Asghar Abdoli

Autophagy induction regulates influenza virus replication in a time-dependent manner

Purpose. Autophagy plays a key role in host defence responses against microbial infections by promoting degradation of pathogens and participating in acquired immunity. The interaction between autophagy and viruses is complex, and this pathway is hijacked by several viruses. Influenza virus (IV) interferes with autophagy through its replication and increases the accumulation of autophagosomes by blocking lysosome fusion. Thus, autophagy could be an effective area for antiviral research. Methodology. In this study, we evaluated the effect of autophagy on IV replication. Two cell lines were transfected with Beclin‐1 expression plasmid before (prophylactic approach) and after (therapeutic approach) IV inoculation. Results/Key findings. Beclin‐1 overexpression in the cells infected by virus induced autophagy to 26%. The log10haemagglutinin titre and TCID50 (tissue culture infective dose giving 50% infection) of replicating virus were measured at 24 and 48 h post‐infection. In the prophylactic approach, the virus titre was enhanced significantly at 24 h post‐infection (P≤0.01), but it was not significantly different from the control at 48 h post‐infection. In contrast, the therapeutic approach of autophagy induction inhibited the virus replication at 24 and 48 h post‐infection. Additionally, we showed that inhibition of autophagy using 3‐methyladenine reduced viral replication. Conclusion. This study revealed that the virus (H1N1) titre was controlled in a time‐dependent manner following autophagy induction in host cells. Manipulation of autophagy during the IV life cycle can be targeted both for antiviral aims and for increasing viral yield for virus production.

Autophagy induction reduces telomerase activity in HeLa cells.

Autophagy is a cellular homeostatic process whereby damaged proteins and organelles are encapsulated into double membrane vesicles, called autophagosomes, for lysosomal digestion. Beclin1 plays a key role in the initial steps of autophagosome formation. In this study, we evaluated the effect of Beclin 1 overexpression in induction of autophagy and the relationship between autophagy induction and telomerase activity in HeLa cells. We found that overexpression of Beclin 1 in HeLa cells leads to autophagosome formation as shown by intracellular autophagosomal marker LC3-II staining. Expression of Beclin1 reduced telomerase activity for about 100 fold compared with the control while it did not affect TERT expression level. The results of cell cycle analysis indicated that the cell cycle and proliferation progressed normally up to 48h post-transfection. Understanding the role of autophagy induction and telomerase in the pathophysiology of aging and human cancer reveal new strategies that hold much promise for intervention and therapeutic uses.

Comparison between MDCK and MDCK-SIAT1 cell lines as preferred host for cell culture-based influenza vaccine production

ObjectivesTo evaluate MDCK and MDCK-SIAT1 cell lines for their ability to produce the yield of influenza virus in different Multiplicities of Infection.ResultsYields obtained for influenza virus H1N1 grown in MDCK-SIAT1 cell was almost the same as MDCK; however, H3N2 virus grown in MDCK-SIAT1 had lower viral titers in comparison with MDCK cells. The optimized MOIs to infect the cells on plates and microcarrier were selected 0.01 and 0.1 for H1N1 and 0.001 and 0.01 for H3N2, respectively.ConclusionsMDCK-SIAT1 cells may be considered as an alternative mean to manufacture cell-based flu vaccine, especially for the human strains (H1N1), due to its antigenic stability and high titer of influenza virus production.

Influence of Brucella abortus lipopolysaccharide as an adjuvant on the immunogenicity of HPV-16 L1VLP vaccine in mice

Brucella abortus lipopolysaccharide (LPS) has less toxicity and no pyrogenic properties in comparison with other bacterial LPS. It is a toll-like receptor 4 agonist and has been shown to have the potential use as a vaccine adjuvant. In this study, the immunostimulatory properties of LPS from smooth and rough strains of B. abortus (S19 and RB51) as adjuvants were investigated for the human papillomavirus type 16 (HPV16) L1 virus-like particles (L1VLPs) vaccines. C57BL/6 mice were immunized subcutaneously three times either with HPV-16 L1VLPs alone, or in combination with smooth LPS (S-LPS), rough LPS (R-LPS), aluminum hydroxide or a mixture of them as adjuvant. The humoral immunity was evaluated by measuring the specific and total IgG levels, and also the T-cell immune response of mice was evaluated by measuring different cytokines such as IFN-γ, TNF-α, IL-4, IL-10 and IL-17. Results showed that serum anti-HPV16 L1VLP IgG antibody titers was significantly higher in mice immunized with a combination of VLPs and R-LPS or S-LPS compared with other immunized groups. Co-administration of HPV-16 L1VLPs with R-LPS elicited the highest levels of splenocytes cytokines (IFN-γ, IL-4, IL-17 and TNF-α) and also effectively induced improvement of a Th1-type cytokine response characterized with a high ratio of IFN-γ/IL-10. The data indicate that B. abortus LPS particularly RB51-LPS enhances the immune responses to HPV-16 L1VLPs and suggests its potential as an adjuvant for the development of a potent prophylactic HPV vaccine and other candidate vaccines.

An effective DNA priming-protein boosting approach for the cervical cancer vaccination.

Considerable advances have been made in developing human papillomaviruses (HPV) prophylactic vaccines based on L1 virus-like particles (VLPs). However, there are limitations in the availability of these vaccines in developing countries, where most cases of cervical cancer occur. In the current study, the prime-boost immunization strategies were studied using a DNA vaccine carrying HPV-16 L1 gene (pcDNA/L1) and insect cell baculovirus-derived HPV-16 L1 VLP. The humoral immunity was evaluated by measuring the specific IgG levels, and the T-cell immune response was assessed by measuring different cytokines such as IFN-γ, TNF-α and IL-10. Results showed that although immunization with pcDNA/L1 alone could induce strong cellular immune responses, higher immunogenicity especially antibody response was achieved in pcDNA/L1 priming-VLP boosting regimen. Therefore, we suggest that prime-boost regimen can be considered as an efficient prophylactic and therapeutic vaccine.

An H1-H3 chimeric influenza virosome confers complete protection against lethal challenge with PR8 (H1N1) and X47 (H3N2) viruses in mice

Annual health threats and economic damages caused by influenza virus are still a main concern of the World Health Organization and other health departments all over the world. An influenza virosome is a highly efficient immunomodulating carrier mimicking the natural antigen presentation pathway and has shown an excellent tolerability profile due to its biocompatibility and purity. The major purpose of this study was to construct a new chimeric virosome influenza vaccine containing hemagglutinin (HA) and neuraminidase (NA) proteins derived from the A/PR/8/1934 (H1N1) (PR8) and A/X/47 (H3N2) (X47) viruses, and to evaluate its efficacy as a vaccine candidate in mice. A single intramuscular vaccination with the chimeric virosomes provided complete protection against lethal challenge with the PR8 and X47 viruses. The chimeric virosomes induced high IgG antibody responses as well as hemagglutination inhibition (HAI) titers. HAI titers following the chimeric virosome vaccination were at the same level as the whole inactivated influenza vaccine. Mice immunized with the chimeric virosomes displayed considerably less weight loss and exhibited significantly reduced viral load in their lungs compared with the controls. The chimeric virosomes can be used as an innovative vaccine formulation to confer protection against a broad range of influenza viruses.

Autophagy: The multi-purpose bridge in viral infections and host cells

Autophagy signaling pathway is involved in cellular homeostasis, developmental processes, cellular stress responses, and immune pathways. The aim of this review is to summarize the relationship between autophagy and viruses. It is not possible to be fully comprehensive, or to provide a complete “overview of all viruses”. In this review, we will focus on the interaction of autophagy and viruses and survey how human viruses exploit multiple steps in the autophagy pathway to help viral propagation and escape immune response. We discuss the role that macroautophagy plays in cells infected with hepatitis C virus, hepatitis B virus, rotavirus gastroenteritis, immune cells infected with human immunodeficiency virus, and viral respiratory tract infections both influenza virus and coronavirus.

The effects of CpG-ODNs and Chitosan adjuvants on the elicitation of immune responses induced by the HIV-1-Tat-based candidate vaccines in mice

&NA; HIV1‐Tat‐based vaccines could elicit broad, durable and neutralizing immune responses and are considered as potential AIDS vaccines. The present study aims to formulate CpG‐ODNs adjuvant and Chitosan with Tat protein to enhance the immunogenicity of HIV‐1‐Tat‐based candidate vaccines and to investigate their efficacies in mice. To this end, we added CpG‐ODNs, Chitosan and Alum as adjuvants to the Tat‐based candidate vaccine formulations. Then, we compared frequency and magnitude of both humoral and cellular immune responses from mice immunized with the adjuvant‐formulated Tat candidate vaccines against those obtained from mice immunized with recombinant Tat protein alone. Mice were subcutaneously immunized three times at 2‐week intervals with the candidate vaccines. Measurements of anti‐Tat immune responses showed that all vaccinated groups had a good immunity compared to the control groups and developed high levels of both humoral and cellular responses. However, immunized mice with CpG‐ODNs, and Chitosan‐adjuvanted Tat vaccines elicited stronger T‐cell responses (both humoral and cellular immunity) compared to the others. These data suggest that co‐administration of recombinant Tat protein with CpG‐ODNs and Chitosan may serve as a potential formulation for enhancing of the Tat vaccine‐induced immunity and might have effects on shaping Th polarization induced by HIV1‐Tat protein vaccines.

Conjugated anionic PEG-citrate G2 dendrimer with multi-epitopic HIV-1 vaccine candidate enhance the cellular immune responses in mice

Abstract Multi-epitope vaccines might cause immunity against multiple antigenic targets. Four immunodominant epitopes of HIV-1 genome were used to construct a polytope vaccine, formulated by dendrimer. Two regimens of polytopes mixture with dendrimer were utilized to immunize BALB/c mice. Adjuvants were also used to boost immune responses. The conjugated polytope could arouse significant cellular immune responses (P < 0.05) and Th1 response showed higher intensity compared to Th2 (P < 0.05). Our study depicted that conjugated dendrimer with multi-epitopic rHIVtop4 would efficiently induce cell-mediated immune responses and might be considered as promising delivery system for vaccines formulation.

Suppressive Effects of Chronic Stress on Influenza Virus Protection after Vaccination with Plasmid DNA-Encoded Nucleoprotein.

Background: Influenza is a highly infectious and acute respiratory disease caused by an infection of the host respiratory tract mucosa by the influenza virus. The use of DNA vaccines that express conserved genes such as nucleoprotein (NP) represents a new method of vaccination against influenza. In this study, the effect of chronic stress on the efficiency of this type of vaccine has been evaluated in a mouse model. Methods: The NP DNA vaccine was administered intradermally 3 times on days 0, 3 and 6 to stressed and nonstressed male BALB/c mice. Two weeks after the last immunization, half of these mice were challenged with A/Puerto Rico/8/34 (PR8) influenza virus and were weighed for 12 days, and their mortality rate was assessed during this period. The cellular immune response of the other half of the mice was evaluated by cytotoxicity assay. Results: The results indicate a significant reduction in the cytotoxic T-lymphocyte response of stressed mice in comparison with unstressed mice. Also, the percentage of weight loss and mortality after the challenge in stressed mice was significantly increased compared to the other group. Conclusion: These results indicate that the NP DNA vaccine is not able to induce any effective cytotoxic T-lymphocyte response against influenza virus in stressed mice and cannot induce protective immunity against influenza infection in this group of mice.