The role of helper T cell products in mouse B cell differentiation and isotype regulation

Immune Response Profiling of Cocktails of Brugia malayi Vaccine Candidates DIM-1, Calponin and Troponin 1 in BALB/c Mice

PURPOSE

In search of a vaccine for the control of human lymphatic filariasis (LF) caused by Wuchereria bancrofti, Brugia malayi and B. timori, we identified three parasite-specific potential candidates: the disorganized muscle protein-1 (D), calponin (C) and troponin 1 (T) in B. malayi adult worm. In the present study, we investigated the immune response profile of the cocktails of the recombinant D, T and C proteins.

METHODS

Groups of BALB/c mice were immunized with individual rproteins or their cocktails DT, TC, DC and DTC, and the immunogen-specific IgG and its subclasses and IgE were determined. Cells from the immunized animals were challenged in vitro with the respective rproteins and cocktails and the release of nitric oxide (NO) from macrophages and Th1 and Th2 cytokines from splenocytes were determined.

RESULTS

Among the immunized groups, DTC elicited comparatively a stronger response which included augmented release of NO, Th1 (IL-1β, IL-2, IFN-γ and TNF-α) and Th2 (IL-4, IL-6, IL-10 and TGF-β) cytokines, and increased levels of immunogen-specific IgG, IgG1 and IgG2b and low levels of immunogen-specific IgG2a and IgE and the Th2 cytokine IL-13.

CONCLUSION

Immune responses that play important role in host protection were elicited strongly by DTC cocktail compared to the individual rproteins or DT, TC and DC cocktails. The findings provide a sound rationale for further studies on DTC cocktail as a vaccine candidate for the control of LF.

Effect of NO2 exposure on airway inflammation and oxidative stress in asthmatic mice

Nitrogen dioxide (NO₂) is a widespread air pollutant. Epidemiological evidence indicates that NO₂ is associated with an increase of incidence rate and mortality of asthma, but its mechanism is still unclear. In this study, we exposed mice to NO₂ (5 ppm, 4 h per day for 30 days) intermittently to investigate the development and potential toxicological mechanisms of allergic asthma. We randomly assigned 60 male Balb/c mice to four groups: saline control, ovalbumin (OVA) sensitization, NO₂ alone, and OVA+NO₂ groups. The involved mechanisms were found from the perspective of airway inflammation and oxidative stress. The results showed that NO₂ exposure could aggravate lung inflammation in asthmatic mice, and airway remodeling was characterized by significant thickening of the airway wall and infiltration of inflammatory cells. Moreover, NO₂ would aggravate the airway hyperresponsiveness (AHR), which is characterized by significantly elevated inspiratory resistance (Ri) and expiratory resistance (Re), as well as decreased dynamic lung compliance (Cldyn). In addition, NO₂ exposure promoted pro-inflammatory cytokines (IL-6 and TNF-α) and serum immunoglobulin (IgE) production. The imbalance of Th1/Th2 cell differentiation (IL-4 increased, IFN-γ reduced, IL-4/IFN-γ significantly increased) played a key role in the inflammatory response of asthma under NO₂ exposure. In a nutshell, NO₂ exposure could promote allergic airway inflammation and increase asthma susceptibility. The levels of ROS and MDA among asthmatic mice exposed to NO₂ increased significantly, while GSH levels sharply decreased. These findings may provide better toxicological evidence for the mechanisms of allergic asthma risk due to NO₂ exposure.

Interaction of high temperature and NO2 exposure on asthma risk: In vivo experimental evidence of inflammation and oxidative stress

Allergic asthma is a complicated respiratory disease with many concerns. Mounting epidemiological evidence linked temperature (T) and NO2 with allergic asthma, yet toxicological studies remain scarce. We conducted an in vivo study to explore toxicological evidence in T-NO2 interaction on allergic asthma, to investigate underlying toxicological mechanisms. 90 male Balb/c mice were randomly and equally divided into 6 groups including saline control, ovalbumin (OVA)-sensitized, OVA + 35 °C, OVA + NO2, OVA + 35 °C + NO2, and OVA + 35 °C + NO2 + capsazepine (CZP), adopting treatment for 38 days. We measured pulmonary functions of inspiratory resistance (Ri), expiratory resistance (Re) and airway compliance (Cldyn), serum protein biomarkers, indexes of pulmonary inflammation, histopathological changes and protective effects of CZP. Airway hyperresponsiveness (AHR) was aggravated by high T (35 °C) and NO2 (5 ppm) co-exposure with a series of aggravating asthmatic symptoms including airway wall thickening, lumen stenosis, goblet cell proliferation, mucus hypersecretion, and subepithelial fibrotic hyperplasia, providing evidence in the toxicological impact of high T-NO2 interaction. The biomarkers of serum immune functions (Total-IgE, OVA-sIgE and IL-4), pro-inflammation (IL-6 and TNF-α), oxidative stress cytokines (8-OHdG, ROS and MDA), airway resistance (Ri and Re), and TRPV1 expression significantly increased, while IFN-γ, GSH and airway compliance (Cldyn) significantly decreased with co-exposure to high T and NO2. We observed that CZP addition significantly ameliorated these toxicological effects and biomarker levels induced by heat-NO2 interaction. Our results suggest a toxicity of heat-NO2 interaction on asthma with clear mechanisms, which can be ameliorated by CZP, indicating that both oxidative stress and TRPV1 expression may be primarily responsible for asthma of heat-NO2-induced toxicity.

Dupilumab: Advances in the off-label usage of IL4/IL13 antagonist in dermatoses

Type 2 immune response refers to a complicated series of immune responses characterized by Th2 polarization and Th2 cytokines secretion. The IgE secretion, airway hypersensitivity, and effector cell recruitment (eosinophils, mast cells, basophils) in skin lesion and peripheral blood stream could be upregulated during the activation of type 2 immune response. Th1/Th2 ratio, also referred as Th1/Th2 balance, represent the T lymphocytes immune pattern to a certain degree: Th1-dominated responses are often involved in intracellular infections (e.g., mycobacterium tuberculosis) and autoimmune diseases (e.g., Graves' disease) while Th2-dominated responses are involved in allergic conditions (e.g., atopic dermatitis, eczema), IgE mediated diseases (e.g., urticaria), and fibrotic dermatoses (e.g., keloids). Dupilumab, as one of the most widely applied Th2 cytokine inhibitors, could block the bioactivity of IL-14/IL-13 via competitively binding to the common IL-4Rα subunit shared by IL-4 and IL-13 receptors. In addition to the direct inhibition of type 2 response, dupilumab is also effective in autoimmune and some infectious skin diseases through indirect regulation of type 1 immune response. The pathological mechanism of Th2 responses and advanced clinical application of dupilumab in skin diseases will be summarized and discussed in the review.

An mRNA-based rabies vaccine induces strong protective immune responses in mice and dogs

Rabies is a lethal zoonotic disease that is mainly caused by the rabies virus (RABV). Although effective vaccines have long existed, current vaccines take both time and cost to produce. Messenger RNA (mRNA) technology is an emergent vaccine platform that supports rapid vaccine development on a large scale. Here, an optimized mRNA vaccine construct (LVRNA001) expressing rabies virus glycoprotein (RABV-G) was developed in vitro and then evaluated in vivo for its immunogenicity and protective capacity in mice and dogs. LVRNA001 induced neutralizing antibody production and a strong Th1 cellular immune response in mice. In both mice and dogs, LVRNA001 provided protection against challenge with 50-fold lethal dose 50 (LD50) of RABV. With regards to protective efficiency, an extended dosing interval (14 days) induced greater antibody production than 3- or 7-day intervals in mice. Finally, post-exposure immunization against RABV was performed to evaluate the survival rates of dogs receiving two 25 μg doses of LVRNA001 vs. five doses of inactivated vaccine over the course of three months. Survival rate in the LVRNA001 group was 100%, whereas survival rate in the inactivated vaccine control group was only 33.33%. In conclusion, these results demonstrated that LVRNA001 induced strong protective immune responses in mice and dogs, which provides a new and promising prophylactic strategy for rabies.

Canine Cytokines Profile in an Endemic Region of L. infantum: Related Factors

Canine leishmaniosis is caused by infection with parasite Leishmania infantum, which are transmitted by sandflies Phlebotomus. Canine leishmaniosis is an endemic disease in the Mediterranean region. The immune response could vary between hosts and determines the severity of the disease and clinical features. The aim of this study was to analyze the serum levels of cytokines TNF-α, IFN-γ, IL-2, IL-6, and IL-8, which are related to the activation of Th1 or Th2 immune responses in dogs living in the L. infantum endemic region. Moreover, we intend to relate and correlate these levels with different factors, such as sex, age, diet, lifestyle, and breed. Epidemiological data and serum were recovered for seventy-eight dogs, and serum levels of cytokines described previously were analyzed by using the ELISA method. The results showed differences in serum levels of IFN-γ, IL-2, and IL-8 between breeds. The lifestyle also affected serum levels of IL-2. The main conclusion of this study is that Ibizan hounds and crossbred dogs have a serological profile of cytokines that seems to indicate certain protections against infection by L. infantum compared to boxer and purebred breeds.

Novel Oxime-Derivatized Synthetic Triterpene Glycosides as Potent Saponin Vaccine Adjuvants

Vaccine adjuvants are key for optimal vaccine efficacy, increasing the immunogenicity of the antigen and potentiating the immune response. Saponin adjuvants such as the carbohydrate-based QS-21 natural product are among the most promising candidates in vaccine formulations, but suffer from inherent drawbacks that have hampered their use and approval as stand-alone adjuvants. Despite the recent development of synthetic derivatives with improved properties, their full potential has not yet been reached, allowing the prospect of discovering further optimized saponin variants with higher potency. Herein, we have designed, chemically synthesized, and immunologically evaluated novel oxime-derivatized saponin adjuvants with targeted structural modifications at key triterpene functionalities. The resulting analogues have revealed important findings into saponin structure-activity relationships, including adjuvant mechanistic insights, and have shown superior adjuvant activity in terms of significantly increased antibody response augmentation compared to our previous saponin leads. These newly identified saponin oximes emerge as highly promising synthetic adjuvants for further preclinical development towards potential next generation immunotherapeutics for future vaccine applications.

Evaluation of allergenicity of cow milk treated with enzymatic hydrolysis through a mouse model of allergy

Cow milk (CM) allergy is a worldwide concern. Currently, few studies have been performed on the immunoreactivity of CM and fewer still on the antigenicity of CM in vivo and in vitro. In this study, we assessed the potential allergenicity of enzymatically hydrolyzed CM using in vitro ELISA and oral sensitization and challenge of BALB/c mice. Alcalase-, Protamex-, and Flavourzyme-treated CM (all from Novozymes) diminished IgE binding capacity, with greatest reductions of 56.31%, 50.62%, and 56.45%, respectively. Allergic symptoms and levels of total IgG1 were reduced, and allergic inflammation of the lung, jejunum, and spleen was relieved. Moreover, the numbers of CD8+ T and B220+ cells decreased, and the balance of CD4+ T/CD8+ T cells was effectively regulated. These findings suggest that the potential allergenicity of CM was reduced by enzymatic hydrolysis, and our research will lay a solid foundation for developing high-quality hypoallergenic CM products.

Synthesis of Azido-Globo H Analogs for Immunogenicity Evaluation

Globo H (GH) is a tumor-associated carbohydrate antigen (TACA), and GH conjugations have been evaluated as potential cancer vaccines. However, like all carbohydrate-based vaccines, low immunogenicity is a major issue. Modifications of the TACA increase its immunogenicity, but the systemic modification on GH is challenging and the synthesis is cumbersome. In this study, we synthesized several azido-GH analogs for evaluation, using galactose oxidase to selectively oxidize C6-OH of the terminal galactose or N-acetylgalactosamine on lactose, Gb3, Gb4, and SSEA3 into C6 aldehyde, which was then transformed chemically to the azido group. The azido-derivatives were further glycosylated to azido-GH analogs by glycosyltransferases coupled with sugar nucleotide regeneration. These azido-GH analogs and native GH were conjugated to diphtheria toxoid cross-reactive material CRM197 for vaccination with C34 adjuvant in mice. Glycan array analysis of antisera indicated that the azido-GH glycoconjugate with azide at Gal-C6 of Lac (1-CRM197) elicited the highest antibody response not only to GH, SSEA3, and SSEA4, which share the common SSEA3 epitope, but also to MCF-7 cancer cells, which express these Globo-series glycans.

Immunomodulatory Effects of Curcumin in Rheumatoid Arthritis: Evidence from Molecular Mechanisms to Clinical Outcomes

Rheumatoid arthritis (RA) is a chronic immune-mediated inflammatory disorder characterized by the destruction of the joint and bone resorption. The production of pro-inflammatory cytokines and chemokines, dysregulated functions of three important subtypes of T helper (T_H) cells including T_H1, T_H17, and regulator T (Treg) cells are major causes of the initiation and development of RA. Moreover, B cells as a source of the production of several autoantibodies play key roles in the pathogenesis of RA. The last decades have seen increasingly rapid advances in the field of immunopharmacology using natural origin compounds for the management of various inflammatory diseases. Curcumin, a main active polyphenol compound isolated from turmeric, curcuma longa, possesses a wide range of pharmacologic properties for the treatment of several diseases. This review comprehensively will assess beneficial immunomodulatory effects of curcumin on the production of pro-inflammatory cytokines and also dysregulated functions of immune cells including T_H1, T_H17, Treg, and B cells in RA. We also seek the clinical efficacy of curcumin for the treatment of RA in several recent clinical trials. In conclusion, curcumin has been found to ameliorate RA complications through modulating inflammatory and autoreactive responses in immune cells and synovial fibroblast cells via inhibiting the expression or function of pro-inflammatory mediators, such as nuclear factor-κB (NF-κB), activated protein-1 (AP-1), and mitogen-activated protein kinases (MAPKs). Of note, curcumin treatment without any adverse effects can attenuate the clinical symptoms of RA patients and, therefore, has therapeutic potential for the treatment of the diseases.

Immunogenicity of a new allergoid from Felis domesticus

BACKGROUND

The chemical modification of allergens with glutaraldehyde improves safety while maintaining clinical efficacy, which permits the administration of higher doses of immunotherapy, reducing the risk of adverse reactions. The aim of this study is to evaluate the immunogenic capacity of a new cat dander polymer by immunizing mice and quantifying immunoglobulins in serum, in comparison with the non-modified allergen.

METHODS

The study consists of the immunization of three mice groups with the polymerized and the native extract, together with a negative control group. The immunoglobulin levels in serum have been measured by indirect ELISA. By means of the non-parametric Mann-Whitney U test, it was determined if there were significant differences in the values of specific antibodies between groups.

RESULTS

The group immunized with the allergoid showed significantly higher specific IgG and IgG1 values to dander allergens and specific IgG to the major allergen Fel d 1, while there were no significant changes in IgG2a and IgE values. These results could be due to a higher immunization dose. The vaccine formulation was based on the optimal defined dose for clinical efficacy of allergen immunotherapy.

CONCLUSIONS

This preclinical study carried out with the present assay has established that the allergoid of cat dander extract, as designed for its optimal use in allergen immunotherapy, produces a higher specific IgG than the native extract, in addition to showing significantly higher specific IgG1 levels, evidencing a greater effectiveness in immunization.

Next-Generation Pertussis Vaccines Based on the Induction of Protective T Cells in the Respiratory Tract

Immunization with current acellular pertussis (aP) vaccines protects against severe pertussis, but immunity wanes rapidly after vaccination and these vaccines do not prevent nasal colonization with Bordetella pertussis. Studies in mouse and baboon models have demonstrated that Th1 and Th17 responses are integral to protective immunity induced by previous infection with B. pertussis and immunization with whole cell pertussis (wP) vaccines. Mucosal Th17 cells, IL-17 and secretory IgA (sIgA) are particularly important in generating sustained sterilizing immunity in the nasal cavity. Current aP vaccines induce potent IgG and Th2-skewed T cell responses but are less effective at generating Th1 and Th17 responses and fail to prime respiratory tissue-resident memory T (TRM) cells, that maintain long-term immunity at mucosal sites. In contrast, a live attenuated pertussis vaccine, pertussis outer membrane vesicle (OMV) vaccines or aP vaccines formulated with novel adjuvants do induce cellular immune responses in the respiratory tract, especially when delivered by the intranasal route. An increased understanding of the mechanisms of sustained protective immunity, especially the role of respiratory TRM cells, will facilitate the development of next generation pertussis vaccines that not only protect against pertussis disease, but prevent nasal colonization and transmission of B. pertussis.

An immunoinformatics study on the spike protein of SARS-CoV-2 revealing potential epitopes as vaccine candidates

Background

The pandemic situation of SARS-CoV-2 infection has sparked global concern due to the disease COVID-19 caused by it. Since the first cluster of confirmed cases in China in December 2019, the infection has been reported across the continents and inflicted upon a substantial number of populations.

Method

This study is focused on immunoinformatics analyses of the SARS-CoV-2 spike glycoprotein (S protein) which is key for the viral attachment to human host cells. Computational analyses were carried out for the prediction of B-cell and T-cell (MHC class I and II) epitopes of S protein and the analyses were extended further for the prediction of their immunogenic properties. The interaction and binding affinity of T-cell epitopes with HLA-B7 were also investigated by molecular docking.

Result

Three distinct epitopes for vaccine design were predicted from the sequence of S protein. The potential B-cell epitope was KNHTSPDVDLG possessing the highest antigenicity score of 1.4039 among other B-cell epitopes. T-cell epitope for human MHC class I was VVVLSFELL with an antigenicity score of 1.0909 and binding ability to 29 MHC-I alleles. The predicted T-cell epitope for human MHC class II molecule was VVIGIVNNT with a corresponding 1.3063 antigenicity score, less digesting enzymes, and 7 MHC-II alleles binding ability. All these three peptides were predicted to be highly antigenic, non-allergenic, and non-toxic. Analyses of the physiochemical properties of these predicted epitopes indicate their stable nature for plausible vaccine design. Furthermore, molecular docking investigation between the MHC class-I epitopes and human HLA-B7 reflects the stable interaction with high affinity among them.

Conclusion

The present study posits three potential epitopes of S protein of SARS-CoV-2 predicted by immunoinformatic methods based on their immunogenic properties and interactions with the host counterpart that can facilitate the development of vaccine against SARS-CoV-2. This study can act as the springboard for the future development of the COVID-19 vaccine.

Alginate-coated chitosan nanoparticles act as effective adjuvant for hepatitis A vaccine in mice

The numerous recent hepatitis A outbreaks emphasize the need for vaccination; despite the effectiveness of the current ones, developments are needed to overcome its high cost plus some immune response limitations. Our study aims to evaluate the use of chitosan and alginate-coated chitosan nanoparticles as an adjuvant/carrier for the hepatitis A vaccine (HAV) against the traditional adjuvant alum. Immune responses towards (HAV-Al) with alum, (HAV-Ch) with chitosan, and (HAV-aCNP) with alginate-coated chitosan nanoparticles, were assessed in mice. HAV-aCNP significantly improved the immunogenicity by increasing the seroconversion rate (100%), the hepatitis A antibodies level, and the splenocytes proliferation. Thus, the HAV-aCNP adjuvant was superior to other classes in IFN-γ and IL-10 development. Meanwhile, the solution formula of HAV with chitosan showed comparable humoral and cellular immune responses to alum-adjuvanted suspension with a balanced Th1/Th2 immune pathway. The current study showed the potential of alginate-coated chitosan nanoparticles as an effective carrier for HAV. Consequently, this would impact the cost of HAV production positively.

Vieira R, Graça L, R. Almeida R, S. Câmara NO, Russo M. Dendritic Cells Expressing MyD88 Molecule Are Necessary and Sufficient for CpG-Mediated Inhibition of IgE Production In Vivo

Elevated levels of immunoglobulin E (IgE) are associated with allergies and other immunological disorders. Sensitization with alum adjuvant favours IgE production while CpG-ODN adjuvant, a synthetic toll-like receptor 9 (TLR9) agonist, inhibits it. The cellular mechanisms underlying in vivo TLR regulation of immunoglobulin production, specially IgE, are still controversial. Specifically, TLR-mediated IgE regulation in vivo is not yet known. In this study we showed that augmented levels of IgE induced by sensitizations to OVA with or without alum adjuvant or with OVA-pulsed dendritic cells (DCs) were inhibited by co-administration of CpG. Notably, CpG-mediated suppression of IgE production required MyD88-expression on DCs but not on B-cells. This finding contrasts with previous in vitro studies reporting regulation of IgE by a direct action of CpG on B cells via MyD88 pathway. In addition, we showed that CpG also inhibited IgE production in a MyD88-dependent manner when sensitization was performed with OVA-pulsed DCs. Finally, CpG signalling through MyD88 pathway was also necessary and sufficient to prevent anaphylactic antibody production involved in active cutaneous anaphylaxis.

Immunogenicity of Protein Pharmaceuticals

Protein therapeutics have drastically changed the landscape of treatment for many diseases by providing a regimen that is highly specific and lacks many off-target toxicities. The clinical utility of many therapeutic proteins has been undermined by the potential development of unwanted immune responses against the protein, limiting their efficacy and negatively impacting its safety profile. This review attempts to provide an overview of immunogenicity of therapeutic proteins, including immune mechanisms and factors influencing immunogenicity, impact of immunogenicity, preclinical screening methods, and strategies to mitigate immunogenicity.

Novel imiquimod nanovesicles for topical vaccination

Development of needle and pain free noninvasive immunization procedures is a top priority for public health agencies. In this work the topical adjuvant activity of the immunomodulator imiquimod (IMQ) carried by ultradeformable archaeosomes (UDA₂) (nanovesicles containing sn-2,3 ether linked phytanyl saturated archaeolipids) was surveyed and compared with that of ultradeformable liposomes lacking archaeolipids (UDL₂) and free IMQ, using the model antigen ovalbumin and a seasonal influenza vaccine in Balb/c mice. UDA₂ (250 ± 94 nm, -26 ± 4 mV Z potential) induced higher IMQ accumulation in human skin and higher production of TNF-α and IL-6 by macrophages and keratinocytes than free IMQ and UDL₂. Mixed with ovalbumin, UDA₂ was more efficient at generating cellular response, as measured by an increase in serum IgG2a and INF-γ production by splenocytes, compared with free IMQ and UDL₂. Moreover, mixed with a seasonal influenza vaccine UDA₂ produced same IgG titers and IgG2a/IgG1 isotypes ratio (≈1) than the subcutaneously administered influenza vaccine. Topical UDA₂ however, induced highest stimulation index and INF-γ levels by splenocytes. UDA₂ might be a promising adjuvant for topical immunization, since it produced cell-biased systemic response with ≈ 13-fold lower IMQ dose than the delivered as the commercial IMQ cream, Aldara.

Make It Simple: (SR-A1+TLR7) Macrophage Targeted NANOarchaeosomes

Hyperhalophilic archaebacteria exclusively produce sn2,3 diphytanylglycerol diether archaeolipids, unique structures absent in bacteria and eukaryotes. Nanovesicles made of archaeolipids known as nanoarchaeosomes (nanoARC), possess highly stable bilayers, some of them displaying specific targeting ability. Here we hypothesize that nanoARC made from Halorubrum tebenquichense archaebacteria, may constitute efficient carriers for the TLR7 agonist imiquimod (IMQ). NanoARC-IMQ takes advantage of the intense interaction between IMQ and the highly disordered, poorly fluid branched archaeolipid bilayers, rich in archaeol analog of methyl ester of phosphatidylglycerophosphate (PGP-Me), a natural ligand of scavenger receptor A1 (SR-A1). This approach lacks complex manufacture steps required for bilayers labeling, enabling future analytical characterization, batch reproducibility, and adaptation to higher scale production. SR-A1 mediated internalization of particulate material is mostly targeted to macrophages and is extensive because it is not submitted to a negative feedback. A massive and selective intracellular delivery of IMQ may concentrate its effect specifically into the endosomes, where the TLR7 is expressed, magnifying its immunogenicity, at the same time reducing its systemic bioavailability, and therefore it's in vivo adverse effects. NanoARC-IMQ (600-900 nm diameter oligolamellar vesicles of ~-43 mV Z potential) were heavily loaded with IMQ at ~44 μg IMQ/mg phospholipids [~20 folds higher than the non-SR-A1 ligand soyPC liposomes loaded with IMQ (LIPO-IMQ)]. In vitro, nanoARC-IMQ induced higher TNF-α and IL-6 secretion by J774A1 macrophages compared to same dose of IMQ and same lipid dose of LIPO-IMQ. In vivo, 3 subcutaneous doses of nanoARC-IMQ+ 10 μg total leishmania antigens (TLA) at 50 μg IMQ per Balb/C mice, induced more pronounced DTH response, accompanied by a nearly 2 orders higher antigen-specific systemic IgG titers than IMQ+TLA and LIPO-IMQ. The isotype ratio of nanoARC-IMQ+TLA remained ~0.5 indicating, the same as IMQ+TLA, a Th2 biased response distinguished by a pronounced increase in antibody titers, without negative effects on splenocytes lymphoproliferation, with a potential CD8+LT induction 10 days after the last dose. Overall, this first approach showed that highly SR-A1 mediated internalization of heavily loaded nanoARC-IMQ, magnified the effect of IMQ on TLR7 expressing macrophages, leading to a more intense in vivo immune response.

Suppressive Effect of 4-Hydroxy-2-(4-Hydroxyphenethyl) Isoindoline-1,3-Dione on Ovalbumin-Induced Allergic Asthma

4-Hydroxy-2-(4-hydroxyphenethyl)isoindoline-1,3-dione (PD1) is a synthetic phthalimide derivative of a marine compound. PD1 has peroxisome proliferator-activated receptor (PPAR) γ agonistic and anti-inflammatory effects. This study aimed to investigate the effect of PD1 on allergic asthma using rat basophilic leukemia (RBL)-2H3 mast cells and an ovalbumin (OVA)-induced asthma mouse model. In vitro, PD1 suppressed β-hexosaminidase activity in RBL-2H3 cells. In the OVA-induced allergic asthma mouse model, increased inflammatory cells and elevated Th2 and Th1 cytokine levels were observed in bronchoalveolar lavage fluid (BALF) and lung tissue. PD1 administration decreased the numbers of inflammatory cells, especially eosinophils, and reduced the mRNA and protein levels of the Th2 cytokines including interleukin (IL)-4 and IL-13, in BALF and lung tissue. The severity of inflammation and mucin secretion in the lungs of PD1-treated mice was also less. These findings indicate that PD1 could be a potential compound for anti-allergic therapy.

Evaluation of intranasal and subcutaneous route of immunization in neonatal mice using DODAB-BF as adjuvant with outer membrane vesicles of Neisseria meningitis B

BACKGROUND

The Neisseria meningitidis bacterium is a Gram-negative diplococcus that can be classified into different serogroups according to the capsular structure. Six of them (A, B, C, W, X, Y) are responsible for causing Invasive Meningococcal Disease (IMD). The strategies for the development of a vaccine for serogroup B have been directed to the use of outer membrane vesicles (OMVs). The aim of this study was to evaluate the immunogenicity of antigenic determinants from OMVs of N. meningitidis B complexed with two different adjuvants: DODAB-BF and aluminum hydroxide (alum), comparing the evaluation of intranasal and subcutaneous route of immunization.

METHODS

We used prime-boost immunization for the first time in outbred neonatal mice evaluating the cellular and humoral immune response.

RESULTS

Immunoblot, ELISA DOT-ELISA and ELISpot were used universal methods of antibody detection, in order to detect the humoral and cellular immune response in male and female mice. Immunoblot analyzes the specificity of antibodies with the homologous N. meningitidis strain. ELISA served to quantify and compare the titers of antibodies in the serum of mice immunized with DODAB-BF + OMVs and alum + OMVs for IgG, IgG1, and IgG2a. Intranasal immunization produced a mixed response in the T helper cells Th1 and Th2, while subcutaneous immunization exhibited a Th1 profile. The DOT-ELISA identified cross-reactivity with DODAB-BF to different serogroups of N. meningitidis (B, C, W, and Y) that was not observed with alum. ELISpot analyzed IFN-γ- and IL-4 and the results showed the response directly to Th1 and Th2 profile.

CONCLUSION

Our findings indicate that DODAB-BF can be an alternative adjuvant for mucosal cell activation with OMVs of N. meningitidis B and that DODAB-BF was similar to aluminum hydroxide as an adjuvant for subcutaneous immunization.

Synthesis, Liposomal Formulation, and Immunological Evaluation of a Minimalistic Carbohydrate-α-GalCer Vaccine Candidate

Fully synthetic glycan-based vaccines hold great potential as preventive and therapeutic vaccines against infectious diseases as well as cancer. Here, we present a two-component platform based on the facile conjugation of carbohydrate antigens to α-galactosylceramide (α-GalCer) to yield fully synthetic vaccine candidates. Formulation of the cancer-associated Tn antigen glycolipid model vaccine candidate into liposomes of different sizes and subsequent immunization of mice generated specific, high-affinity antibodies against the carbohydrate antigen with characteristics of T cell-dependent immunity. Liposome formulation elicited more reproducible glycan immunity than a conventional glycoconjugate vaccine bearing the same glycan antigen did. Further evaluation of the immune response revealed that the size of the liposomes influenced the glycan antibody responses toward either a cellular (Th1) or a humoral (Th2) immune phenotype. The glycolipid vaccine platform affords strong and robust antiglycan antibody responses in vivo without the need for an external adjuvant.

Protocol for Pertussis Immunisation and Food Allergy (PIFA): a case-control study of the association between pertussis vaccination in infancy and the risk of IgE-mediated food allergy among Australian children

INTRODUCTION

Atopic diseases, including food allergy, have become a predominant cause of chronic illness among children in developed countries. In Australia, a rise in hospitalisations among infants coded as anaphylaxis to foods coincided with the replacement of whole-cell pertussis (wP) vaccine with subunit acellular pertussis (aP) vaccine on the national immunisation schedule in the late 1990s. Atopy is characterised by a tendency to mount T helper type 2 (Th2) responses to otherwise innocuous environmental antigens. Compared with infants who receive aP as their first pertussis vaccine, those who receive wP appear less likely to mount Th2 immune responses to either vaccine or extraneous antigens. We therefore speculate that removal of wP from the vaccine schedule contributed to the observed rise in IgE-mediated food allergy among Australian infants.

METHODS AND ANALYSIS

This is a retrospective individually matched case-control study among a cohort of Australian children born from 1997 to 1999, the period of transition from wP to aP vaccines; we include in the cohort children listed on Australia's comprehensive population-based immunisation register as having received a first dose of either pertussis vaccine by 16 weeks old. 500 cohort children diagnosed as having IgE-mediated food allergy at specialist allergy clinics will be included as cases. Controls matched to each case by date and jurisdiction of birth and regional socioeconomic index will be sampled from the immunisation register. Conditional logistic regression will be used to estimate OR (±95% CI) of receipt of wP (vs aP) as the first vaccine dose among cases compared with controls.

ETHICS AND DISSEMINATION

The study is approved by all relevant human research ethics committees: Western Australia Child and Adolescent Health Services (2015052EP), Women's and Children's Hospital (HREC/15/WCHN/162), Royal Children's Hospital (35230A) and Sydney Children's Hospital Network (HREC/15/SCHN/405). Outcomes will be disseminated through publication and scientific presentation.

TRIAL REGISTRATION NUMBER

NCT02490007.

Magnetic Nanovectors for the Development of DNA Blood-Stage Malaria Vaccines

DNA vaccines offer cost, flexibility, and stability advantages, but administered alone have limited immunogenicity. Previously, we identified optimal configurations of magnetic vectors comprising superparamagnetic iron oxide nanoparticles (SPIONs), polyethylenimine (PEI), and hyaluronic acid (HA) to deliver malaria DNA encoding Plasmodium yoelii (Py) merozoite surface protein MSP1₁₉ (SPIONs/PEI/DNA + HA gene complex) to dendritic cells and transfect them with high efficiency in vitro. Herein, we evaluate their immunogenicity in vivo by administering these potential vaccine complexes into BALB/c mice. The complexes induced antibodies against PyMSP1₁₉, with higher responses induced intraperitoneally than intramuscularly, and antibody levels further enhanced by applying an external magnetic field. The predominant IgG subclasses induced were IgG2a followed by IgG1 and IgG2b. The complexes further elicited high levels of interferon gamma (IFN-γ), and moderate levels of interleukin (IL)-4 and IL-17 antigen-specific splenocytes, indicating induction of T helper 1 (Th1), Th2, and Th17 cell mediated immunity. The ability of such DNA/nanoparticle complexes to induce cytophilic antibodies together with broad spectrum cellular immunity may benefit malaria vaccines.

Effectiveness of F18+ Fimbrial Antigens Released by a Novel Autolyzed Salmonella Expression System as a Vaccine Candidate against Lethal F18+ STEC Infection

Porcine edema disease (ED) caused by Shiga toxin 2e producing Escherichia coli expressing F18ab⁺ fimbriae (F18ab⁺STEC) frequently occurs in post-weaned piglets, resulting in a significant economic loss in swine industries worldwide. In the present study, we proposed an efficient prevention scheme against ED in which the attenuated Salmonella Typhimurium inactivated by the E-mediated cell lysis to deliver target antigens, FedF and FedA, which function in fimbrial-mediated adhesion and as a major subunit of F18ab+fimbriae, respectively. The co-expression of FedA and FedF protein with outer membrane protein A signal peptide was confirmed in the resultant strains JOL1460 and JOL1464 by immunoblot analysis. Immunization with the candidate strains in mice led to the significant generation of immunoglobulin (Ig) G, specific to both antigens and secretory IgA specific to FedF (P < 0.05). The titers of IgG isotypes, IgG1 and IgG2a, used as markers for T-helpers (Th)-2 and Th-1lymphocytes, respectively, also significantly increased in the immunized group (P < 0.05). The increase in CD3⁺CD4⁺ T lymphocyte subpopulation and in vitro proliferative activity was observed in in vivo stimulated splenocytes, which indicated the immunostimulatory effect of the candidate strains. Moreover, the immunized mice were completely protected from a lethal challenge against wild-type F18⁺STEC whereas 28% of mice died in the non-immunized group. This study demonstrated that the inactivated Salmonella system could efficiently release FedF and FedA and induce robust immune responses specific to the target antigens, which is sufficient to protect the mice from the lethal challenge.

A Rapid-Response Humoral Vaccine Platform Exploiting Pre-Existing Non-Cognate Populations of Anti-Vaccine or Anti-Viral CD4+ T Helper Cells to Confirm B Cell Activation

The need for CD4+ T cell responses to arise de novo following vaccination can limit the speed of B cell responses. Populations of pre-existing vaccine-induced or anti-viral CD4+ T cells recognising distinct antigens could be exploited to overcome this limitation. We hypothesise that liposomal vaccine particles encapsulating epitopes that are recognised, after processing and B cell MHCII presentation, by pre-existing CD4+ T cells will exploit this pre-existing T cell help and result in improved antibody responses to distinct target antigens displayed on the particle surface. Liposomal vaccine particles were engineered to display the malaria circumsporozoite (CSP) antigen on their surface, with helper CD4+ epitopes from distinct vaccine or viral antigens contained within the particle core, ensuring the B cell response is raised but focused against CSP. In vivo vaccination studies were then conducted in C57Bl/6 mice as models of either vaccine-induced pre-existing CD4+ T cell immunity (using ovalbumin-OVA) or virus-induced pre-existing CD4+ T cell immunity (murine cytomegalovirus-MCMV). Following the establishment of pre-existing by vaccination (OVA in the adjuvant TiterMax® Gold) or infection with MCMV, mice were administered CSP-coated liposomal vaccines containing the relevant OVA or MCMV core CD4+ T cell epitopes. In mice with pre-existing anti-OVA CD4+ T cell immunity, these vaccine particles elicited rapid, high-titre, isotype-switched CSP-specific antibody responses-consistent with the involvement of anti-OVA T helper cells in confirming activation of anti-CSP B cells. Responses were further improved by entrapping TLR9 agonists, combining humoral vaccination signals 'one', 'two' and 'three' within one particle. Herpes viruses can establish chronic infection and elicit significant, persistent cellular immune responses. We then demonstrate that this principle can be extended to re-purpose pre-existing anti-MCMV immunity to enhance anti-CSP vaccine responses-the first description of a strategy to specifically exploit anti-cytomegalovirus immunity to augment vaccination against a target antigen.

The epithelial barrier and immunoglobulin A system in allergy

Airway and intestinal epithelial layers represent first-line physical barriers, playing a key role in mucosal immunity. Barrier dysfunction, characterized by alterations such as disruption of cell-cell apical junctions and aberrant epithelial responses, probably constitutes early and key events for chronic immune responses to environmental antigens in the skin and in the gut. For instance, barrier dysfunction drives Th2 responses in atopic disorders or eosinophilic esophagitis. Such epithelial impairment is also a salient feature of allergic asthma and growing evidence indicates that barrier alterations probably play a driving role in this disease. IgA has been identified as the most abundant immunoglobulin in mucosa, where it acts as an active barrier through immune exclusion of inhaled or ingested antigens or pathogens. Historically, it has been thought to represent the serum factor underlying reaginic activity before IgE was discovered. Despite several studies about regulation and major functions of IgA at mucosal surfaces, its role in allergy remains largely unclear. This review aims at summarizing findings about epithelial functions and IgA biology that are relevant to allergy, and to integrate the emerging concepts and the recent developments in mucosal immunology, and how these could translate to clinical observations in allergy.

Pharmacokinetics and Differential Regulation of Cytochrome P450 Enzymes in Type 1 Allergic Mice

Type 1 allergic diseases are characterized by elevated production of specific immunoglobulin E (IgE) for each antigen and have become a significant health problem worldwide. This study investigated the effect of IgE-mediated allergy on drug pharmacokinetics. To further understand differential suppression of hepatic cytochrome P450 (P450) activity, we examined the inhibitory effect of nitric oxide (NO), a marker of allergic conditions. Seven days after primary sensitization (PS7) or secondary sensitization (SS7), hepatic CYP1A2, CYP2C, CYP2E1, and CYP3A activities were decreased to 45%-75% of the corresponding control; however, CYP2D activity was not downregulated. PS7 and SS7 did not change the expression levels of five P450 proteins. Disappearance of CYP1A2 and CYP2D substrates from the plasma was not significantly different between allergic mice and control mice. In contrast, the area under the curve of a CYP1A2-mediated metabolite in PS7 and SS7 mice was reduced by 50% of control values. Total clearances of a CYP2E1 substrate in PS7 and SS7 mice were significantly decreased to 70% and 50% respectively, of the control without altering plasma protein binding. Hepatic amounts of CYP1A2 and CYP2E1 substrates were enhanced by allergic induction, being responsible for each downregulated activity. NO scavenger treatment completely improved the downregulated P450 activities. Therefore, our data suggest that the onset of IgE-mediated allergy alters the pharmacokinetics of major P450-metabolic capacity-limited drugs except for CYP2D drugs. NO is highly expected to participate in regulatory mechanisms of the four P450 isoforms.

Synthetic Lipoteichoic Acid Glycans Are Potential Vaccine Candidates to Protect from Clostridium difficile Infections

Infections with Clostridium difficile increasingly cause morbidity and mortality worldwide. Bacterial surface glycans including lipoteichoic acid (LTA) were identified as auspicious vaccine antigens to prevent colonization. Here, we report on the potential of synthetic LTA glycans as vaccine candidates. We identified LTA-specific antibodies in the blood of C. difficile patients. Therefore, we evaluated the immunogenicity of a semi-synthetic LTA-CRM₁₉₇ glycoconjugate. The conjugate elicited LTA-specific antibodies in mice that recognized natural LTA epitopes on the surface of C. difficile bacteria and inhibited intestinal colonization of C. difficile in mice in vivo. Our findings underscore the promise of synthetic LTA glycans as C. difficile vaccine candidates.

Cytokines Involved in the Pathophysiology of IgE Response

Recent data in both mouse and human systems have clearly indicated that IL-4 plays an essential role in the induction of IgE response, whereas IFN-γ exerts an opposite effect on this phenomenon. However, IL-4 alone is unable to induce IgE synthesis. A prior membrane contact signal delivered by activated T cells is required by B cells to synthesize IgE in response to IL-4. A cognate interaction between B and T cells producing IL-4 (but not IFN-γ) is optimal for induction of IgE synthesis. However, when such IL-4 producing T cells are activated, they may provide B cells with a membrane signal, through a non-cognate interaction, which also results in induction of IgE synthesis. Other cytokines, such as IL-2 and IL-6, play an auxiliary role in IL-4 dependent IgE production.

Analyses at the clonal level of the profile of cytokine production by helper T cells have shown that imbalances between IL-4 and IFN-γ producing T cells can be detected in patients with hyperproduction of IgE. In children with hyper-IgE syndrome a strong reduction of circulating T cells able to produce IFN-γ (and TNF-α) was found, whereas both, reduction of IFN-γ-producing and increase of IL-4 producing T cells were found in patients with parasitic infestation. In allergic inflammatory infiltrates, such as those found in vernal conjuctivitis, helper T cells able to produce IL-4 and to induce IgE synthesis accounted for the large majority of infiltrating T cells. It is reasonable to suggest that systemic or microenvironmental alterations of the balance between IL-4- and IFN-γ-producing T cells may be involved, at least in part, in the pathophysiology of the increased igE response occurring in a number of human diseases.

Cytokines and Thyroid Autoimmunity

Cytokines may play important roles in the development and perpetuation of autoimmunity. In this paper are briefly reviewed selected data on the relationship between cytokines and thyroid autoimmune diseases (AITD), which represent a typical example of organ-specific autoimmune endocrinopathy. The availability of high efficiency T-cell cloning techniques recently allowed the phenotipic and functional characterization of T lymphocytes derived from thyroid infiltrates of patients with Graves' disease and Hashimoto's thyroiditis. A high prevalence of T cell clones with cytolytic potential and displaying increased γ-interferon production was observed in both diseases; in contrast, high tumor necrosis factor-α secretion was a peculiar characteristic of T-cell clones derived only from Hashimoto's infiltrates. The production of IL-4 by CD4 + T cell clones from AITD infiltrates was remarkably low, suggesting a quite homogeneous populations of Thl-type «inflammatory» T cells. This pattern of cytokine production by thyroid infiltrates may be important not only in triggering and/or maintaining thyroid autoimmune reaction, but could also modulate the expression of AITD by exerting direct functional effects on thyroid epithelial cells, as suggested by recent in vitro studies.

Leishmania infantum-specific production of IFN-γ and IL-10 in stimulated blood from dogs with clinical leishmaniosis

BACKGROUND

There is limited information available on cytokine profiles in dogs with different degrees of disease severity due to natural infection of Leishmania infantum. The aim of this study was to investigate L. infantum-specific IFN-γ and IL-10 production in blood from dogs with leishmaniosis at diagnosis and correlate these findings with disease severity, humoral immune response and blood parasitemia.

METHODS

Sixty dogs were diagnosed based on physical examination, routine laboratory tests, L. infantum-specific antibody levels measured by quantitative ELISA and blood parasitemia by real-time PCR. Heparin whole blood was stimulated with L. infantum soluble antigen (LSA) and concanavalin A (ConA) and incubated for 5 days. IFN-γ and IL-10 concentrations were measured in supernatants with sandwich ELISAs.

RESULTS

The majority of dogs (n = 36) were classified as LeishVet stage II (moderate disease). The rest of the dogs were classified as stage I (n = 10), III (n = 10) and IV (n = 4). Dogs classified with stage I and IIa presented significantly higher (P = 0.02) LSA IFN-γ concentrations, lower (P <0.0001) antibody levels and a tendency for lower blood parasitemia (P = 0.1) than dogs classified with stages IIb, III or IV while no differences in ConA IFN-γ or IL-10 concentrations were observed among groups. Thirty-five dogs produced significantly higher LSA IFN-γ (mean ± SD: 2320 ± 3960 pg/ml) and ConA IFN-γ (mean ± SD: 7887 ± 7273 pg/ml) when compared with 25 dogs that did not produce detectable LSA IFN-γ but produced ConA IFN-γ (mean ± SD: 4917 ± 5233 pg/ml). IFN-γ producer dogs presented lower (mean ± SD: 5750 ± 14,082 ELISA units (EU), P = 0.001) antibody levels and blood parasitemia (mean ± SD:   5 ± 10 parasites/ml, P = 0.001) when compared with IFN-γ non-producers (mean ± SD: 19,638 ± 28,596 EU and 1100 ± 5112 parasites/ml), respectively. LSA IL-10 was not detectable in 34 dogs while 49 dogs secreted ConA IL-10 (mean ± SD of 90 ± 103 pg/ml). LSA IFN-γ concentration was negatively correlated with blood parasitemia and antibody levels and positively correlated with ConA IFN-γ and LSA IL-10 concentrations.

CONCLUSIONS

The results of this study demonstrate that sick dogs lacking L. infantum specific IFN-γ production in stimulated whole blood produce a strong humoral response, have a high blood parasitemia and severe clinical disease. IL-10 does not appear to be a marker of disease severity.

TAK1 deficiency in dendritic cells inhibits adaptive immunity in SRBC-immunized C57BL/6 mice

Dendritic cells (DCs) are important in the initiation of primary T‐cell responses, while transforming growth factor‐β (TGF‐β)‐activated kinase 1 (TAK1) is a critical regulator of DC survival and homeostasis. This study evaluated the T‐cell dependent antibody response (TDAR) to sheep red blood cells (SRBC) on a DC‐specific TAK1‐deficient mice model. The results showed that TAK1 deficiency in DCs significantly suppressed the humoral and cellular immune response in mice. DC‐specific TAK1 deletion impaired splenic T‐cell population and conventional DCs, abolished the cytokine production of splenic T cells and down‐regulated some functional gene expression in the spleen. Collectively, this study suggests that TAK1 plays an essential role in the development of the humoral immune response.

Trichloroethylene-induced hypersensitivity dermatitis was associated with hepatic metabolic enzyme genes and immune-related genes

Trichloroethylene (TCE) is one of the common organic solvents that has been widely used in cleaning or degreasing of metal and electronic products. However, hundreds of cases of hypersensitivity dermatitis have occurred after the workers were occupationally exposed to TCE in China over the past decade. The purpose of this study was to investigate mRNA expression of hepatic metabolic enzyme genes, immune-related genes, apoptosis genes and oncogenes in patients with hypersensitivity dermatitis induced by trichloroethylene. 12 typical patients with TCE-induced hypersensitivity dermatitis were investigated as the study cases, peripheral blood samples were taken from patients and control, and real-time fluorescence PCR assay was applied for detection of mRNA expression of hepatic metabolic enzyme genes, immune-related genes, apoptosis genes and oncogenes. It was found that the relative levels of mRNA expression of CYP1A2, CYP2E1, CYP3A4 and CYP2C9 increased by 723%, 318%, 385% and 216%, respectively, when compared with control (p < 0.01 or p < 0.05); Foxp3, GATA3 and CTLA4 mRNA expression increased by 104%, 106% and 253%, respectively, in TCE patients when compared with control (p < 0.01); T-bet expression decreased by 44% when compared with control (p < 0.01); these findings indicate that some immune-related genes and hepatic metabolic enzyme genes might play an important role in the process of trichloroethylene-induced hypersensitivity dermatitis.

Immunological adjuvant effect of the peptide fraction from the larvae of Musca domestica

BACKGROUND

The larvae of Musca domestica (Diptera: Muscidae) have been used traditionally for malnutritional stagnation, decubital necrosis, osteomyelitis, ecthyma and lip scald and also to treat coma and gastric cancer in the traditional Chinese medicine. Its immunomodulatory effects in naïve mice in relation to the traditional uses were also reported. However, the immunological adjuvant potentials of this insect have not yet been studied.

METHODS

The peptide fraction from the larvae of Musca domestica L. (MDPF) was evaluated for its adjuvant potentials on the immune responses to ovalbumin (OVA) and avian influenza vaccine (rL-H5) by determining antigen-specific antibody titers, splenocyte proliferation, activity of natural killer (NK) cell, the secretion of cytokines from splenocytes in the immunized mice.

RESULTS

MDPF significantly enhanced not only the concanavalin A (Con A)-, lipopolysaccharide (LPS)- and antigen-stimulated splenocyte proliferation, but serum antigen-specific IgG, IgG1, IgG2a, and IgG2b antibody titers in the mice immunized with OVA and rL-H5. MDPF also remarkably promoted the killing activities of NK cells in splenocytes from the mice immunized with rL-H5. Furthermore, MDPF significantly promoted the production of Th1 (IL-2 and IFN-γ) and Th2 (IL-10) cytokines from splenocytes in the immunized mice.

CONCLUSIONS

The results indicated that MDPF had a potential to increase both cellular and humoral immune responses and elicit a balanced Th1/Th2 response, and that MDPF may be a safe and efficacious vaccine adjuvant candidate.

Migration of splenic lymphocytes promotes liver fibrosis through modification of T helper cytokine balance in mice

BACKGROUND

Sustained liver injury causes liver fibrosis and eventually cirrhosis. Understanding the pathophysiological mechanisms of liver fibrosis and interventions in the fibrotic process is crucial for improving the prognosis of patients with chronic liver diseases. Although studies have shown that splenectomy suppresses liver fibrosis, the mechanism by which this occurs is poorly understood. The present study focuses on the immunological functions of the spleen to investigate its role in liver fibrosis.

METHODS

BALB/c and severe combined immunodeficiency (SCID) mice underwent splenectomies or sham operations prior to induction of liver fibrosis with carbon tetrachloride or thioacetamide.

RESULTS

Sirius red staining and hydroxyproline assays showed that splenectomy suppressed liver fibrogenesis in BALB/c mice. Reverse transcription PCR analysis of T helper type 1 (Th1) and T helper type 2 (Th2) cytokines demonstrated that splenectomy shifted the Th1/Th2 balance in the liver towards Th1 dominance. In SCID mice, the inhibitory effect on liver fibrosis was abrogated. The number of CD4(+) T helper lymphocytes in the spleen decreased after liver injury. Green fluorescent protein positive (GFP(+)) splenocytes were transplanted into the spleens of syngeneic wild-type mice to trace their destination after fibrosis induction. GFP(+)CD4(+) lymphocytes appeared in the liver after induction of fibrosis, and flow cytometry revealed the vast majority of them were Th2 lymphocytes. Transfer of splenocytes via the portal vein into syngeneic splenectomized mice cancelled the suppressive effect of splenectomy on liver fibrosis.

CONCLUSIONS

The present study demonstrated that Th2-dominant splenic lymphocytes migrate into the liver and promote liver fibrosis by shifting the cytokine balance towards Th2 dominance. Splenectomy suppresses the progression of fibrosis at least partly by restoring the Th1/Th2 balance.

Macrophage subsets and osteoimmunology: tuning of the immunological recognition and effector systems that maintain alveolar bone

Chronic and aggressive periodontal diseases are characterized by the failure to resolve local inflammation against periodontopathogenic bacteria in the subgingival biofilm. Alveolar bone resorption is associated with altered innate and adaptive immune responses to periodontal pathogens. Macrophage-derived cytokines, chemokines and growth factors, present in both destructive and reparative phases of periodontitis, are elevated in numerous animal and human studies. Macrophage polarization to either a predominantly pro-inflammatory or anti-inflammatory phenotype may be a critical target for monitoring disease activity, modulating immune responses to subgingival biofilms in patients at risk and reducing alveolar bone loss.

The effect of 5-amino-3-methyl-4-isoxazolecarboxylic acid hydrazide on lymphocyte subsets and humoral immune response in SRBC-immunized mice

5-Amino-3-methyl-4-isoxazolecarboxylic acid hydrazide is a non-cytotoxic synthetic isoxazole derivative with considerable immunomodulatory properties demonstrated in in vitro experiments. The aim of this study was to investigate the influence of this compound, depending on the dosage and schedule of treatment, on lymphocyte subsets in non-immunized mice and humoral immune response in SRBC (sheep red blood cells)-immunized mice. An analysis of lymphocyte subsets was carried out by flow cytometry, using specific monoclonal antibodies stained with fluorescein isothiocyanate (FITC) or phycoerythrin (PE). In the SRBC-immunized mice, the influence of the compound on the humoral response was determined, depending on the time of administration relative to the antigen. The number of plaque forming cells (PFC) was determined by a local hemolysis technique in an agar gel. Total and 2-mercaptoethanol resistant serum agglutination titers were defined by active hemagglutination test carried out on microplates. The investigated hydrazide was able to modulate the percentage and absolute number of T lymphocyte subsets in the thymus, and T and B lymphocytes in the peripheral lymphatic organs. It also enhanced humoral immune response in SRBC-immunized mice by increasing the number of cells producing hemolytic anti-SRBC antibodies (PFC) and by augmenting the level of total and 2-mercaptoethanol resistant hemagglutinin. The present study showed modulatory effects of 5-amino-3-methyl-4-isoxazolecarboxylic acid hydrazide on lymphocyte subsets and humoral immune response in mice. This compound could be potentially useful for the treatment of autoimmune diseases, infections or as an adjuvant for boosting the efficacy of vaccines.

Experimental infection of brown-marbled grouper, Epinephelus fuscoguttatus (Forskal), with Vibrio parahaemolyticus identifies parvalbumin beta-2 subunit I, alpha-2-macroglobulin, nattectin and immunoglobulin light chain, differentially expressed in resistant grouper

The mechanisms through which brown-marbled grouper accomplishes resistance to infection, particularly against Vibrios, are not yet fully understood. In this study, brown-marbled grouper fingerlings were experimentally infected with Vibrio parahaemolyticus, to identify disease resistance grouper, and the serum proteome profiles were compared between resistant and susceptible candidates, via two-dimensional gel electrophoresis (2-DE). The results showed that putative parvalbumin beta-2 subunit I, alpha-2-macroglobulin, nattectin and immunoglobulin light chain proteins were among proteins that significantly overexpressed in the resistant fish as compared to the susceptible group of fish, whereas apolipoprotein E and immunoglobulin light chain proteins were observed to be differentially overexpressed in the susceptible fish. Further analysis by peptide sequencing revealed that the immunoglobulin light chain proteins identified in the resistant and susceptible groups differed in amino acid composition. Taken together, the results demonstrated for the first time that putative parvalbumin beta-2 subunit I, alpha-2-macroglobulin, nattectin and immunoglobulin light chain are among important proteins participating to effect disease resistance mechanism in fish and were overexpressed to function collectively to resist V. parahaemolyticus infection. Most of these molecules are mediators of immune response.

Ginseng diminishes lung disease in mice immunized with formalin-inactivated respiratory syncytial virus after challenge by modulating host immune responses

Formalin-inactivated respiratory syncytial virus (FI-RSV) immunization is known to cause severe pulmonary inflammatory disease after subsequent RSV infection. Ginseng has been used in humans for thousands of years due to its potential health benefits. We investigated whether ginseng would have immune modulating effects on RSV infection in mice previously immunized with FI-RSV. Oral administration of mice with ginseng increased IgG2a isotype antibody responses to FI-RSV immunization, indicating T-helper type 1 (Th1) immune responses. Ginseng-treated mice that were nonimmunized or previously immunized with FI-RSV showed improved protection against RSV challenge compared with control mice without ginseng treatment. Ginseng-mediated improved clinical outcomes after live RSV infection were evidenced by diminished weight losses, decreased interleukin-4 cytokine production but increased interferon-γ production, modulation of CD3 T-cell populations toward a Th1 response, and reduced inflammatory response. Ginseng-mediated protective host immune modulation against RSV pulmonary inflammation was observed in different strains of wild-type and mutant mice. These results indicate that ginseng can modulate host immune responses to FI-RSV immunization and RSV infection, resulting in protective effects against pulmonary inflammatory disease.

DBC1 is a suppressor of B cell activation by negatively regulating alternative NF-κB transcriptional activity

CD40 and BAFFR signaling play important roles in B cell proliferation and Ig production. In this study, we found that B cells from mice with deletion of Dbc1 gene (Dbc1(-/-)) show elevated proliferation, and IgG1 and IgA production upon in vitro CD40 and BAFF, but not BCR and LPS stimulation, indicating that DBC1 inhibits CD40/BAFF-mediated B cell activation in a cell-intrinsic manner. Microarray analysis and chromatin immunoprecipitation experiments reveal that DBC1 inhibits B cell function by selectively suppressing the transcriptional activity of alternative NF-κB members RelB and p52 upon CD40 stimulation. As a result, when immunized with nitrophenylated-keyhole limpet hemocyanin, Dbc1(-/-) mice produce significantly increased levels of germinal center B cells, plasma cells, and Ag-specific Ig. Finally, loss of DBC1 in mice leads to higher susceptibility to experimental autoimmune myasthenia gravis. Our study identifies DBC1 as a novel regulator of B cell activation by suppressing the alternative NF-κB pathway.

The immune response of two microbial antigens delivered intradermally, sublingually, or the combination thereof

A key consideration to produce a successful vaccine is the choice of appropriate vaccination route. Though most vaccines are administered parenterally, this route is not effective in producing a robust mucosal or cell-mediated response. Intradermal and sublingual vaccinations have been explored recently as potential needle-free immunization strategies. We explored intradermal and sublingual routes as well as the combination of the two routes in eliciting both systemic and mucosal immune responses. Mice were immunized intradermally or sublingually with dmLT, a mutant of Escherichia coli heat-labile toxin. A systemic IgG response is dominant in intradermal immunization while a mucosal IgA response is dominant in sublingual immunization. When routes were combined, a synergistic response was seen with high titers of anti-dmLT IgG and IgA. IpaB/IpaD antigens of Shigella flexneri type III secretion system, were admixed with dmLT as adjuvant and administered by each route alone or in combination. Again, the intradermal route elicited a systemic response while the sublingual route elicited a mucosal response. When combined, the routes produced a robust synergistic response to both antigens that exhibited a balanced Th1/Th2 response. These results provide a new potential needle-free immunization strategy that will benefit low income countries and increase compliance in industrial countries.

Mucosal immunization of calves with recombinant bovine adenovirus-3 coexpressing truncated form of bovine herpesvirus-1 gD and bovine IL-6

Previous studies have suggested an important role of the cytokine adjuvant IL-6 in the induction of mucosal immune responses in animals, including mice. Here, we report the in vivo ability of bovine adenovirus (BAdV)-3 expressing bovine (Bo) IL-6, to influence the systemic and mucosal immune responses against bovine herpesvirus (BHV)-1 gDt in calves. To co-express both antigen and cytokine, we first constructed a recombinant BAdV-3 expressing chimeric gDt.BoIL-6 protein (BAV326). Secondly, we constructed another recombinant BAdV-3 simultaneously expressing gDt and BoIL-6 using IRES containing a bicistronic cassette gDt-IRES.IL-6, (BAV327). Recombinant proteins expressed by BAV326 and BAV327 retained antigenicity (gDt) and biological activity (BoIL-6). Intranasal immunization of calves with recombinant BAV326, BAV327 or BAV308 (gDt alone) resulted in demonstrable levels of gDt-specific IgG responses in sera and IgA response in nasal secretions, in all animals. In addition, all calves developed complement-independent neutralizing antibody responses against BHV-1. However, no significant difference could be observed in the induction of systemic or mucosal immune response in animals immunized with recombinant BAV326 or BAV327 co-expressing BoIL-6. Moreover, there was no difference in the protection against BHV-1 challenge particularly in the amount of virus excretion in the nasal cavity in calves immunized with BAV326, BAV327 or BAV308. These data suggest that the BoIL-6 had no modulating effect on the induction of gDt specific mucosal and systemic immune responses in calves.