Specific Immune Responses In Mice Research Articles

A peptide from the Japanese encephalitis virus failed to induce the production of anti-N-methyl-d-aspartate receptor antibodies via molecular mimicry in mice

BackgroundThe development of anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis following viral encephalitis, such as Japanese encephalitis, has received increasing attention in recent years. However, the mechanism of anti-NMDAR antibody production following Japanese encephalitis has not been explored. MethodsA peptide from the Japanese encephalitis virus (JEV), which shares a similar amino acid sequence with GluN1, was identified by sequence comparison. We then explored whether active subcutaneous immunization with the JEV peptide could induce the production of anti-NMDAR antibodies and related pathophysiological and behavioral changes in mice. In addition, a published active immune model of anti-NMDAR encephalitis using a GluN1 peptide was used as the positive control. ResultsA 6-amino-acid sequence with 83 % similarity between the envelope protein of the JEV (HGTVVI) and GluN1 (NGTHVI) was identified, and the sequence included the N368/G369 region. Active immunization with the JEV peptide induced a substantial and specific immune response in mice. However, anti-NMDAR antibodies were not detected in the serum of mice immunized with the JEV peptide by ELISA, CBA, and TBA. Moreover, mice immunized with the JEV peptide presented no abnormities related to anti-NMDAR antibodies according to western blotting, patch clamp, and a series of behavioral tests. In addition, active immunization with a recently reported GluN1 peptide failed to induce anti-NMDAR antibody production in mice. ConclusionsIn this study, the attempt of active immunization with the JEV peptide to induce the production of anti-NMDAR antibodies via molecular mimicry failed. The pathogenesis of anti-NMDAR encephalitis following Japanese encephalitis remains to be elucidated.

The Effect Recearch of Laser Radiation with
 Wavelenght 1270 nm on the Specific Binding of IgG to S. Aureus Antigens and on the Ability of Staphylococcal Enterotoxin A to Induce a Specific Immune Response in Mice

Relevance: Recently, laser radiation in the near infrared region of the spectrum has been increasingly used in medicine, coinciding with the absorption bands of endogenous molecular oxygen for the purpose of direct optical generation of its active form – singlet oxygen (light-oxygen effect). However, the mechanisms of its manifestation and interaction with biological objects have not been fully elucidated.
 Clarifying them is relevant and can serve as a basis for expanding clinical application.
 Purpose: To study the effect of laser radiation with l~1270 nm on the specific binding of IgG to antigens and the ability of staphylococcal enterotoxin to induce an immune response.
 The objectives of the work are to determine the exposure doses that can affect this process and to establish the very fact of this possibility.
 Materials and methods: Experimental laser device l~1270 nm (New Surgical Technologies, Moscow), staphylococcal antigen, staphylococcal enterotoxin A, blood serum of immunized mice.
 Results: Establishment of the fact of suppression of the antigen + antibody reaction in vitro, both during antigen irradiation and serum irradiation, as well as suppression of the ability of the irradiated enterotoxin to cause an immune response.
 Conclusion: Suppression of immune reactions under the influence of laser radiation with the listed substrates has been established, which may indirectly indicate the influence of singlet oxygen on the conformational structure of protein molecules. This fact is important for understanding one of the ways to implement the “light-oxygen effect” and can be used in the clinic.

Immunomodulatory Activity of Kasumba Turate (Carthamus tinctorius L.) Extract Against Non-Specific and Specific Immune Responses in Mice

Immunomodulators are compounds that can regulate the immune system with the objective of normalizing or helping to optimize the immune system. People tend to back to nature by utilizing various plants to be used as medicine, one of which is kasumba turate (Carthamus tinctorius L.) which is thought to be efficacious as an immunomodulator in increasing the activity and capacity of macrophages. This study aims to determine the immunomodulatory activity of kasumba turate ethanol (CTEE) extract against non-specific and specific immune responses in mice. Non-specific immune response tests using the carbon clearance method were carried out on mice with 3 dose ratings. Specific immune response tests were carried out by the hemagglutination test method to determine antibody titers. The results of the carbon clearance test showed that the CTEE dose 50 mg/KgBW was a moderate immunostimulant with a phagocytic index of 1.41, while doses of 100 and 200 mg/KgBW were strong immunostimulants with phagocytic index of 1.57 and 1.82 respectively. While the results of the hemagglutination test method, the antibody titers value is determined from the highest serum dilution value that still indicates hemagglutination. The results show an increase in humoral immune response with the highest primary and secondary antibody titer values of 1:256 and 1:1024 for doses of 100 mg/KgBW, and 1:512 and 1:1024 for doses of 200 mg/KgBW. Phytochemical screening results of CTEE proved to contain alkaloid group compounds, flavonoids, saponins, tannins and triterpenoids. Based on the results obtained, it was concluded that the administration of CTEE showed immunostimulant activity.

Adenovirus Vaccine Containing Truncated SARS-CoV-2 Spike Protein S1 Subunit Leads to a Specific Immune Response in Mice.

The development of an efficient and safe coronavirus disease 2019 (COVID-19) vaccine is a crucial approach for managing the severe acute respiratory disease coronavirus 2 (SARS-CoV-2) pandemic in light of current conditions. In this study, we produced a shortened segment of the optimized SARS-CoV-2 spike gene (2043 bp, termed S1) that was able to encode a truncated S1 protein. The protein was tested to determine if it could elicit efficient immunization in mice against SARS-CoV-2. The presence of the S1 protein was confirmed with immunofluorescence and Western blotting. An adenovirus vaccine bearing the S1 gene fragment (Ad-S1) was administered intramuscularly to mice four times over 4 weeks. SARS-CoV-2 S1 protein humoral immunity was demonstrated in all immunized mice. The serum from immunized mice demonstrated excellent anti-infection activity in vitro. A robust humoral immune response against SARS-CoV-2 was observed in the mice after vaccination with Ad-S1, suggesting that the adenovirus vaccine may aid the development of vaccines against SARS-CoV-2 and other genetically distinct viruses.

Immune Response after Skin Delivery of a Recombinant Heat-Labile Enterotoxin B Subunit of Enterotoxigenic Escherichia coli in Mice.

Enterotoxigenic Escherichia coli (ETEC) infections have been identified as a major cause of acute diarrhoea in children in developing countries, associated with substantial morbidity and mortality rates. Additionally, ETEC remains the most common cause of acute diarrhea of international travellers to endemic areas. The heat-labile toxin (LT) is a major virulence factor of ETEC, with a significant correlation between the presence of antibodies against LT and protection in infected patients. In the present work, we constructed a recombinant LTB unit (rLTB) and studied the capacity of this toxoid incorporated in microneedles (rLTB-MN) to induce a specific immune response in mice. MN were prepared from aqueous blends of the polymer Gantrez AN® [poly (methyl vinyl ether-co-maleic anhydride)], which is not cytotoxic and has been shown to possess immunoadjuvant properties. The mechanical and dissolution properties of rLTB-MNs were evaluated in an in vitro Parafilm M® model and in mice and pig skin ex vivo models. The needle insertion ranged between 378 µm and 504 µm in Parafilm layers, and MNs fully dissolved within 15 min of application inside porcine skin. Moreover, female and male BALB/c mice were immunized through ear skin with one single dose of 5 μg·rLTB in MNs, eliciting significant fecal anti-LT IgA antibodies, higher in female than in male mice. Moreover, we observed an enhanced production of IL-17A by spleen cells in the immunized female mice, indicating a mucosal non-inflammatory and neutralizing mediated response. Further experiments will now be required to validate the protective capacity of this new rLTB-MN formulation against this deadly non-vaccine-preventable disease.

Construction and Evaluation of the Brucella Double Gene Knock-out Vaccine Strain MB6 Δbp26ΔwboA (RM6)

Objective: Brucellosis is a serious zoonotic infection worldwide. To date, vaccination is the most effective measure against brucellosis. This study was aimed at obtaining a vaccine strain that has high protective efficacy and low toxicity, and allows vaccination to be differentiated from infection. Methods: Using homologous recombination, we constructed a double gene-deletion Brucella strain MB6 Δbp26ΔwboA (RM6) and evaluated its characteristics, safety and efficacy. Results: The RM6 strain had good proliferative ability and stable biological characteristics in vivo and in vitro. Moreover, it had a favorable safety profile and elicited specific immune responses in mice and sheep. Conclusion: The RM6 strain may have substantial practical application value.

Generation of Bacillus subtilis displaying alpha-toxin HlaH35LH48L fused with CotB and CotG, and studying the immune response in mice

Introduction: The Bacillus subtilis spore is considered to be a powerful vehicle for surface display and antigen delivery. Being safe and widely used for the purpose of oral bacteriotherapy in humans and animals, B. subtilis spore has potential in the domain of needle-free vaccine development. The spores themselves also behave as an adjuvant. This study aims to generate B. subtilis spores expressing mutant staphylococcal alpha-toxin HlaH35LH48L on the surface and to study their ability to evoke a specific immune response in mice. Methods: Vectors carrying the hlaH35LH48L gene fused with the coding genes of anchor proteins, cotB and cotG, were cloned in E. coli before being transformed into B. subtilis. The generation of the B. subtilis new strains via chromosomal integration was confirmed by PCR. Sporulation was observed under the microscope. The expression of the target protein on the spore surface was determined by sporeELISA. The level of IgG in the serum and IgA in the feces of Swiss mice were analyzed using ELISA to learn about the immune response against the B. subtilis spore administrated via the oral route. Results: The PCR products of an expected size on agarose gel electrophoresis showed successful integration, resulting in the construction of new B. subtilis strains BsHT2331 and BsHT2334. sporeELISA analysis detected a significant HlaH35LH48L expression on the spore surface. The BsHT2331 spores (CotB-HlaH35LH48L) triggered a constant increase in the IgG and IgA levels in mice after three doses as 5.5-fold and 2.5-fold higher than the pre-immunization, respectively (p-value < 0.0001). Meanwhile, the group of mice orally administrated with BsHT2334 (CotG-HlaH35LH48L) showed a notable IgG titer but minor IgA response. Conclusion: The results concluded that the construction of two new strains BsHT2331 and BsHT2334 that used spore coat proteins CotB and CotG to display mutant alpha-toxin HlaH35LH48L on the B. subtilis spore surface was successful. It provided an assessment of the ability of B. subtilis spores to stimulate specific antibody production in mice.

Safety and efficacy of RNA vaccines: State of the art

This review describes principles of action and the method of delivery of mRNA molecules into cells, as well as some of developed RNA vaccines and the results obtained in their study, though they have not been authorized for use yet. In addition, the review discusses efficacy and safety proved for RNA vaccines registered for COVID-19 prevention at the time of writing. The development, clinical trials and market launch of RNA vaccines for mass immunization in a few months can be considered one of the major breakthroughs in pharmacology over the past year. Despite of all seemingly indisputable advantages, none of RNA vaccines had reached Phase III of clinical trials since the moment of its discovery in 1993 until last year. The first experience of the successful use of mRNA vaccines was back in the 90s of the last century, when vaccination of mice with liposomes encoding an antigen-encoding mRNA was found to initiate specific immune response in mice. However, in these years, the method did not find application, due to the toxicity of lipids used. Subsequently, a large number of attempts have been made to develop vaccines against other viral infections, including Zika virus, Dengue virus, Ebola virus, cytomegalovirus, influenza virus and others. Despite the importance for preventing the spread of these diseases, the development of a vaccine preparation is a rather lengthy process, and final success is not guaranteed. However, the COVID-19 pandemic has become speeded the development of mRNA vaccines up.At the time of writing the review, two mRNA-based vaccines have been registered only in the world, both, BNT162b2 and mRNA-1273, were against COVID-19. Their effectiveness and safety are still actively studied. Moreover, it took less than a year for new strains of SARS-CoV-2 to appear, and the efficiency of vaccines against them was found to be lower than against the reference pathogen variant. Considering that the three new strains of SARS-CoV-2, “British”, “African” and “Brazilian”, are rapidly spreading in the world, the first results of efficiency evaluation of vaccines against them have already been published. One may expect that, considering mutations in these strains, the BNT162b2 and mRNA-1273 vaccines will remain effective against the “British” strain, but their protective properties are greatly weakened against the “African” variant.

In Vivo Sustained Release of Peptide Vaccine Mediated by Dendritic Mesoporous Silica Nanocarriers.

Mesoporous silica nanoparticles have drawn increasing attention as promising candidates in vaccine delivery. Previous studies evaluating silica-based vaccine delivery systems concentrated largely on macromolecular antigens, such as inactivated whole viruses. In this study, we synthesized dendritic mesoporous silica nanoparticles (DMSNs), and we evaluated their effectiveness as delivery platforms for peptide-based subunit vaccines. We encapsulated and tested in vivo an earlier reported foot-and-mouth disease virus (FMDV) peptide vaccine (B2T). The B2T@DMSNs formulation contained the peptide vaccine and the DMSNs without further need of other compounds neither adjuvants nor emulsions. We measured in vitro a sustained release up to 930 h. B2T@DMSNs-57 and B2T@DMSNs-156 released 23.7% (135 µg) and 22.8% (132 µg) of the total B2T. The formation of a corona of serum proteins around the DMSNs increased the B2T release up to 61% (348 µg/mg) and 80% (464 µg/mg) for B2T@DMSNs-57 and B2T@DMSNs-156. In vitro results point out to a longer sustained release, assisted by the formation of a protein corona around DMSNs, compared to the reference formulation (i.e., B2T emulsified in Montanide). We further confirmed in vivo immunogenicity of B2T@DMSNs in a particle size-dependent manner. Since B2T@DMSNs elicited specific immune responses in mice with high IgG production like the reference B2T@Montanide™, self-adjuvant properties of the DMSNs could be ascribed. Our results display DMSNs as efficacious nanocarriers for peptide-based vaccine administration.

A Chimeric Sudan Virus-Like Particle Vaccine Candidate Produced by a Recombinant Baculovirus System Induces Specific Immune Responses in Mice and Horses.

Ebola virus infections lead to severe hemorrhagic fevers in humans and nonhuman primates; and human fatality rates are as high as 67%–90%. Since the Ebola virus was discovered in 1976, the only available treatments have been medical support or the emergency administration of experimental drugs. The absence of licensed vaccines and drugs against the Ebola virus impedes the prevention of viral infection. In this study, we generated recombinant baculoviruses (rBV) expressing the Sudan virus (SUDV) matrix structural protein (VP40) (rBV-VP40-VP40) or the SUDV glycoprotein (GP) (rBV-GP-GP), and SUDV virus-like particles (VLPs) were produced by co-infection of Sf9 cells with rBV-SUDV-VP40 and rBV-SUDV-GP. The expression of SUDV VP40 and GP in SUDV VLPs was demonstrated by IFA and Western blot analysis. Electron microscopy results demonstrated that SUDV VLPs had a filamentous morphology. The immunogenicity of SUDV VLPs produced in insect cells was evaluated by the immunization of mice. The analysis of antibody responses showed that mice vaccinated with SUDV VLPs and the adjuvant Montanide ISA 201 produced SUDV GP-specific IgG antibodies. Sera from SUDV VLP-immunized mice were able to block infection by SUDV GP pseudotyped HIV, indicating that a neutralizing antibody against the SUDV GP protein was produced. Furthermore, the activation of B cells in the group immunized with VLPs mixed with Montanide ISA 201 was significant one week after the primary immunization. Vaccination with the SUDV VLPs markedly increased the frequency of antigen-specific cells secreting type 1 and type 2 cytokines. To study the therapeutic effects of SUDV antibodies, horses were immunized with SUDV VLPs emulsified in Freund’s complete adjuvant or Freund’s incomplete adjuvant. The results showed that horses could produce SUDV GP-specific antibodies and neutralizing antibodies. These results showed that SUDV VLPs demonstrate excellent immunogenicity and represent a promising approach for vaccine development against SUDV infection. Further, these horse anti-SUDV purified immunoglobulins lay a foundation for SUDV therapeutic drug research.

Inactivated Lactobacillus plantarum Carrying a Surface-Displayed Ag85B-ESAT-6 Fusion Antigen as a Booster Vaccine Against Mycobacterium tuberculosis Infection.

Vaccination is considered the most effective strategy for controlling tuberculosis (TB). The existing vaccine, the Bacille Calmette-Guérin (BCG), although partially protective, has a number of limitations. Therefore, there is a need for developing new TB vaccines and several strategies are currently exploited including the use of viral and bacterial delivery vectors. We have previously shown that Lactobacillus plantarum (Lp) producing Ag85B and ESAT-6 antigens fused to a dendritic cell-targeting peptide (referred to as Lp_DC) induced specific immune responses in mice. Here, we analyzed the ability of two Lp-based vaccines, Lp_DC and Lp_HBD (in which the DC-binding peptide was replaced by an HBD-domain directing the antigen to non-phagocytic cells) to activate antigen-presenting cells, induce specific immunity and protect mice from Mycobacterium tuberculosis infection. We tested two strategies: (i) Lp as BCG boosting vaccine (a heterologous regimen comprising parenteral BCG immunization followed by intranasal Lp boost), and (ii) Lp as primary vaccine (a homologous regimen including subcutaneous priming followed by intranasal boost). The results showed that both Lp constructs applied as a BCG boost induced specific cellular immunity, manifested in T cell proliferation, antigen-specific IFN-γ responses and multifunctional T cells phenotypes. More importantly, intranasal boost with Lp_DC or Lp_HBD enhanced protection offered by BCG, as shown by reduced M. tuberculosis counts in lungs. These findings suggest that Lp constructs could be developed as a potential mucosal vaccine platform against mycobacterial infections.

Staphylococcal enterotoxin C2 as an adjuvant for rabies vaccine induces specific immune responses in mice.

Rabies vaccine administration is the most effective method to prevent the occurrence of rabies disease. However, administration of rabies vaccine without adjuvant always shows low efficiency. As a member of superantigen, staphylococcal enterotoxin C2 (SEC2) non-specifically activates T-cells at extremely low concentration. It enlightens us that SEC2 may be used as an adjuvant. We carried out the experiment that the mice received twice immunization with rabies vaccine in the presence or absence of SEC2 at 1-week interval. Serum and splenocytes from immunized mice were collected to measure the level of rabies-specific-IgG and the cell that secretes IFN-γ or IL-4. The promotion of antigen-specific splenocytes proliferation was also detected. Besides, a challenge test was performed to evaluate the protective efficiency of SEC2. It was shown that mice immunized with vaccine combined with SEC2 generated more specific anti-rabies-antibodies. The results for production of IFN-γ and IL-4, as well as the proliferation of splenocytes from immunized mice indicated SEC2 promoted the specific immune responses induced by rabies vaccine. Moreover, immunization of mice with vaccine combined with SEC2 provided efficient protection against the lethal rabies exposure. Taken together, our findings indicated that SEC2 can be served as an adjuvant for rabies vaccines.

Specific immune responses in mice following subchronic exposure to acetamiprid

AimsAcetamiprid (ACE) is an insecticide of the neonicotinoid family, the most widely used in the world. Herein, we assessed the effect of ACE on either the humoral or cellular immune responses of rodents. We also evaluated the role of curcumin in the restoration of altered immune responses after ACE treatment. MethodsFive groups of five Swiss Albino mice were immunized intraperitoneally with the recombinant form of CFP32, a virulence factor of Mycobacterium tuberculosis. One group received ACE (5mg/kg) during 61days, a second one received ACE associated with curcumin (100mg/kg). Three control groups were included; one untreated, the second received corn oil and the third received curcumin alone. The humoral immune response was assessed by ELISA testing the anti-rCFP32 antibody concentrations in the serum. The cellular immune response was assessed by analyzing the cellular proliferation of the splenocytes stimulated in vitro by a mitogen or rCFP32. ResultsThe ACE-treated mice showed a significant immunosuppression of the specific humoral response with a restorative effect of curcumin when administered with ACE. Similarly, ACE significantly decreased the level of splenocyte proliferation after either a non specific or a specific activation. Curcumin partially restores the antigen specific cellular immune response. Moreover, when administered alone, curcumin significantly inhibits the proliferative responses to the mitogen confirming its anti-mitogenic effect. Histological analysis showed alteration of spleens of mice exposed to ACE. SignificanceAltogether, our data indicated that ACE could potentially be harmful to the immune system.

Oral Administration of a Seed-based Bivalent Rotavirus Vaccine Containing VP6 and NSP4 Induces Specific Immune Responses in Mice.

Rotavirus is the leading cause of severe diarrheal disease among newborns. Plant-based rotavirus vaccines have been developed in recent years and have been proven to be effective in animal models. In the present study, we report a bivalent vaccine candidate expressing rotavirus subunits VP6 and NSP4 fused with the adjuvant subunit B of E. coli heat-labile enterotoxin (LTB) in maize seeds. The RT-PCR and Western blot results showed that VP6 and LTB-NSP4 antigens were expressed and accumulated in maize seeds. The expression levels were as high as 0.35 and 0.20% of the total soluble protein for VP6 and LTB-NSP4, respectively. Oral administration of transgenic maize seeds successfully stimulated systemic and mucosal responses, with high titers of serum IgG and mucosal IgA antibodies, even after long-term storage. This study is the first to use maize seeds as efficient generators for the development of a bivalent vaccine against rotavirus.

Lactococcus lactis carrying a DNA vaccine coding for the ESAT-6 antigen increases IL-17 cytokine secretion and boosts the BCG vaccine immune response.

A regimen utilizing Bacille Calmette-Guerin (BCG) and another vaccine system as a booster may represent a promising strategy for the development of an efficient tuberculosis vaccine for adults. In a previous work, we confirmed the ability of Lactococcus lactis fibronectin-binding protein A (FnBPA+) (pValac:ESAT-6), a live mucosal DNA vaccine, to produce a specific immune response in mice after oral immunization. In this study, we examined the immunogenicity of this strain as a booster for the BCG vaccine in mice. After immunization, cytokine and immunoglobulin profiles were measured. The BCG prime L. lactis FnBPA+ (pValac:ESAT-6) boost group was the most responsive group, with a significant increase in splenic pro-inflammatory cytokines IL-17, IFN-γ, IL-6 and TNF-α compared with the negative control. Based on the results obtained here, we demonstrated that L. lactis FnBPA+ (pValac:ESAT-6) was able to increase the BCG vaccine general immune response. This work is of great scientific and social importance because it represents the first step towards the development of a booster to the BCG vaccine using L. lactis as a DNA delivery system.

Multi-walled carbon nanotubes functionalized with recombinant Dengue virus 3 envelope proteins induce significant and specific immune responses in mice

BackgroundDengue is the most prevalent arthropod-borne viral disease in the world. In this article we present results on the development, characterization and immunogenic evaluation of an alternative vaccine candidate against Dengue.MethodsThe MWNT-DENV3E nanoconjugate was developed by covalent functionalization of carboxylated multi-walled carbon nanotubes (MWNT) with recombinant dengue envelope (DENV3E) proteins. The recombinant antigens were bound to the MWNT using a diimide-activated amidation process and the immunogen was characterized by TEM, AFM and Raman Spectroscopy. Furthermore, the immunogenicity of this vaccine candidate was evaluated in a murine model.ResultsImmunization with MWNT-DENV3E induced comparable IgG responses in relation to the immunization with non-conjugated proteins; however, the inoculation of the nanoconjugate into mice generated higher titers of neutralizing antibodies. Cell-mediated responses were also evaluated, and higher dengue-specific splenocyte proliferation was observed in cell cultures derived from mice immunized with MWNT-DENV3E when compared to animals immunized with the non-conjugated DENV3E.ConclusionsDespite the recent licensure of the CYD-TDV dengue vaccine in some countries, results from the vaccine’s phase III trial have cast doubts about its overall efficacy and global applicability. While questions about the effectiveness of the CYD-TDV vaccine still lingers, it is wise to keep at hand an array of vaccine candidates, including alternative non-classical approaches like the one presented here.

Porcine epidemic diarrhea virus virus-like particles produced in insect cells induce specific immune responses in mice.

Porcine epidemic diarrhea virus (PEDV), which causes 80–100% mortality in neonatal piglets, is one of the most devastating viral diseases affecting swine worldwide. To date, the lack of effective vaccines and drugs is the main problem preventing control of the global spread of PEDV. In this study, we produced PEDV virus-like particles (VLPs) composed of S, M, and E proteins with a baculovirus expression system and tested them via indirect immunofluorescence assay (IFA)and Western blot analysis. Electron microscopy showed that the morphological structure of the PEDV VLPs was similar to that of the protovirus. Microneutralization assays and ELISpot analysis demonstrated that PEDV VLPs induced highly specific antibody responses and Th2-mediated humoral immunity. As a result, the PEDV VLPs displayed excellent immunogenicity in mice. Therefore, a VLP-based vaccine has the potential to prevent PEDV infection.

Factors that Influence the Immunological Adjuvant Effect of Lactobacillus fermentum PC1 on Specific Immune Responses in Mice to Orally Administered Antigens.

This study examined the influences of the dosage of the adjuvant, the nature of the antigen and the host genetics on the capacity of L. fermentum PC1 (PC1) to function as an oral adjuvant. BALB/c and DBA/1 mice were vaccinated with either ovalbumin (OVA) or Salmonella Typhimurium on days 0 and 14, Mice were also dosed with the PC1 (108 CFU or 1011 CFU per dose per mouse) with the antigens (days 0 and 14) and alone (days −1 and 13). The higher PC1 dose elicited a greater specific serum IgG2a response than IgG1 for both antigens and mice strains, indicating a Th1-biased humoral immune response. The Th1 bias was also observed at the cellular level with greater specific IFN-γ levels than IL-4 and IL-10 with both antigen types and mouse strains. With the particulate antigen, the lower dose of PC1 elicited a Th1 bias at the cellular level, but a balanced Th1/Th2 response at the systemic humoral level. With the soluble antigen, a strong Th1-biased response occurred at the cellular level while the systemic humoral response was Th2-biased. In conclusion, PC1 at the higher dose was an excellent Th1 adjuvant, which was unaffected by the nature of the antigen or the host’s genetic background.

One-prime multi-boost strategy immunization with recombinant DNA, adenovirus, and MVA vector vaccines expressing HPV16 L1 induces potent, sustained, and specific immune response in mice

Human papillomavirus (HPV) is associated with various human diseases, including cancer, and developing vaccines is a cost-efficient strategy to prevent HPV-related disease. The major capsid protein L1, which an increasing number of studies have confirmed is typically expressed early in infection, is a promising antigen for such a vaccine, although the E6 and E7 proteins have been characterized more extensively. Thus, the L1 gene from HPV16 was inserted into a recombinant vector, AdHu5, and MVA viral vectors, and administered by prime-boost immunization. Virus-like particles were used as control antigens. Our results indicate that prime-boost immunization with heterologous vaccines induced robust and sustained cellular and humoral response specific to HPV16 L1. In particular, sera obtained from mice immunized with DNA + DNA + Ad + MVA had excellent antitumor activity in vivo. However, the data also confirm that virus-like particles can only elicit low levels cellular immunity and not be long-lasting, and are therefore unsuitable for treatment of existing HPV infections.

Recombinant CP40 from Corynebacterium pseudotuberculosis confers protection in mice after challenge with a virulent strain

BackgroundCaseous Lymphadenitis (CLA) is a contagious, infectious, chronic disease caused by Corynebacterium pseudotuberculosis, which affects mainly sheep and goats. The clinical prevalence of CLA in Brazil is 30%, resulting in decreased milk production, weight loss, and unusable meat and leather. Prophylaxis is based on vaccination; however, current vaccinations do not offer effective protection against the infection, which makes the development of a new vaccine essential to control this disease. Experimental approachHere, we developed a recombinant vaccine based on CP40 protein (rCP40) combined with an adjuvant (Freund's complete adjuvant or saponin) and evaluated its efficacy in a murine model of CLA. Female BALB/c mice were used in an immunization assay. Key resultsrCP40 induced high levels of IgG2a and IgG2b antibodies. After challenge with a virulent strain of C. pseudotuberculosis C57 (104CFU/mL), the levels of IgG2a and IgG2b were sustained, indicating a Th1 response. The groups immunized with rCP40 protein (GES and GEF groups) showed 100% protection and was statistically significant in the GES and GEF groups (p<0.037 and p<0.0952, respectively). ConclusionsThe results indicated the recombinant protein CP40 induced an specific immune response in mice that was able to afford protection after challenge, regardless the adjuvant used in the formulation.