ISCOMs/MPLA-Adjuvanted SDAD Protein Nanoparticles Induce Improved Mucosal Immune Responses and Cross-Protection in Mice.

The epidemics caused by the influenza virus are a serious threat to public health and the economy. Adding appropriate adjuvants to improve immunogenicity and finding effective mucosal vaccines to combat respiratory infection at the portal of virus entry are important strategies to boost protection. In this study, a novel type of core/shell protein nanoparticle consisting of influenza nucleoprotein (NP) as the core and NA1-M2e or NA2-M2e fusion proteins as the coating antigens by SDAD hetero-bifunctional crosslinking is exploited. Immune-stimulating complexes (ISCOMs)/monophosphoryl lipid A (MPLA) adjuvants further boost the NP/NA-M2e SDAD protein nanoparticle-induced immune responses when administered intramuscularly. The ISCOMs/MPLA-adjuvanted protein nanoparticles are delivered through the intranasal route to validate the application as mucosal vaccines. ISCOMs/MPLA-adjuvanted nanoparticles induce significantly strengthened antigen-specific antibody responses, cytokine-secreting splenocytes in the systemic compartment, and higher levels of antigen-specific IgA and IgG in the local mucosa. Meanwhile, significantly expanded lung resident memory (RM) T and B cells (TRM /BRM ) and alveolar macrophages population are observed in ISCOMs/MPLA-adjuvanted nanoparticle-immunized mice with a 100% survival rate after homogeneous and heterogeneous H3N2 viral challenges. Taken together, ISCOMs/MPLA-adjuvanted protein nanoparticles could improve strong systemic and mucosal immune responses conferring protection in different immunization routes.

A COVID-19 vaccine candidate based on SARS-CoV-2 spike protein and immune-stimulating complexes.

Spike protein from SARS-CoV-2, the etiologic agent of the COVID-19 pandemic disease, constitutes a structural protein that proved to be the main responsible for neutralizing antibody production. Thus, its sequence is highly considered for the design of candidate vaccines. Animal cell culture represents the best option for the production of subunit vaccines based on recombinant proteins since they introduce post-translational modifications that are important to mimic the natural antigenic epitopes. Particularly, the human cell line HEK293T has been explored and used for the production of biotherapeutics since the products derived from them present human-like post-translational modifications that are important for the protein's activity and immunogenicity. The aim of this study was to produce and characterize a potential vaccine for COVID-19 based on the spike ectodomain (S-ED) of SARS-CoV-2 and two different adjuvants: aluminum hydroxide (AH) and immune-stimulating complexes (ISCOMs). The S-ED was produced in sHEK293T cells using a 1-L stirred tank bioreactor operated in perfusion mode and purified. S-ED characterization revealed the expected size and morphology. High N-glycan content was confirmed. S-ED-specific binding with the hACE2 (human angiotensin-converting enzyme 2) receptor was verified. The immunogenicity of S-ED was evaluated using AH and ISCOMs. Both formulations demonstrated the presence of anti-RBD antibodies in the plasma of immunized mice, being significantly higher for the latter adjuvant. Also, higher levels of IFN-γ and IL-4 were detected after the ex vivo immune stimulation of spleen-derived MNCs from ISCOMs immunized mice. Further analysis confirmed that S-ED/ISCOMs elicit neutralizing antibodies against SARS-CoV-2. KEY POINTS: Trimeric SARS-CoV-2 S-ED was produced in stable recombinant sHEK cells in serum-free medium. A novel S-ED vaccine formulation induced potent humoral and cellular immunity. S-ED formulated with ISCOMs adjuvant elicited a highly neutralizing antibody titer.

Immunogenicity of a spike protein subunit-based COVID-19 vaccine with broad protection against various SARS-CoV-2 variants in animal studies.

SARS-CoV-2 pandemic has profound impacts on human life and global economy since the outbreak in 2019. With the new variants continue to emerge with greater immune escaping capability, the protectivity of the available vaccines is compromised. Therefore, development a vaccine that is capable of inducing immunity against variants including omicron strains is in urgent need. In this study, we developed a protein-based vaccine BCVax that is consisted of antigen delta strain spike protein and QS21-based adjuvant AB801 in nanoparticle immune stimulation complex format (AB801-ISCOM). Results from animal studies showed that high level of anti-S protein IgG was induced after two doses of BCVax and the IgG was capable of neutralizing multiple variants of pseudovirus including omicron BA.1 or BA.2 strains. In addition, strong Th1 response was stimulated after BCVax immunization. Furthermore, BCvax with AB801-ISCOM as the adjuvant showed significant stronger immunity compared with the vaccine using aluminum hydroxide plus CpG 1018 as the adjuvant. BCVax was also evaluated as a booster after two prior vaccinations, the IgG titers and pseudovirus neutralization activities against BA.2 or BA.4/BA.5 were further enhanced suggesting BCVax is a promising candidate as booster. Taken together, the pre-clinical data warrant BCVax for further development in clinic.

Immunogenicity of a recombinant hemagglutinin neuraminidase-Porcine rubulavirus produced by Escherichia coli of Porcine rubulavirus gives protective immunity of litter after challenge.

Porcine rubulavirus (PRV) is a contagious virus that affects the Mexican swine industry. This work aimed to evaluate the immunogenicity of an recombinant hemagglutinin neuraminidase-Porcine rubulavirus (rHN-PorPV) candidate vaccine on pregnant sows, and the protective efficacy afforded to their 7-day-old suckling piglets against PRV lethal challenge. Three sows were immunized with rHN-PorPV formulated with immune-stimulating complex (ISCOMs) and two sows with rHN-PorPV protein alone as well as a mock-immunized pregnant sow (negative control). Quantitative ELISA detected a high concentration of anti-rHN-PorPV Immunoglobulin G (IgG) antibodies in sow sera after the second dose of vaccine administered on day 14 until farrowing, showing viral-neutralizing and cross-neutralization activity against different variants of PRV. Sera samples from piglets of immunized sows (with or without adjuvant), showed high concentrations of IgG antibodies. As expected, piglets from the negative control sow (n=5), exhibited severe signs of disease and 100% of mortality after PRV challenge study. Conversely, 75% and 87.5% of the piglets born from the rHN-PorPV and the rHN-PorPV-ISCOMs-immunized sows (n=8), survived, respectively, showing milder PRV clinical signs. Our data indicate that rHN-PorPV candidate vaccine produced in Escherichia coli induces efficient humoral response in pregnant sows and that the maternally derived immunity provides high protection to suckling piglets against PRV lethal challenge.

Dual-action of colloidal ISCOMs: an optimized approach using Box-Behnken design for the management of breast cancer.

Neuropeptide Y (NPY) occurs in G-protein-coupled receptors and offers targeted effects at the active sites for therapeutic action in various conditions like depression, stress, obesity and cancer. Immune stimulating complexes (ISCOMs) associate peptides with the lipid systems for enhancing antigen targeting to provide site-specific action and B-cell response. The present study focused on the encapsulation of NPY in ISCOMs to comprise dual action in the form of immunity modulation and management of breast cancer by arresting G0/G1 phase. The colloidal ISCOMs were prepared by coupling method and further optimized by Box-Behnken design of Design of Experiment (DoE) software. The NPY-loaded ISCOMs (formulation ISCN) were characterized by various parameters with higher % encapsulation efficiency of 87.99 ± 1.87% and in-vitro release of 84.16±3.2% of NPY for 24 h. The study of MTT assay on MCF-7 cell line for formulation ISCN exhibited a significant decrease in the cell growth of 66.41±4.7% at 10 µg/mL compared to plain NPY (52.21±0.04%). The MCF-7 cells showed a significant reduction in cytokine levels in the presence of formulation ISCN wherein TH1(TNF-α) and TH2(IL-10) levels were found to be 25.12±3.11 pg/mL and 35.76±4.23 pg/mL, respectively. The cell cycle study demonstrated that significant cells were blocked in the G0/G1 phase with 57.8±3.02% of cell apoptosis using formulation ISCN. The formulation ISCN was found to prolong t1/2 and increase AUC than plain NPY via intravenous administration due to complex formation with phospholipid. Hence, ISCOMs-based NPY system will be a promising approach for dual action as immunomodulation and anticancer effects by controlling the release of NPY.

Formulation of IMXQB: Nanoparticles Based on Quillaja brasiliensis Saponins to be Used as Vaccine Adjuvants.

Adjuvants are essential components of subunit, recombinant, nonreplicating and killed vaccines, as they are substances that boost, shape, and/or enhance the immune response triggered by vaccination. Saponins obtained from the Chilean Q. saponaria tree are used as vaccine adjuvants in commercial vaccines, although they are scarce and difficult to obtain. In addition, tree felling is needed during its extraction, which has ecological impact. Q. brasiliensis leaf-extracted saponins arise as a more sustainable alternative, although its use is still limited to preclinical studies. Despite the remarkable immunostimulating properties of saponins, they are toxic to mammalian cells, due to their intrinsic characteristics. For these reasons they are mostly used in veterinary vaccines, although recently the Q. saponaria purified saponin QS-21 has been included in adjuvant systems for human vaccines, such as Mosquirix and Shingrix (GSK). In order to abrogate the toxicity of the saponins fractions, they can be formulated as immunostimulating complexes (ISCOMs). ISCOM-matrices are cage-like nanoparticles of approximately 40 nm, formulated combining saponins and lipids, without antigen, and are great adjuvants able to promote Th1-biased immune responses in a safe manner. Herein we describe how to formulate ISCOM-matrices nanoparticles using Q. brasiliensis purified saponin fractions (IMXQB) by the dialysis method. In addition, we indicate how to verify the appropriate size and homogeneity of the formulated nanoparticles.

Zika Virus Envelope Domain III Recombinant Protein Delivered With Saponin-Based Nanoadjuvant From Quillaja brasiliensis Enhances Anti-Zika Immune Responses, Including Neutralizing Antibodies and Splenocyte Proliferation.

Nanoadjuvants that combine immunostimulatory properties and delivery systems reportedly bestow major improvements on the efficacy of recombinant, protein-based vaccines. Among these, self-assembled micellar formulations named ISCOMs (immune stimulating complexes) show a great ability to trigger powerful immunological responses against infectious pathogens. Here, a nanoadjuvant preparation, based on saponins from Quillaja brasiliensis, was evaluated together with an experimental Zika virus (ZIKV) vaccine (IQB80-zEDIII) and compared to an equivalent vaccine with alum as the standard adjuvant. The preparations were administered to mice in two doses (on days zero and 14) and immune responses were evaluated on day 28 post-priming. Serum levels of anti-Zika virus IgG, IgG1, IgG2b, IgG2c, IgG3 were significantly increased by the nanoadjuvant vaccine, compared to the mice that received the alum-adjuvanted vaccine or the unadjuvanted vaccine. In addition, a robust production of neutralizing antibodies and in vitro splenocyte proliferative responses were observed in mice immunized with IQB80-zEDIII nanoformulated vaccine. Therefore, the IQB80-zEDIII recombinant preparation seems to be a suitable candidate vaccine for ZIKV. Overall, this study identified saponin-based delivery systems as an adequate adjuvant for recombinant ZIKV vaccines and has important implications for recombinant protein-based vaccine formulations against other flaviviruses and possibly enveloped viruses.

Glomerulonefritis rápidamente progresiva mediada por inmunocomplejos (tipo II). Revisión de la literatura / Immune complex-mediated rapidly progressive glomerulonephritis (type II). Literature review

La glomerulonefritis rápidamente progresiva mediada por complejos inmunes (GMNRP II) es un síndrome clínico caracterizado por el rápido deterioro de la función renal asociado a hematuria, edemas y oliguria. Histológicamente se manifiesta como una glomerulonefritis crescéntica, con la presencia de depósitos granulares en la inmunofluorescencia. Aunque es una enfermedad rara, es grave y puede evolucionar a una enfermedad renal crónica, por lo cual es fundamental su identificación temprana. A continuación, se presenta una revisión sobre este tipo de glomerulonefritis, con énfasis en su etiología y en las opciones terapéuticas existentes en la actualidad

Rapidly progressive immune complex-mediated glomerulonephritis (RPGNMN II) is a clinical syndrome characterized by severe deterioration of renal function associated with hematuria, edema, and oliguria. It is histologically characterized as a crescentic glomerulonephritis, with the presence of granular deposits on immunofluorescence. Although it is a rare condition, it is a potentially serious disease that may progress to chronic renal disease, therefore its early identification is essential. Here we present a review of this form of glomerulonephritis, with emphasis on its etiology and the currently available therapeutic options

Inmunocomplejos circulantes en el lupus eritematoso sistémico / Circulating immunocomplexes in systemic erythematous lupus

Introducción: Los biomarcadores son claves en el diagnóstico y pronóstico del lupus eritematoso sistémico en el cual las manifestaciones clínicas son extremadamente complejas y heterogéneas. Objetivo: Determinar el valor clínico de los inmunocomplejos circulantes en pacientes con lupus eritematosos sistémico. Métodos: Se determinaron los niveles séricos de inmunocomplejos fijadores del C1q y de los anticuerpos anti-ácido desoxirribonucleico de doble cadena (anti-ADNdc), anti-nucleosoma (anti-Nuc) y anti-proteínas ribosomales (anti-RibP) por el ensayo inmuno-adsorbente ligado a enzima (ELISA) en 93 pacientes con diagnóstico de lupus eritematosos sistémico. Se utilizaron exámenes no paramétricos para probar la asociación entre los inmunocomplejos y los auto-anticuerpos. La frecuencia de nefritis lupica en los grupos de pacientes positivos y negativos de inmunocomplejos circulantes se comparó mediante Chi cuadrado. Resultados: Los inmunocomplejos se encontraron en 24 (25,8 por ciento) pacientes con lupus eritematosos sistémico. Los pacientes que presentaron los títulos más altos de inmunocomplejos fueron los positivos a los tres auto-anticuerpos usados (p=0,044). Se encontró correlación directa entre los niveles de anti-RibP y los inmunocomplejos (Rho=0,303, p=0,003) y entre los anti-ADNdc y anti-Nuc (Rho=0,449, p=0,001). La nefritis lúpica se presentó en 58,3 por ciento de pacientes con inmunocomplejos, y 31,9 por ciento pacientes negativos de inmunocomplejos (p=0,213). Conclusiones: Los inmunocomplejos circulantes caracterizaron una fracción menor de pacientes con lupus eritematosos sistémico. La presencia de estos no se asoció a los anticuerpos anti-ADNdc ni a la nefritis lupica(AU)

Introduction: Biomarkers are essential in the diagnosis and prognosis of systemic erythematous lupus in which clinical manifestations are extremely complex and heterogeneous. Objective: To determine the clinical value of circulating immunocomplexes in patients with systemic erythematous lupus. Methods: Serum levels of C1q-binding immunocomplexes and anti-double-stranded deoxyribonucleic acid (anti-dsDNA), anti-nucleosome (anti-Nuc) and anti-ribosomal proteins (anti-RibP) were determined by enzyme-linked immunosorbent assay (ELISA) in 93 patients diagnosed with systemic lupus erythematosus. Nonparametric tests were used to test the association between immunocomplexes and auto-antibodies. The frequency of lupus nephritis in the circulating immunocomplex positive and negative patient groups was compared using Chi square. Results: Immunocomplexes were found in 24 (25.8 percent) patients with systemic lupus erythematosus. The patients with the highest immunocomplex titers were positive for the three autoantibodies used (p = 0.044). A direct correlation was found between the levels of anti-RibP and immunocomplexes (Rho = 0.303, p = 0.003) and between anti-dsDNA and anti-Nuc (Rho = 0.449, p = 0.001). Lupus nephritis occurred in 58.3 percent of immunocomplex patients, and 31.9 percent immunocomplex negative patients (p = 0.213). Conclusions: Circulating immunocomplexes characterized a smaller fraction of patients with systemic lupus erythematosus. Their presence was not associated with anti-dsDNA antibodies or lupus nephritis(AU)

Saponins from Quillaja saponaria and Quillaja brasiliensis: Particular Chemical Characteristics and Biological Activities.

Quillaja saponaria Molina represents the main source of saponins for industrial applications. Q. saponaria triterpenoids have been studied for more than four decades and their relevance is due to their biological activities, especially as a vaccine adjuvant and immunostimulant, which have led to important research in the field of vaccine development. These saponins, alone or incorporated into immunostimulating complexes (ISCOMs), are able to modulate immunity by increasing antigen uptake, stimulating cytotoxic T lymphocyte production (Th1) and cytokines (Th2) in response to different antigens. Furthermore, antiviral, antifungal, antibacterial, antiparasitic, and antitumor activities are also reported as important biological properties of Quillaja triterpenoids. Recently, other saponins from Q. brasiliensis (A. St.-Hill. & Tul.) Mart. were successfully tested and showed similar chemical and biological properties to those of Q. saponaria barks. The aim of this manuscript is to summarize the current advances in phytochemical and pharmacological knowledge of saponins from Quillaja plants, including the particular chemical characteristics of these triterpenoids. The potential applications of Quillaja saponins to stimulate further drug discovery research will be provided.

Recombinant Fusion Protein Joining E Protein Domain III of Tick-Borne Encephalitis Virus and HSP70 of Yersinia pseudotuberculosis as an Antigen for the TI-Complexes.

Domain III (DIII) of the tick-borne encephalitis virus (TBEV) protein E contains epitopes, which induce antibodies capable of neutralizing the virus. To enhance the immunogenicity of this protein, which has a low molecular weight, the aim of the present work was to express, isolate, and characterize a chimeric protein based on the fusion of the bacterial chaperone HSP70 of Yersinia pseudotuberculosis and EIII (DIII + stem) as a prospective antigen for an adjuvanted delivery system, the tubular immunostimulating complex (TI-complex). The chimeric construction was obtained using pET-40b(+) vector by ligating the respective genes. The resulting plasmid was transformed into DE3 cells for the heterologous expression of the chimeric protein, which was purified by immobilized metal affinity chromatography (IMAC). ELISA, differential scanning calorimetry, intrinsic fluorescence, and computational analysis were applied for the characterization of the immunogenicity and conformation of the chimeric protein. Mice immunization showed that the chimeric protein induced twice the number of anti-EIII antibodies in comparison with EIII alone. In turn, the incorporation of the HSP70/EIII chimeric protein in the TI-complex resulted in a twofold increase in its immunogenicity. The formation of this vaccine construction was accompanied by significant conformational changes in the chimeric protein. Using HSP70 in the content of the chimeric protein represents an efficient means for presenting the main antigenic domain of the TBEV envelope protein to the immune system, whereas the incorporation of this chimeric protein into the TI-complex further contributes to the development of a stronger immune response against the TBEV infection.

Nanoparticulate Tubular Immunostimulating Complexes: Novel Formulation of Effective Adjuvants and Antigen Delivery Systems.

New generation vaccines, based on isolated antigens, are safer than traditional ones, comprising the whole pathogen. However, major part of purified antigens has weak immunogenicity. Therefore, elaboration of new adjuvants, more effective and safe, is an urgent problem of vaccinology. Tubular immunostimulating complexes (TI-complexes) are a new type of nanoparticulate antigen delivery systems with adjuvant activity. TI-complexes consist of cholesterol and compounds isolated from marine hydrobionts: cucumarioside A2-2 (CDA) from Cucumaria japonica and monogalactosyldiacylglycerol (MGDG) from marine algae or seagrass. These components were selected due to immunomodulatory and other biological activities. Glycolipid MGDG from marine macrophytes comprises a high level of polyunsaturated fatty acids (PUFAs), which demonstrate immunomodulatory properties. CDA is a well-characterized individual compound capable of forming stable complex with cholesterol. Such complexes do not possess hemolytic activity. Ultralow doses of cucumariosides stimulate cell as well as humoral immunity. Therefore, TI-complexes comprising biologically active components turned out to be more effective than the strongest adjuvants: immunostimulating complexes (ISCOMs) and complete Freund's adjuvant. In the present review, we discuss results published in series of our articles on elaboration, qualitative and quantitative composition, ultrastructure, and immunostimulating activity of TI-complexes. The review allows immersion in the history of creating TI-complexes.

Functionalized immunostimulating complexes with protein A via lipid vinyl sulfones to deliver cancer drugs to trastuzumab-resistant HER2-overexpressing breast cancer cells.

BACKGROUND: Around 20%-30% of breast cancers overexpress the proto-oncogene human epidermal growth receptor 2 (HER2), and they are characterized by being very invasive. Therefore, many current studies are focused on testing new therapies against tumors that overexpress this receptor. In particular, there exists major interest in new strategies to fight breast cancer resistant to trastuzumab (Tmab), a humanized antibody that binds specifically to HER2 interfering with its mitogenic signaling. Our team has previously developed immunostimulating complexes (ISCOMs) as nanocapsules functionalized with lipid vinyl sulfones, which can incorporate protein A and bind to G immunoglobulins that makes them very flexible nanocarriers. METHODS AND RESULTS: The aim of this in vitro study was to synthesize and evaluate a drug delivery system based on protein A-functionalized ISCOMs to target HER2-overexpressing cells. We describe the preparation of ISCOMs, the loading with the drugs doxorubicin and paclitaxel, the binding of ISCOMs to alkyl vinyl sulfone-protein A, the coupling of Tmab, and the evaluation in both HER2-overexpressing breast cancer cells (HCC1954) and non-overexpressing cells (MCF-7) by flow cytometry and fluorescence microscopy. Results show that the uptake is dependent on the level of overexpression of HER2, and the analysis of the cell viability reveals that targeted drugs are selective toward HCC1954, whereas MCF-7 cells remain unaffected. CONCLUSION: Protein A-functionalized ISCOMs are versatile carriers that can be coupled to antibodies that act as targeting agents to deliver drugs. When coupling to Tmab and loading with paclitaxel or doxorubicin, they become efficient vehicles for the selective delivery of the drug to Tmab-resistant HER2-overexpressing breast cancer cells. These nanoparticles may pave the way for the development of novel therapies for poor prognosis resistant patients.

Saponin Interactions with Model Membrane Systems - Langmuir Monolayer Studies, Hemolysis and Formation of ISCOMs.

Saponins are used in medicine due to their pharmacological and immunological effects. To better understand interactions of saponins with model membranes and natural membranes of, for example, erythrocytes, Langmuir film balance experiments are well established. For most saponins, a strong interaction with cholesterol was demonstrated in dependence of both the aglycone part and the sugar moieties and is suggested to be correlated with a strong hemolytic activity, high toxicity, and high surface activity, as was demonstrated for the steroid saponin digitonin. In general, changes in the sugar chain or in substituents of the aglycone result in a modification of the saponin properties. A promising saponin with regard to fairly low hemolytic activity and high adjuvant effect is α-tomatine, which still shows a high affinity for cholesterol. An interaction with cholesterol and lipids has also been proven for the Quillaja saponin from the bark of Quillaja saponaria Molina. This triterpene saponin was approved in marketed vaccines as an adjuvant due to the formation of immunostimulating complexes. Immunostimulating complexes consist of a Quillaja saponin, cholesterol, phospholipids, and a corresponding antigen. Recently, another saponin from Quillaja brasiliensis was successfully tested in immunostimulating complexes, too. Based on the results of interaction studies, the formation of drug delivery systems such as immunostimulating complexes or similar self-assembled colloids is postulated for a variety of saponins.

An Updated Review of ISCOMSTM and ISCOMATRIXTM Vaccines.

The need for the improvement of vaccine potency as well as reducing toxicity in healthy recipients has motivated studies of the formulation of vaccines regarding control of how, when, and where antigens and adjuvants encounter immune cells and other cells/tissues following vaccine administration. Immunostimulatory complexes (ISCOMs) and ISCOMATRIXTM adjuvants are versatile and flexible systems with various phospholipids and saponin components. They are being used in novel vaccines for either infectious diseases or cancer. This article presents a brief review of the latest developments using such adjuvants and possible new applications.

[Current status and future prospects in HMGB1 and receptor researches].

High mobility group box protein1 (HMGB1), a ubiquitous chromatin component, is released by necrotic cells, apoptotic cells, and cells in profound distress. HMGB1 plays a critical role as a proinflammatory mediator. HMGB1 represents an important new target for drug development in a variety of inflammatory disorders, including stroke, brain injury, arteriosclerosis, and cancer. The antibodies against HMGB1 and its receptors ar hopeful candidates for immunotherapeutic strategy for treating patients with these diseases. HMGB1 forms immunostimulatory complexes by interaction with cytokines and other endogenous or exogenous factors. The HMGB1-partner molecule complexes can enhance the immune response induced by the ligand alone. The current status of HMGB1 works is summarized and future prospects will be provided in this review.

Novel ISCOMs from Quillaja brasiliensis saponins induce mucosal and systemic antibody production, T-cell responses and improved antigen uptake.

In the last decades, significant efforts have been dedicated to the search for novel vaccine adjuvants. In this regard, saponins and its formulations as "immunostimulating complexes" (ISCOMs) have shown to be capable of stimulating potent humoral and cellular immune responses, enhanced cytokine production and activation of cytotoxic T cells. The immunological activity of ISCOMs formulated with a saponin fraction extracted from Quillaja brasiliensis (QB-90 fraction) as an alternative to classical ISCOMs based on Quil A(®) (IQA) is presented here. The ISCOMs prepared with QB-90, named IQB-90, typically consist of 40-50 nm, spherical, cage-like particles, built up by QB-90, cholesterol, phospholipids and antigen (ovalbumin, OVA). These nanoparticles were efficiently uptaken in vitro by murine bone marrow-derived dendritic cells. Subcutaneously inoculated IQB-90 induced strong serum antibody responses encompassing specific IgG1 and IgG2a, robust DTH reactions, significant T cell proliferation and increases in Th1 (IFN-γ and IL-2) cytokine responses. Intranasally delivered IQB-90 elicited serum IgG and IgG1, and mucosal IgA responses at distal systemic sites (nasal passages, large intestine and vaginal lumen). These results indicate that IQB-90 is a promising alternative to classic ISCOMs as vaccine adjuvants, capable of enhancing humoral and cellular immunity to levels comparable to those induced by ISCOMs manufactured with Quillaja saponaria saponins.

Mucosal vaccination against tuberculosis using Ag85A-loaded immunostimulating complexes.

Tuberculosis (TB) is one of the major devastating diseases in the world, mainly caused by Mycobacterium tuberculosis. Furthermore, multi-drug resistant TB and extremely drug resistant TB are becoming big problems globally. Bacillus Calmette-Guerin (BCG) is the only available vaccine which provides protection against TB. The BCG vaccine is effective in children but not recommended in adults and elderly patients due to an associated low risk of infection with Mycobacterium tuberculosis and variable effectiveness of the vaccine. The main aim of this research study is to develop such a vaccine which will provide a better and safer profile in children and adults, as well as in elderly patients. In this present study, we prepared pulmonary tubercular vaccine by using an Antigen 85 complex (Ag85)-loaded nanocarrier such as the immunostimulating complex (ISCOM). Immunological outcomes clearly indicated significant improvement in humoral as well as cellular immune responses after pulmonary immunization with ISCOMs containing Quil A in mice.

Immune response and functional role of antibodies raised in heifers against a Staphylococcus aureus CP5 lysate and recombinant antigens vaccine formulated with Iscom Matrix adjuvant.

Staphylococcus aureus is the most frequently isolated pathogen from bovine intramammary infections worldwide. Commercially available vaccines for mastitis control are composed either of S. aureus lysates or inactivated whole-cells formulated with traditional adjuvants. We recently showed the ability of a S. aureus CP5 lysate vaccine adjuvanted with Iscom Matrix to generate a longer lasting specific antibody response in blood and milk, with improved opsonic capacity, compared with a S. aureus CP5 whole-cell formulation. The aim of the present study was to obtain an experimental immunogen composed of lysed cells of a CP5 S. aureus strain supplemented with recombinant clumping factor A, fibronectin binding protein A and ß-toxin formulated with Iscom Matrix, characterize the immune response generated when immunizing pregnant heifers and assess the functional role of antibodies raised against this immunogen in experimental models. Both a lysate vaccine and a lysate+recombinant antigens vaccine elicited antibodies that promoted neutrophil phagocytosis and inhibited internalization into mammary epithelial cells, in vitro. Incorporation of defined antigenic molecules to the lysate formulation elicited a strong specific humoral immune response against both lysate and recombinant antigens and was associated with higher expression of regulatory and pro-inflammatory cytokines. In addition, antibodies were efficient for blocking S. aureus binding to bovine fibrinogen and fibronectin, and neutralizing ß-toxin effect in vitro, placing these antigens as candidates to be included in a formulation directed to prevent staphylococcal bovine mastitis.

A Neospora caninum vaccine using recombinant proteins fails to prevent foetal infection in pregnant cattle after experimental intravenous challenge.

The aim of the present study was to evaluate the immunogenicity and protective efficacy of rNcSAG1, rNcHSP20 and rNcGRA7 recombinant proteins formulated with immune stimulating complexes (ISCOMs) in pregnant heifers against vertical transmission of Neospora caninum. Twelve pregnant heifers were divided into 3 groups of 4 heifers each, receiving different formulations before mating. Immunogens were administered twice subcutaneously: group A animals were inoculated with three recombinant proteins (rNcSAG1, rNcHSP20, rNcGRA7) formulated with ISCOMs; group B animals received ISCOM-MATRIX (without antigen) and group C received sterile phosphate-buffered saline (PBS) only. The recombinant proteins were expressed in Escherichia coli and purified nickel resin. All groups were intravenously challenged with the NC-1 strain of N. caninum at Day 70 of gestation and dams slaughtered at week 17 of the experiment. Heifers from group A developed specific antibodies against rNcSAG1, rNcHSP20 and rNcGRA7 prior to the challenge. Following immunization, an statistically significant increase of antibodies against rNcSAG1 and rNcHSP20 in all animals of group A was detected compared to animals in groups B and C at weeks 5, 13 and 16 (P<0.001). Levels of antibodies against rNcGRA7 were statistical higher in group A animals when compared with groups B and C at weeks 5 and 16 (P>0.001). There were no differences in IFN-γ production among the experimental groups at any time point (P>0.05). Transplacental transmission was determined in all foetuses of groups A, B and C by Western blot, immunohistochemistry and nested PCR. This work showed that rNcSAG1, rNcHSP20 and rNcGRA7 proteins while immunogenic in cattle failed to prevent the foetal infection in pregnant cattle challenged at Day 70 of gestation.