Adjuvants For Immune Responses Research Articles

Listeriolysin O immunogenetic adjuvant enhanced potency of hepatitis C virus NS3 DNA vaccine.

Hepatitis C virus (HCV) is a major health problem all over the world. Among HCV proteins, nonstructural protein 3 (NS3) is one of the most promising target for anti-HCV therapy and a candidate for vaccine design. DNA vaccine is an efficient approach to stimulate antigen-specific immunity but the main problem with that is less immunogenic efficiency in comparison with traditional vaccines. Several approaches have been applied to enhance the immunogenicity of DNA. Recently, bacteria-derived substances are considered as one of the most attractive adjuvants for vaccines, which among them, Listeriolysin O (LLO) of Listeria monocytogenes is a toxin with an extremely immunogenic feature. We investigated detoxified form of LLO gene as genetic adjuvant to modulate NS3 DNA vaccine potency. Immunogenic truncated NS3 gene sequence of HCV (1095-1380aa) and detoxified LLO gene region (5-441aa) were amplified by PCR and cloned into the pcDNA3.1 plasmid separately. The expression of recombinant proteins (pc-NS3, pLLO) was confirmed in HEK293T cell line by western blotting. BALB/c mice models received three doses of different formula of plasmids in two-week intervals and two weeks after the final immunization, the immune responses were evaluated by specific total antibody level, lymphocyte proliferation, cytotoxicity, and cytokine levels assays. To evaluate in vivo cytotoxic activity, tumor challenge was performed. The recombinant plasmids were successfully expressed in mammalian cell line, and coadministration of pc-NS3 with pLLO induced the highest titer of total IgG against NS3 antigen compared with other controls. Determination of IgG subclasses confirmed the efficient increase in mixed responses with Th1 dominancy. Furthermore, significant levels of cytokines (p < .05) and lymphocyte proliferation responses (p < .05) indicated the superiority of this regimen. The findings may have important implication for LLO gene application as genetic adjuvant in immune response against HCV.

Evaluation of adjuvant activity of fractions derived from Agaricus blazei, when in association with the recombinant LiHyp1 protein, to protect against visceral leishmaniasis

The development of effective prophylactic strategies to prevent leishmaniasis has become a high priority. No less important than the choice of an antigen, the association of an appropriate adjuvant is necessary to achieve a successful vaccination, as the majority of the tested antigens contain limited immunogenic properties, and need to be supplemented with immune response adjuvants in order to boost their immunogenicity. However, few effective adjuvants that can be used against leishmaniasis exist on the market today; therefore, it is possible to speculate that the research aiming to identify new adjuvants could be considered relevant. Recently, Agaricus blazei extracts have proved to be useful in enhancing the immune response to DNA vaccines against some diseases. This was based on the Th1 adjuvant activity of the polysaccharide-rich fractions from this mushroom. In this context, the present study evaluated purified fractions derived from Agaricus blazei as Th1 adjuvants through in vitro assays of their immune stimulation of spleen cells derived from naive BALB/c mice. Two of the tested six fractions (namely F2 and F4) were characterized as polysaccharide-rich fractions, and were able to induce high levels of IFN-γ, and low levels of IL-4 and IL-10 in the spleen cells. The efficacy of adjuvant action against L. infantum was evaluated in BALB/c mice, with these fractions being administered together with a recombinant antigen, LiHyp1, which was previously evaluated as a vaccine candidate, associated with saponin, against visceral leishmaniasis (VL). The associations between LiHyp1/F2 and LiHyp1/F4 were able to induce an in vivo Th1 response, which was primed by high levels of IFN-γ, IL-12, and GM-CSF, by low levels of IL-4 and IL-10; as well as by a predominance of IgG2a antibodies in the vaccinated animals. After infection, the immune profile was maintained, and the vaccines proved to be effective against L. infantum. The immune stimulatory effects in the BALB/c mice proved to be similar when comparing the F2 and F4 fractions with a known Th1 adjuvant (saponin), though animals vaccinated with saponin did present a slight to moderate inflammatory edema on their hind footpads. In conclusion, the F2 and F4 fractions appear to induce a Th1-type immune response and, in this context, they could be evaluated in association with other protective antigens against Leishmania, as well as in other disease models.

The role of Montanide ISA 70 as an adjuvant in immune responses against Leishmania major induced by thiol-specific antioxidant-based protein vaccine.

Leishmaniasis is a parasitic disease caused by several species of the genus Leishmania. Montanide ISA 70 is an adjuvant composed of a natural metabolizable oil and a very refined emulsifier from the manide monooleate family. The TSA (thiol-specific antioxidant) is a important antigen of Leishmania major. The purpose of this work was protein-vaccine efficacy as an protection and excellent candidate in the presence Montanide. The expression of recombinant protein was confirmed with SDS (sodium dodecyl sulfate) page and Western bloting. 48 BALB/c mice were divided into four groups (TSA/Freund,TSA/Alum+BCG, TSA/Montanide and PBS groups) and immunized with 20μg of vaccine subcutaneously three times intervals on days 0, 14 and 28. The mice were challenged with parasite 21days after final immunization. The lymphocyte proliferation was evaluated with Brdu method. Cytokines and also total antibody and subclasses were evaluated with ELISA method. The vaccine formulated with the recombinant TSA protein with Montanide induced lymphocytes proliferation cytokines and total antibody and subclasses as compared with the control group.

Lipid Nanoparticles as Vehicles for Macromolecules: Nucleic Acids and Peptides

Traditional drug delivery systems are not efficient for peptide, protein and nucleic acid (plasmid DNA, oligonucleotides or short interfering RNA) delivery, thereby LNP have been exploited as potential delivery and targeting systems of these molecules. Since their discovery in the early 90's several research groups have focused their efforts on the improvement of this kind of nanocarriers in terms of effectiveness and safety. This review features the recent and most relevant patents related to these topics, with particular attention to targeting and protection from environmental agents. Moreover, in the case of nucleic acids strategies to improve transfection mediated by lipid nanoparticles (entrance to the cells, intracellular distribution or going through nuclear envelope) will be assessed. Regarding peptides and proteins, enhancement of encapsulation efficiency and absorption through mucoses are the main studied drawbacks. Finally, this work also includes a summary of the existing patents about the use of LNP as immune response adjuvants by using either plasmid DNA or proteins.

Vaccine candidates in STD.

Sexually transmitted diseases (STDs) are caused by organisms that infect the mucosal surfaces of the genitourinary tract. In spite of its public health importance, current STD vaccine research lags behind work against pathogens that target another mucosal region, the respiratory tract. In the latter case, live-attenuated viral vaccines, killed whole-cell bacterial vaccines, subunit/protein bacterial vaccines, and bacterial polysaccharide vaccines have been enormously successful. To move STD vaccine research forward, complex issues must be resolved. Those include selection of an appropriate antigen (e.g. scientific feasibility and intellectual property rights), the manufacture of the vaccine (e.g. delivery systems, formulation processes, and production steps), and the appropriate public health approach (e.g. medical indications and marketing aspects). Particular scientific problems have delayed STD vaccine development, like incomplete attenuation (human herpes simplex virus type 2), accentuated immunopathology (Chlamydia trachomatis), poor immunogenicity (Treponema pallidum), and broad antigenic heterogeneity (Neisseria gonorrhoeae). Nevertheless, efforts continue with the use of protein antigens: for example, the haemolysin toxoid of Haemophilus ducreyi; the major outer membrane protein(s) of N. gonorrhoeae and C. trachomatis; the glycoprotein D of human herpes simplex virus type 2; and the proteins E6 and E7 of human papilloma virus. It may be predicted that eventual STD vaccines (administered either for prophylaxis or for therapy) will use approaches that include (1) live-attenuated viruses, (2) subunit proteins or inactivated whole organisms given with mucosal adjuvants or with cellular immune response adjuvants, and (3) DNA plasmids expressing the vaccine antigen.

Vaccine candidates in STD.

Sexually transmitted diseases (STDs) are caused by organisms that infect the mucosal surfaces of the genitourinary tract. In spite of its public health importance, particular scientific problems have delayed the development of an STD vaccine, such as incomplete attenuation (human herpes simplex virus type 2), accentuated immunopathology (Chlamydia trachomatis), poor immunogenicity (Treponema pallidum), and broad antigenic heterogeneity (Neisseria gonorrhoeae). Nevertheless, efforts continue with the use of protein antigens: for example, the haemolysin toxoid of Haemophilus ducreyi; the major outer membrane protein(s) of N. gonorrhoeae and C. trachomatis; the glycoprotein D of human herpes simplex virus type 2; and the proteins E6 and E7 of the human papillomavirus. It could be predicted that eventual STD vaccines (administered either for prophylaxis or for therapy) will use approaches that will include (1) live-attenuated viruses, (2) subunit proteins or inactivated whole organisms given with mucosal adjuvants or with cellular immune response adjuvants, or (3) DNA plasmids expressing the vaccine antigen.