preparations to enhance the immune response in a human vaccination model. In total, 239 subjects (aged 50–79 years) were randomised to consume one of five different NPS (yeast β-glucan (YBG), shiitake β-glucan (SBG), oat β-glucan (OBG), arabinoxylan (AX), bacterial exopolysaccharide (EPS)) or control (CTRL) product daily for five weeks. After two weeks of intervention, subjects were vaccinated with seasonal influenza vaccine. The post-vaccination increases in haemagglutination inhibition antibody titres and seroprotection rate against the influenza strains were non-significantly enhanced in the NPS intervention groups compared to CTRL. Specifically, a trend towards a higher mean log2 fold increase was observed in the AX group (uncorrected p = 0.074) combined with a trend for an increased seroprotection rate, AX group (48.7%) compared to CTRL (25.6%) (uncorrected p = 0.057), for the influenza A H1N1 strain. Subjects consuming AX also had a reduced incidence of common colds compared to CTRL (1 vs. 8; p = 0.029 in Fisher exact test). No adverse effects of NPS consumption were reported. The findings of this pilot study warrant further research to study AX as an oral adjuvant to support vaccine efficacy.

Type II NKT Cell Agonist, Sulfatide, Is an Effective Adjuvant for Oral Heat-Killed Cholera Vaccines.

Oral vaccination has the potential to offer a safer and more efficacious approach for protection against enteric pathogens than injection-based approaches, especially in developing countries. One key advantage is the potential to induce intestinal immune responses in addition to systemic immunity. In general, antigen delivery via the oral route triggers weak immune responses or immunological tolerance. The effectiveness of oral vaccination can be improved by co-administering adjuvants. However, a major challenge is the absence of potent and safe oral adjuvants for clinical application. Here, the Type II NKT cell activator sulfatide is shown for the first time to be an effective oral adjuvant for Vibrio cholerae vaccine antigens in a mouse model. Specifically, administration of sulfatide with the oral cholera vaccine Dukoral® resulted in enhancement of intestinal antigen-specific IgA in addition to Th1 and Th17 immune responses. In summary, sulfatide is a promising adjuvant for inclusion in an oral cholera vaccine and our data further support the potential of adjuvants targeting NKT cells in new vaccine strategies.

An Outer Membrane Vesicle-Adjuvanted Oral Vaccine Protects Against Lethal, Oral Salmonella Infection.

Non-typhoidal salmonellosis, caused by Salmonella enterica serovar Typhimurium is a common fecal-oral disease characterized by mild gastrointestinal distress resulting in diarrhea, chills, fever, abdominal cramps, head and body aches, nausea, and vomiting. Increasing incidences of antibiotic resistant invasive non-typhoidal Salmonella infections makes this a global threat requiring novel treatment strategies including next-generation vaccines. The goal of the current study was to formulate a novel vaccine platform against Salmonella infection that could be delivered orally. To accomplish this, we created a Salmonella-specific vaccine adjuvanted with Burkholderia pseudomallei outer membrane vesicles (OMVs). We show that adding OMVs to a heat-killed oral Salmonella vaccine (HKST + OMVs) protects against a lethal, oral challenge with Salmonella. Further, we show that opsonizing anti-Salmonella antibodies are induced in response to immunization and that CD4 T cells and B cells can be induced when OMVs are used as the oral adjuvant. This study represents a novel oral vaccine approach to combatting the increasing problem of invasive Salmonella infections.

Oral vaccination of Nile tilapia (Oreochromis niloticus) against francisellosis elevates specific antibody titres in serum and mucus

Although Nile tilapia (Oreochromis niloticus) is a well-established aquaculture species globally, there are a limited number of commercial vaccines available or are used for this species. The majority of diseases affecting farmed tilapia are bacterial, with antibiotics frequently used to treat fish. The current study was performed to optimise the use of mucosal vaccines for tilapia by adapting an existing bacterin vaccine against Francisella noatunensis subsp. orientalis (Fno) as a proof of concept. This vaccine has previously provided excellent protection by injection, however, the preference for tilapia farmers would be to vaccinate fish by immersion or orally, due to the lower cost and ease of application. These vaccination routes, however, are often less efficacious probably due to the lack of adjuvants in immersion and oral vaccines. The aims of this study, therefore, were to optimise the formulation and dose of the Fno vaccine with mucosal adjuvants for oral and immersion delivery. Tilapia fry (av. 6 g) were given three concentrations (high, medium, low; i.e. 1×109, 1×108 and 1×107 CFU mL-1) of antigen combined with the oral adjuvant by oral gavage, to optimise the dose needed to induce an immune response to Fno, and the immune response obtained compared with fish vaccinated by immersion (with and without an immersion adjuvant). Fry were boosted by the same route at 420 degree days (DD), and samples (serum, mucus ) taken at 840 DD for specific antibody responses measured by ELISA and western blotting. Specific IgM titres were significantly elevated in serum and mucus of fish given the high dose adjuvanted vaccine by gavage. In addition, by western blotting with serum, a significant immunogenic reaction was evident between 20 and 37 kDa in the fish given the high dose oral vaccine by gavage. As protection against Fno provided by the injection vaccine was correlated with specific antibody responses these findings suggest the oral vaccine also has potential to provide protection. Further studies are needed to optimise delivery of the vaccine via feed.

Utilization of apnea-hypopnea index as a novel predictive factor for difficult mask ventilation in the Chinese population under general anesthesia

PurposeDifficult mask ventilation (DMV) is a potentially life-threatening situation that can arise during anesthesia. However, most clinical predictors of DMV are based on European and US populations. On the other hand, most predictive models consist of multiple factors and complicated assessments. Since obstructive sleep apnea (OSA) is among the most important risk factors associated with DMV, the apnea-hypopnea index (AHI) may play an important role in determining patient risk.The purpose of this study was to investigate the relationship between DMV and AHI, and to determine preoperative risk factors for DMV in Chinese patients.MethodsA prospective cohort trial enrolled patients scheduled for elective surgery. After obtaining informed consent, patient demographic information was collected, and patients were tested with pre-operative polysomnography. The anesthesiologist who managed the airway graded the mask ventilation. The difficult mask ventilation was defined as the mask ventilation provided by an unassisted anesthesiologist without oral airway or other adjuvant. A logistic regression model was used to analyze the association between AHI and DMV.ResultsA total of 159 patients were analyzed. For both primary and secondary outcomes, the unadjusted and adjusted odds ratio for DMV showed significant increases by 5 AHI units. AHI, age, and the Mallampati classification were found to be independent predictive factors for DMV.ConclusionsAHI is associated with DMV as a novel independent risk factor in Chinese patients. Along with age and Mallampati classification, AHI should be included in establishing a superior predictive strategy for DMV screening.Trial registrationChinese Clinical Trial Registry ChiCTR-DDD-17013076

Assessing the efficiency of SBA-15 as a nanocarrier for diphtheria anatoxin

Abstract SBA-15 ordered mesoporous silica can be considered a promising inorganic nanocarrier with emerging potential as an oral vaccine adjuvant. In this study, we investigated its application in the encapsulation of the diphtheria anatoxin (dANA). We observed a considerable preservation of dANA secondary and tertiary structures, even after the drying process by means of Circular Dichroism (CD) and fluorescence spectroscopies. Antigen loading was assessed at a number of different ratios of adjuvant-to-antigen using a combination of nitrogen adsorption porosimetry and Small Angle X-ray Scattering (SAXS). Our data showed that the mass ratio of 1:10 (dANA:SBA-15) is recommended for total encapsulation of dANA in the mesopores, considering that at this relative mass concentration antigen clustering was avoided, which is deleterious effect for immunization purposes. dANA release in mimetic intestine fluid, at a pH equal to 6.8, was followed by in-situ SAXS measurements and shown to be slow, being more pronounced after 6 h and continuous up to 35 h. Finally, the immunogenic complex was tested in isogenic Balb C mice by oral and subcutaneous immunization routes, including a comparison with the only permitted adjuvant for human use, aluminum hydroxide. A higher antibody titer was obtained by subcutaneous and oral administration routes using SBA-15 as the vehicle of dANA, compared with the conventional aluminum hydroxide, demonstrating the viability to use this ordered mesoporous silica in the formulation of oral vaccines, as already proved for the Virus Like Particles (VLP) Hepatitis B (HBsAg) case.

Effect of Adding Losartan to Bevacizumab for Treating Diabetic Macular Edema.

Introduction Diabetic retinopathy is the most common cause of visual loss and blindness in the age group of 20 to 64 years. This study aimed to evaluate the efficacy of oral Losartan adjuvant therapy in combination with intravitreal injection of Bevacizumab in the treatment of diabetic macular edema. Methods In this randomized clinical trial, 61 eyes of 47 patients with normal blood pressure and diabetic macular edema and nonproliferative diabetic retinopathy were studied. Patients were randomly divided into Losartan (n = 33) and control (n = 28) groups. All patients received 3–6 intravitreal injections of Bevacizumab over 6 months. General examination including blood pressure and glycosylated hemoglobin measurements were performed in all patients. Complete ophthalmologic examination and macular OCT were performed at the first, third, and sixth months of treatment in all patients. Results The mean age of the patients studied was 57.1 ± 7.4 years and 37.7% of the patients were male. There was no significant difference between the two groups in terms of initial visual acuity, central macular thickness, and frequency of injections. There was no significant difference in visual acuity and central macular thickness between the two groups at the first, third, and sixth months of treatment. Age, frequency of injection, and initial macular thickness less than 450 microns were effective in patients' final visual acuity. Conclusion Short-term adjuvant treatment with Losartan in patients with diabetic macular edema and nonproliferative diabetic retinopathy has no greater effect than the standard treatment.

Potential of the Escherichia coli LT(R192G/L211A) toxoid as a mucosal adjuvant for rainbow trout (Oncorhynchus mykiss)

Oral vaccines are highly demanded by aquaculture sector that requires alternatives to injectable vaccines, involving fish handling, stress-related immunosuppression and mortalities. However, most previous attempts to obtain effective oral vaccines have failed due to a restricted tolerance mechanisms in intestine, whose mucosa is at the frontline of antigen encounter and has to balance the equilibrium between tolerance and immunity in a microbe-rich environment. Thus, the search for oral adjuvants that could augment immune responses triggered by antigens allowing them to circumvent intestinal tolerance is of great relevance. The present work focuses on the adjuvant potential of the Escherichia coli LT(R192G/L211A) toxoid (dmLT). To undertake an initial screening of the potential that dmLT has as an oral adjuvant in rainbow trout (Oncorhynchus mykiss), we have analyzed its transcriptional effects alone or in combination with Aeromonas salmonicida subsp. salmonicida or viral hemorrhagic septicemia virus (VHSV) on rainbow trout intestinal epithelial cell line RTgutGC and gut explants. Our results show that although dmLT provoked no significant effects by itself, it increased the transcription of pro-inflammatory cytokines and antimicrobial genes induced by the bacteria. In contrast, when combined with VHSV, dmLT only increased the transcription of Mx and the intracellular adhesion molecule 1 (ICAM1). Therefore, the protocol designed is an effective method to initially evaluate the effects of potential oral adjuvants, and points to dmLT as an effective adjuvant for oral antibacterial vaccines.

U-Omp19 from Brucella abortus increases dmLT immunogenicity and improves protection against Escherichia coli heat-labile toxin (LT) oral challenge

Acute diarrhea disease caused by bacterial infections is a major global health problem. Enterotoxigenic Escherichia coli (ETEC) is one of the top causes of diarrhea-associated morbidity and mortality in young children and travelers to low-income countries. There are currently no licensed vaccines for ETEC. Induction of immunity at the site of entry of the bacteria is key to prevent infection. Current approaches to ETEC vaccines include a less toxic mutant form of E. coli heat-labile toxin (double-mutant heat-labile enterotoxin -dmLT-) with both antigenic and immunostimulatory properties. U-Omp19 is a protease inhibitor from Brucella spp. with immunostimulatory properties that has been used as oral adjuvant. In this work, we use U-Omp19 as adjuvant in an oral vaccine formulation against ETEC containing dmLT in outbred and inbred mice. To evaluate antigen dose sparing by U-Omp19 three different immunization protocols with three different doses of dmLT were evaluated. We demonstrated that U-Omp19 co-delivery increases anti-LT IgA in feces using a mid-dose of dmLT following a prime-boost protocol (after one or two boosts). Oral immunization with U-Omp19 induced protection against LT challenge when co-formulated with dmLT in CD-1 and BALB/c mice. Indeed, there was a significant increase in anti-LT IgG and IgA avidity after a single oral administration of dmLT plus U-Omp19 in comparison with dmLT delivered alone. Interestingly, sera from dmLT plus U-Omp19 vaccinated mice significantly neutralize LT effect on intestine inflammation in vivo compared with sera from the group immunized with dmLT alone. These results demonstrate the adjuvant capacity of U-Omp19 to increase dmLT immunogenicity by the oral route and support its use in an oral subunit vaccine formulation against ETEC.

KEMAMPUAN POLISAKARIDA MANNAN SEBAGAI ORAL ADJUVAN VAKSIN AVIAN INFLUENZA PADA AYAM BROILER

Polysaccharides contain mannan (PM) from palm kernel meal (PKM) potential as leader pathogen microorganism and enhancing the immune responses. The objective of the study was to evaluate efficacy of PM as oral adjuvant in increasing AI H5N1 antibody titer and immunoglobulin A (IgA) in serum of broiler thirty chickens age 1 - 6 weeks were divided onto five groups and assigned randomly to five vaccine treatments i.e : un-vaccinated birds (R0A), birds vaccinated with antigen H5N1 + 0 µg PM (R0B), birds vaccinated with antigen H5N1 + 50 µg PM (R1), birds vaccinated with antigen H5N1 + 100 µg PM (R2) and birds vaccinated with antigen H5N1 + 200 µg PM (R3). The results showed the treatment did not reduce broiler body weight (PM is not toxic). AI H5N1 antibody titer increased significantly (P0.05) one week after the first vaccination, serum IgA of broiler also increased significantly (P0.05) two weeks after the second vaccination. R3 treatment (200 μg PM) produce higher HI antibody titer ≤ 5 log2 and serum IgA 1.6 fold higher compared with those of broiler received R0A and R0B. It can be concluded that PM can increase the immune response in broiler chickens and can be used as an adjuvant for inactive AI vaccine.

Oral adjuvant therapy for colorectal cancer: recent developments and future targets.

Colorectal cancer is considered the third most frequent malignant neoplasm occurring in both men and women worldwide. Most approaches that have been used to fight and treat this type of malignancy are either invasive or nonselective. Noninvasive therapy using oral route can increase patient compliance and reduce treatment costs. Innovative measures such as use of nanotechnology and theranostic systems have been initiated in the oral therapy, which has been proven to be greatly advantageous in decreasing side effects, improving detection and diagnoses. This manuscript investigates recent innovative and novel therapeutic approaches through oral route and potential targets in the treatment of colorectal cancer.

Effectiveness of omega-3 fatty acid administration on completion rate of adjuvant chemotherapy for biliary tract cancer: study protocol for a single-centre, open-label, single-arm, historically controlled study

IntroductionMultimodal treatment prolongs the survival of patients with biliary tract cancer (BTC). However, the chemotherapy choices for this disease are few, and completing each chemotherapy session is important. Adjuvant chemotherapy...

2'-Fluoro-c-di-GMP as an oral vaccine adjuvant.

Bis-(3′–5′)-cyclic dimeric 2′-deoxy-2′-fluoroguanosine monophosphate (2′-F-c-di-GMP) was synthesized through the modified H-phosphonate chemistry. Oral immunization of C57BL/6 mice with Helicobacter pylori cell-free sonicate extract adjuvanted with 2′-F-c-di-GMP led to the production of antigen-specific antibodies in feces and sera, and lowered bacterial counts in the stomach upon post-vaccination infections in immunized mice. Similarly, oral vaccination of BALB/c mice with flagillin proteins from Clostridium difficile and Listeria monocytogenes adjuvanted with 2′-F-c-di-GMP led to production of antigen-specific antibodies both systemically and mucosally. The adjuvanticity of 2′-F-c-di-GMP is associated with the enhanced induction of interferon γ. These results demonstrated the excellent oral adjuvanticity of 2′-F-c-di-GMP.

Immunopotentiating effect of Inonotus obliquus fermentation products administered at vaccination in chickens

Vaccination is an important approach for the control of avian viral diseases. The aim of this study was to evaluate the immune-potentiating effect of oral administration of Inonotus obliquus fermentation products (IOFP) at vaccination in chickens. In total, 120 one-day-old specific-pathogen-free chickens were randomly assigned to six groups: groups 1 to 3 were vaccinated with Newcastle disease virus (NDV) LaSota live vaccine via intranasal and eye-dropped route at seven days of age, and boosted two weeks later. Before each immunization, chickens in groups 1 and 2 were orally administered 0.8% IOFP and 0.2% astragalus polysaccharide (APS) in their diets, respectively, for seven consecutive days and group 3 was fed with commercial diet. At the same time, group 4, 5 and 6 were inoculated in the same manner with PBS and fed with commercial diet, containing 0.8% IOFP and 0.2% APS diet, respectively, as negative controls. At 0, 7, 14, 21, 28, and 35 days post-inoculation (dpi) firstly, the temporal changes in serum Newcastle disease hemagglutination inhibition (HI) and neutralizing antibody titers were determined. Meanwhile, proliferations of peripheral blood mononuclear cells (PBMCs) isolated from each group in response to concanavalin A stimulation and the expression levels of Th1-type (IFN-γ) and Th2-type (IL-4) cytokines were determined by 3-(4,5-Dimethylthiazol-2-yl) −2,5-diphenyltetrazolium bromide, and ELISA methods. On days 0, 14 and 28 after the first vaccination, the percentages of CD3+, CD3+CD8+, and CD3+CD4+ T lymphocytes were detected by flow cytometry. At 35 dpi, a challenge test was carried out and protective efficacy was determined. Results showed that oral administration of IOFP could significantly enhance ND HI and neutralizing antibody titers, proliferation of PBMCs, proportions of CD3+, CD3+CD8+, and CD3+CD4+ T lymphocytes, as well as the ratio of Th1/Th2, and all of these values were superior to those seen with APS as a positive control, and other groups. Therefore, IOFP possesses significant immune-potentiating properties in chickens and may be a more economical and convenient oral adjuvant to improve vaccination in avian species.

Probiotic bacteria cell walls stimulate the activity of the intestinal epithelial cells and macrophage functionality.

The effect of oral administration of probiotic bacteria cell walls (PBCWs) in the stimulation of the immune system in healthy BALB/c mice was evaluated. We focused our investigation mainly on intestinal epithelial cells (IECs) which are essential for coordinating an adequate mucosal immune response and on the functionality of macrophages. The probiotic bacteria and their cell walls were able to stimulate the IECs exhibiting an important activation and cytokine releases. Supplementation with PBCWs promoted macrophage activation from peritoneum and spleen, indicating that the PBCWs oral administration was able to improve the functionality of the macrophages. In addition, the PBCWs increased immunoglobulin A (IgA)-producing cells in the gut lamina propria in a similar way to probiotic bacteria, but this supplementation did not have an effect on the population of goblet cells in the small intestine epithelium. These results indicate that the probiotic bacteria and their cell walls have an important immunoregulatory effect on the IECs without altering the homeostatic environment but with an increase in IgA+ producing cells and in the innate immune cells, mainly those distant from the gut such as spleen and peritoneum. These findings about the capacity of the cell walls from probiotic bacteria to stimulate key cells, such as IECs and macrophages, and to improve the functioning of the immune system, suggest that those structures could be applied as a new oral adjuvant.