Immunostimulatory effects of Hsp70 fragments and Hsp27 in design of novel HIV-1 vaccine formulations

BACKGROUND

Heat shock proteins (HSPs) as an adjuvant induce antigen-specific immunity through facilitating antigen presentation and stimulating T cells. In this study, the immunostimulatory properties of two major fragments of Hsp70 (N-Hsp70(aa 1-387) with ATPase property and C-Hsp70 (aa 508-641) with peptide-binding capacity) and the full length of Hsp27 as vaccine adjuvants were evaluated to boost HIV-1 Nef antigen-specific immunity in both in vitro and in vivo experiments.

METHODS

At first, the nanoparticles harbouring DNA fusion constructs (i.e. N-Hsp70-Nef, C-Hsp70-Nef and Hsp27-Nef) complexed with HIV Rev (34-50) cell-penetrating peptide were generated to deliver DNA into the cells. Then, the recombinant Nef, Hsp27-Nef, N-Hsp70-Nef and C-Hsp70-Nef proteins were generated in E.coli expression system. Next, the immunostimulatory properties of these fusion constructs were evaluated in both in vitro and in vivo studies. Finally, the secretion of main cytokines from single-cycle replicable (SCR) HIV-1 virion-exposed splenocytes was investigated.

RESULTS

Our data showed that the stable and non-toxic DNA/Rev nanoparticles could successfully deliver the genes of interest into the cells. Moreover, higher secretion of antibodies and cytokines was detected in mice receiving the Hsp-Nef constructs than in mice receiving Nef antigen. The C-Hsp70 was also superior for inducing Nef-specific Th1 and CTL immunity compared with N-Hsp70 and Hsp27. The T-cell activity was maintained in the SCR-exposed splenocytes, especially the splenocytes of mice receiving the C-Hsp70-Nef regimen.

CONCLUSION

Altogether, these findings demonstrate the significance of Hsps as enhancers of antigen-specific immunity. Notably, the C-Hsp70 region showed better adjuvant properties for inducing cellular immunity in the improvement of HIV-1 therapeutic vaccines.

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.

Impact of TRIM5α and TRIM22 Genes Expression on the Clinical Course of Coronavirus Disease 2019

OBJECTIVE

The innate immune response in humans involves a wide variety of factors, including the tripartite motif-containing 5α (TRIM5α) and 22 (TRIM22) as a cluster of genes on chromosome 11 that have exhibited antiviral activity in several viral infections. We analyzed the correlation of the expression of TRIM5α and TRIM22 with the severity of Coronavirus Disease 2019 (COVID-19) in blood samples of 330 patients, divided into two groups of severe and mild disease, versus the healthy individuals who never had contact with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2).

METHODS

The transcription level of TRIM5α and TRIM22 was determined by quantitative real-time polymerase chain reaction (qPCR). The laboratory values were collected from the patients' records.

RESULTS

The expression of both genes was significantly lower in the severe group containing the hospitalized patients than in both the mild group and the control group. However, in the mild group, TRIM22 expression was significantly higher (p <0.0001) than in the control group while TRIM5α expression was not significantly different between these two groups. We found a relationship between the cycle threshold (Ct) value of patients and the expression of the aforementioned genes.

CONCLUSION

The results of our study indicated that lower Ct values or higher RNA viral load might be associated with the downregulation of TRIM5α and TRIM22 and the severity of COVID-19. Additional studies are needed to confirm the results of this study.

Association between serum inflammatory parameters and the disease severity in COVID-19 patients

Objective

Most patients infected with the novel coronavirus (SARS‐CoV‐2), as the causative agent of COVID‐19 disease, show mild symptoms, but some of them develop severe illness. The purpose of this study was to analyze the blood markers of COVID‐19 patients and to investigate the correlation between serum inflammatory cytokines and the disease severity.

Methods

In this prospective cross‐sectional study, 50 patients with COVID‐19 and 20 patients without COVID‐19 were enrolled. According to ICU admission criteria, patients were divided into two groups of non‐severe and severe. Differences in the serum levels of C‐reactive protein (CRP), IL‐6, and TNF‐α, as well as erythrocyte sedimentation rate (ESR), lymphocytes (LYM) count, and neutrophils (NEU) count between the two groups were determined and analyzed.

Results

Out of the 50 patients with COVID‐19, 14 were diagnosed as severe cases. There was no significant difference between the two groups of COVID‐19 patients in terms of gender and age. Blood tests of COVID‐19 patients showed a significant decrease and increase in NEU and LYM counts, respectively. There were significant differences in the serum levels of IL‐6, TNF‐α, and CRP between the severe and non‐severe groups, which were higher in the severe group.

Also, there was a significant correlation between the disease severity and CRP with ESR (r = 0.79), CRP with IL‐6 (r = 0.74), LYM with NEU (r = −0.97), and ESR with TNF‐α (r = 0.7).

Conclusion

The findings of this study, as the first study in Iran, suggest that the levels of IL‐6, TNF‐α, ESR, and CRP could be used to predict the severity of COVID‐19 disease.