Formulation of a recombinant HIV-1 polytope candidate vaccine with naloxone/alum mixture: induction of multi-cytokine responses with a higher regulatory mechanism

Investigation of Immunostimulatory Effects of IFN-γ Cytokine and CD40 Ligand Costimulatory Molecule for Development of HIV-1 Therapeutic Vaccine Candidate

The most crucial disadvantage of DNA-based vaccines is their low immunogenicity; therefore, finding an effectual adjuvant is essential for their development. Herein, immunostimulatory effects of IFNγ cytokine and a CD40 ligand (CD40L) costimulatory molecule are evaluated as combined with an antigen, and also linked to an antigen in mice. For this purpose, after preparation of the HIV-1 Nef, IFNγ, and CD40L DNA constructs, and also their recombinant protein in an Escherichia coli expression system, nine groups of female BALB/c mice are immunized with different regimens of DNA constructs. About 3 weeks and also 3 months after the last injection, humoral and cellular immune responses are assessed in mice sera and splenocytes. Additionally, mice splenocytes are exposed to single-cycle replicable (SCR) HIV-1 virions for evaluating their potency in the secretion of cytokines in vitro. The data indicate that the linkage of IFNγ and CD40L to Nef antigen can significantly induce the Th-1 pathway and activate cytotoxic T lymphocytes compared to other regimens. Moreover, groups receiving the IFNγ-Nef and CD40L-Nef fusion DNA constructs show higher secretion of IFNγ and TNF-α from virion-infected lymphocytes than other groups. Therefore, the IFNγ-Nef and CD40L-Nef fusion DNA constructs are suggested to be a potential option for development of an efficient HIV-1 vaccine.

Nanoadjuvants Produced by Advanced Nanochelating Technology in the Inactivated-Severe Acute Respiratory Syndrome Coronavirus-2 Vaccine Formulation: Preliminary Results on Cytokines and IgG Responses

Despite the great success of vaccines in various infectious diseases, most current vaccines are not effective enough, and on the contrary, clinically approved alum adjuvants cannot induce sufficient immune responses, including a potent cellular immune response to confer protection. In this study, we used Nanochelating Technology to develop novel nanoadjuvants to boost the potency of the alum-adjuvanted inactivated severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccine. BALB/c mice were immunized twice over 2 weeks with different doses of adjuvanted-vaccine formulations and immune responses were assessed. The analysis results of IFN-γ and IL-17 cytokines demonstrated the effectiveness of the nanoadjuvants produced by the Nanochelating Technology in shifting the alum-based vaccine toward a stronger Th1 pattern. In addition, these nanoadjuvants improved IL-2 cytokine response, which shows the efficacy of these novel formulations in inducing specific T lymphocyte proliferation. Using these nanoadjuvants increased IL-10 cytokine secretion that may be representative of a better immunoregulatory impact and may also potentially prevent immunopathology responses. Moreover, specific IgG titer analysis revealed the potency of these nanoadjuvants in improving humoral immune responses. The enzyme-linked immunosorbent assay of receptor-binding domain (RBD)-specific IgG response showed that the developed novel formulations induced strong IgG responses against this protein. This study shows that the nanostructures produced by the Advanced Nanochelating Technology have potent adjuvant effects on alum-based SARS-CoV-2 vaccines to not only compensate for alum weakness in inducing the cellular immune responses by smart regulation of the immune system but also significantly improve the humoral and cellular immune responses simultaneously.

Different Formulations of Inactivated SARS-CoV-2 Vaccine Candidates in Human Compatible Adjuvants: Potency Studies in Mice Showed Different Platforms of Immune Responses

Several inactivated SARS-CoV-2 vaccines have been approved for human use, but are not highly potent. In this study, different formulations of the inactivated SARS-CoV-2 virus were developed in Alum, Montanide 51VG, and Montanide ISA720VG adjuvants, followed by assessment of immune responses. The SARS-CoV-2 virus was inactivated with formalin and formulated in the adjuvants. BALB/c mice were immunized subcutaneously with 4 μg of vaccines on days 0 and 14; (IL-4) and (IFN-g), cytotoxic T lymphocyte (CTL) activity, and specific immunoglobulin G (IgG) titer and IgG1, IgG2a, and IgG2a/IgG1 ratio, and anti-receptor-binding domain (RBD) IgG response were assessed 2 weeks after the final immunization. Immunization with SARS-CoV-2-Montanide ISA51VG showed a significant increase in the IFN-γ cytokine versus SARS-CoV-2-Alum, SARS-CoV-2-Montanide ISA720VG, and control groups (p < 0.0033). Cytokine IL-4 response in SARS-CoV-2-Alum group showed a significant increase compared with SARS-CoV-2-Montanide ISA51VG, SARS-CoV-2-Montanide ISA720VG, and control groups (p < 0.0206). In addition, SARS-CoV-2-Montanide ISA51VG vaccine induced the highest IFN-γ/IL-4 cytokine ratio versus other groups (p < 0.0004). CTL activity in SARS-CoV-2-Montanide ISA51VG and SARS-CoV-2-Montanide ISA720VG groups showed a significant increase compared with SARS-CoV-2-Alum and control groups (p < 0.0075). Specific IgG titer in SARS-CoV-2-Montanide ISA51 VG and SARS-CoV-2-Montanide ISA720VG showed a significant increase compared with SARS-CoV-2-Alum and control groups (p < 0.0143). Results from specific IgG1and IgG2a in SARS-CoV-2-Alum, SARS-CoV-2-Montanide ISA51VG, and SARS-CoV-2-Montanide ISA720VG vaccine showed a significant increase compared with phosphate buffer saline (PBS) group (p < 0.0001), but SARS-CoV-2-Montanide ISA51VG and SARS-CoV-2-Montanide ISA 720VG groups showed the highest IgG2a/IgG1 ratio and a significant increase compared with SARS-CoV-2-Alum group (p < 0.0379). Moreover, inactivated SARS-CoV-2+Alum and SARS-CoV-2-Montanide ISA 720VG groups demonstrated a significant increase in anti-RBD IgG response versus the SARS-CoV-2-Montanide ISA51VG group. It seems that the type of vaccine formulation is a critical parameter, influencing the immunologic pattern and vaccine potency and human-compatible oil-based adjuvants were more potent than Alum adjuvant in the vaccine formulation.