Expression and identification of immunological activities of the HIV-gp120N-human interferon gamma fusion protein

In silico designing of novel epitope-based peptide vaccines against HIV-1

The HIV-1 virus has been regarded as a catastrophe for human well-being. The global incidence of HIV-1-infected individuals is increasing. Hence, development of effective immunostimulatory molecules has recently attracted an increasing attention in the field of vaccine design against HIV-1 infection. In this study, we explored the impacts of CD40L and IFN-γ as immunostimulatory adjuvants for our candidate HIV-1 Nef vaccine in human and mouse using immunoinformatics analyses. Overall, 18 IFN-γ-based vaccine constructs (9 constructs in human and 9 constructs in mouse), and 18 CD40L-based vaccine constructs (9 constructs in human and 9 constructs in mouse) were designed. To find immunogenic epitopes, important characteristics of each component (e.g., MHC-I and MHC-II binding, and peptide-MHC-I/MHC-II molecular docking) were determined. Then, the selected epitopes were applied to create multiepitope constructs. Finally, the physicochemical properties, linear and discontinuous B cell epitopes, and molecular interaction between the 3D structure of each construct and CD40, IFN-γ receptor or toll-like receptors (TLRs) were predicted. Our data showed that the full-length CD40L and IFN-γ linked to the N-terminal region of Nef were capable of inducing more effective immune response than multiepitope vaccine constructs. Moreover, molecular docking of the non-allergenic full-length- and epitope-based CD40L and IFN-γ constructs to their cognate receptors, CD40 and IFN-γ receptors, and TLRs 4 and 5 in mouse were more potent than in human. Generally, these findings suggest that the full forms of these adjuvants could be more efficient for improvement of HIV-1 Nef vaccine candidate compared to the designed multiepitope-based constructs.

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.

A DNA vaccine (EG95-PT1/2/3-IL2) encoding multi-epitope antigen and IL-2 provokes efficient and long-term immunity to echinococcosis

Echinococcosis is a highly prevalent global zoonosis, and vaccines are required. The commercial vaccine based on a protein-based subunit (EG95), however, is limited by its insufficient cellular immunity, a short protection period, and limited prevention against novel mutant strains. Herein, we applied bioinformatics to develop a DNA vaccine (pEG95-IL2) expressing both multi-epitope-based antigens (EG95-PT1/2/3) and an IL-2 adjuvant to regulate T cell differentiation and memory cell response. EG95-PT1/2/3 was screened with hierarchical structure prediction from the epitope conformation of B cells with high confidence across various species to guarantee immunogenicity. Importantly, cationic arginine-rich lipid nanoparticles (RNP) were utilized as a delivery vehicle to form lipoplexes that had a transfection efficiency of nearly two orders of magnitude greater than that of commercial reagents (Lipofectamine 2000 and polyethyleneimine) with both immune and nonimmune cells (DC2.4 and L929 cells, respectively). RNP/pEG95-IL2 lipoplexes displayed a robust and long-term antigen expression, as well as adjuvant effects during the immunization. Consequently, intramuscular injection of RNP/pEG95-IL2 elicited similar humoral immune responses and significantly greater cellular responses in mice when compared with those of the commercial vaccine. In addition, the inoculation protocol of RNP/pEG95-IL2 with sequential booster further strengthens cellular immunity in comparison with the homologous booster. Those findings provide a promising strategy for improving plasmid vaccine efficacy.

Modulatory effects of the CCR5 antagonist maraviroc on microglial pro-inflammatory activation elicited by gp120

Despite important clinical benefits of the highly active antiretroviral therapy, neurological disorders affect approximately 50% of AIDS patients. In the brain, infected microglia release pro-inflammatory mediators as well as human immunodeficiency virus type 1 (HIV-1) proteins, like the envelope protein gp120, that sustain inflammation and mediate neuronal damage. Gp120 allows the virus entry in the host cells via binding to the CD4 receptor together with a specific co-receptor (CCR5/CXCR4). The antiretroviral drug maraviroc is a CCR5 receptor antagonist, approved for the treatment of HIV-experienced patients. By interfering with a chemokine receptor, highly expressed in microglia, maraviroc has the potential to modulate their activation during HIV-1 infection. To test this hypothesis, primary cultures of rat cortical microglia were activated by gp120. Gp120(CN54) , a protein derived by macrophage (M)-tropic viruses, showed strong pro-inflammatory action, thus it was used to test the effects of maraviroc. The latter displayed opposite effects, depending on whether or not interferon-γ (IFNγ) was also present in the system. IFNγ significantly enhanced gp120 proinflammatory activity, possibly via up-regulation of CCR5 receptor expression. In this experimental paradigm, maraviroc significantly increased microglial activation, thus suggesting that its chronic use can exacerbate neuronal pathology, especially in HIV-experienced patients with higher cerebral IFNγ levels.