Publications by authors named "Hamidreza Hashemi"

Poorly immunogenic small molecules pose challenges for the production of clinically efficacious vaccines and antibodies. To address this, we generate an immunization platform derived from the immunogenic surface coat of the African trypanosome. Through sortase-based conjugation of the target molecules to the variant surface glycoprotein (VSG) of the trypanosome surface coat, we develop VSG-immunogen array by sortase tagging (VAST).

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The dense variant surface glycoprotein (VSG) coat of African trypanosomes represents the primary host-pathogen interface. Antigenic variation prevents clearing of the pathogen by employing a large repertoire of antigenically distinct VSG genes, thus neutralizing the host's antibody response. To explore the epitope space of VSGs, we generate anti-VSG nanobodies and combine high-resolution structural analysis of VSG-nanobody complexes with binding assays on living cells, revealing that these camelid antibodies bind deeply inside the coat.

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With an increasing number of patients with degenerative hepatic diseases, such as liver fibrosis, and a limited supply of donor organs, there is an unmet need for therapies that can repair or regenerate damaged liver tissue. Treatment with macrophages that are capable of phagocytosis and anti-inflammatory activities such as secretion of matrix metalloproteinases (MMPs) provide an attractive cellular therapy approach. Human induced pluripotent stem cells (iPSCs) are capable of efficiently generating a large-scale, homogenous population of human macrophages using fully defined feeder- and serum-free differentiation protocol.

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Suramin has been a primary early-stage treatment for African trypanosomiasis for nearly 100 yr. Recent studies revealed that trypanosome strains that express the variant surface glycoprotein (VSG) VSGsur possess heightened resistance to suramin. Here, we show that VSGsur binds tightly to suramin but other VSGs do not.

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Single nucleotide changes were introduced into the non-structural (NS) coding sequence of the H-1 parvovirus (PV) infectious molecular clone and the corresponding virus stocks produced, thereby generating H1-PM-I, H1-PM-II, H1-PM-III, and H1-DM. The effects of the mutations on viral fitness were analyzed. Because of the overlapping sequences of NS1 and NS2, the mutations affected either NS2 (H1-PM-II, -III) or both NS1 and NS2 proteins (H1-PM-I, H1-DM).

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We report here the development of multivalent T7 bacteriophage nanoparticles displaying an immunodominant H-2k(d)-restricted CTL epitope derived from the rat HER2/neu oncoprotein. The immunotherapeutic potential of the chimeric T7 nanoparticles as anti-cancer vaccine was investigated in BALB/c mice in an implantable breast tumor model. The results showed that T7 phage nanoparticles confer a high immunogenicity to the HER-2-derived minimal CTL epitope, as shown by inducing robust CTL responses.

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Considering the emergence of highly pathogenic influenza viruses and threat of worldwide pandemics, there is an urgent need to develop broadly-protective influenza vaccines. In this study, we demonstrate the potential of T7 bacteriophage-based nanoparticles with genetically fused ectodomain of influenza A virus M2 protein (T7-M2e) as a candidate universal flu vaccine. Immunization of mice with non-adjuvanted T7-M2e elicited M2e-specific serum antibody responses that were similar in magnitude to those elicited by M2e peptide administered in Freund's adjuvant.

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DNA vaccines have emerged as an attractive approach to induce CTL responses against cancer and infectious agents in recent years. Although CTL induction by DNA vaccination would be a valuable strategy for controlling viral infections, increasing the potency of DNA vaccines is mandatory before DNA vaccines can make it to the clinic. In this study, we developed and characterized a new and safe adjuvanted delivery system for DNA vaccination using cationic influenza virosomes (CIV).

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Influenza virosome is one of the commercially available vaccines that have been used for a number of years. Like other influenza vaccines, the efficacy of the virosomal vaccine is significantly compromised when circulating viruses do not have a good match with vaccine strains due to antigenic drift or less frequent emergence of a pandemic virus. A major advantage of virosome over other influenza vaccine platforms is its intrinsic adjuvant activity and potential carrier capability which have been exploited in this study to broaden vaccine protectivity by incorporating a conserved component of influenza virus in seasonal vaccine formulation.

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In a previous study, the authors have shown that herpes simplex virus type 1 (HSV-1) glycoprotein B DNA vaccine but not live vaccine (non-virulent KOS strain) failed to induce protective immunity against acute HSV-1 challenge in morphine-dependent mice. The present study reports the effect of morphine withdrawal on protective immunity induced by live HSV-1 immunization. BALB/c mice were vaccinated with KOS strain as a live vaccine.

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Background: Studies on efficacy of various vaccines that prevent or reduce the primary and recurrent HSV-1 infection have demonstrated the importance of cellular immunity for protection against the infection. We previously used DNA vaccination to induce cellular immunity against HSV-1 infection in mice.

Objective: The aim of our study was to evaluate the effect of LIGHT; a member of TNF super family, on the kinetic of CTL response induced by HSV-1 glycoprotein B based DNA vaccine.

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Influenza virus infections cause yearly epidemics and are a major cause of lower respiratory tract illnesses in humans worldwide. Influenza virus has long been recognized to be associated with higher morbidity and mortality in diabetic patients. Vaccination is an effective tool to prevent influenza virus infection in this group of patients.

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Although the role of various cytokines on stimulating the immune responses is characterized well, the importance of LIGHT, a member of TNF superfamily, is less clear. In the current study, we administrated LIGHT expression plasmid as an adjuvant to HSV-1 gB DNA vaccine. HSV-1 gB DNA can elicit vigorous humoral and cell mediated immunity in BALB/c mice.

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Phage display is based on expressing peptides as a fusion to one of the phage coat proteins. To date, many vaccine researches have been conducted to display immunogenic peptides or mimotopes of various pathogens and tumors on the surface of filamentous bacteriophages. In recent years as a new approach to application of phages, recombinant bacteriophage lambda particles were used as DNA delivery vehicles to mammalian cells.

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