Nanocurcumin as an adjuvant in killed Toxoplasma gondii vaccine formulation: An experience in BALB/c mice.

Toxoplasma gondii (T. gondii) remains as one of the controversial infections in the world. T. gondii is an important obligate intracellular protozoan parasite in the immune-deficient patients and pregnant women, sometimes leading to death and abortion, respectively. Herein, the adjuvant activity of nanocurcumin was assessed in the T. gondii killed vaccine model in BALB/c mice. In this study, 144 BALB/c mice were included in 8 groups and administered with different regimens of the vaccine; vac+30, 20 mg/kg of curcumin and nanocurcumin, vac + Freund's adjuvant, killed vac, vac + Alum adjuvant, and PBS via the subcutaneous route of immunization for three times with two-week intervals. Two weeks after the last immunization, the splenocytes' culture supernatant was evaluated for IL-4, IFN-γ, IL-2 and TNF-α cytokines and IFN-γ/IL-4, IFN-γ/TNF-α, and IL-2/IL-4 cytokine ratios using commercial ELISA kits. Specific total IgG antibodies, IgG1, and IgG2a were assessed with an optimized ELISA. Then the survival rate was determined 10 days after the experimental challenge. The results showed that the vaccine formulation in nanocurcumin at 20 mg/kg significantly increases IFN-γ cytokine and IFN-γ/IL4, IFN-γ/TNFα, and IL-2/IL4 ratios versus the vaccine formulated in curcumin, killed vaccine, and PBS group. In addition, specific total IgG antibody response showed that the vaccine formulated in nanocurcumin was more potent than that formulated in curcumin in the induction of humoral immune responses. Furthermore, results from the experimental challenge showed that nanocurcumin at a dose of 20 mg/kg could promote the life span of mice approximately by 12% versus the killed vaccine group. The present study showed that nanocurcumin in the vaccine formulation not only is more bioactive than curcumin in the modulation of cellular and humoral immune responses, but also provides more protectivity rate in the vaccinated mice on the killed T. gondii vaccine model. It seems that nanocurcumin can be used as an immunomodulator in vaccine formulation or as part of a complex adjuvant.

A cyclic peptide reproducing the α1 helix of VEGF-B binds to VEGFR-1 and VEGFR-2 and inhibits angiogenesis and tumor growth.

Vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) are pivotal regulators of angiogenesis. The VEGF-VEGFR system is therefore an important target of anti-angiogenesis therapy. Based on the X-ray structure of VEGF-B/VEGFR-1 D2, we designed a cyclic peptide (known as VGB1) reproducing the α1 helix and its adjacent region to interfere with signaling through VEGFR-1. Unexpectedly, VGB1 bound VEGFR-2 in addition to VEGFR-1, leading to inhibition of VEGF-stimulated proliferation of human umbilical vein endothelial cells and 4T1 murine mammary carcinoma cells, which express VGEFR-1 and VEGFR-2, and U87 glioblastoma cells that mostly express VEGFR-2. VGB1 inhibited different aspects of angiogenesis, including proliferation, migration and tube formation of endothelial cells stimulated by VEGF-A through suppression of extracellular signal-regulated kinase 1/2 and AKT (Protein Kinase B) phosphorylation. In a murine 4T1 mammary carcinoma model, VGB1 caused regression of tumors without causing weight loss in association with impaired cell proliferation (decreased Ki67 expression) and angiogenesis (decreased CD31 and CD34 expression), and apoptosis induction (increased TUNEL staining and p53 expression, and decreased Bcl-2 expression). According to far-UV circular dichroism (CD) and molecular dynamic simulation data, VGB1 can adopt a helical structure. These results, for the first time, demonstrate that α1 helix region of VEGF-B recognizes both VEGFR-1 and VEGFR-2.

A serologic study on Toxoplasma gondii infection in slaughtered sheep and goats in Qazvin Province, Iran.

BACKGROUND: Toxoplasma gondii is a common protozoan parasite among all mammals, in particular small ruminants, worldwide. Traditional husbandry can be a major risk factor for infection of sheep and goats with this parasite. OBJECTIVES: The present study aimed to determine the current status of the prevalence for T. gondii in livestock of Qazvin Province. METHODS: In this cross-sectional study, the sera of 455 sheep and 375 goats were examined to detect anti-Toxoplasma IgG antibodies by using in-house indirect ELISA. RESULTS: Overall, 33.62% (153/455) of sheep and 36.41% (130/375) of goats were positive for anti-Toxoplasma IgG antibodies with no statistically significant difference. The prevalence rate of T. gondii among the sheep of Qazvin County was significantly higher than in Abyek and Abhar counties (p < 0.001). CONCLUSIONS: The results of the present study indicate that the prevalence of T. gondii in sheep and goats of the study area is high. Therefore, the meat of the animals reared in this area can be a potential source of human infections by this parasite.

Synergistic effect of rSAG1 and rGRA2 antigens formulated in PLGA microspheres in eliciting immune protection against Toxoplasama gondii.

There is still no human vaccine against Toxoplasma gondii (T. gondii), as one of the most successful parasites. In present study, we designed a subunit vaccine composed of recombinant SAG1 (rSAG1) and recombinant GRA2 (rGRA2) proteins. In order to improve the induced immune responses, rSAG1 and rGRA2 were adsorbed on Poly (DL-lactide-co-glycolide) (PLGA) microspheres (MS) prepared by double emulsion solvent evaporation method. BALB/c mice were subcutaneously vaccinated by rSAG1-adsorbed PLGA MS (rSAG1-PLGA), rGRA2-adsorbed PLGA MS (rGRA2-PLGA), and the mixture of both formulations (rSAG1/rGRA2-PLGA), twice with a 3-week interval. PLGA MS characteristics, protein release, cellular and humoral immune responses, and protection against acute toxoplasmosis were evaluated. All vaccinated mice induced significantly partial protection and longer survival times associated with higher IFN-γ/IL-10 ratio and higher amount of Toxoplasma-specific IgG antibodies compared to control groups. Interestingly, the synergistic effect of rSAG1 and rGRA2 in eliciting more potent cellular and humoral responses and consequently higher protection in comparison to single antigen was confirmed. This study introduces the mixture of rSAG1 and rGRA2 (derived from different stages of Toxoplasma life-cycle) formulated in PLGA MS as a promising candidate in vaccine development against T. gondii.

Genetic diversity and effect of natural selection at apical membrane antigen-1 (AMA-1) among Iranian Plasmodium vivax isolates.

Apical membrane antigen-1 (AMA-1) of Plasmodium vivax Grassi et Feletti, 1890 is a promising malaria vaccine candidate. However, antigenic variation is a major problem to design a universal malaria vaccine. Hence, detailed understanding of the pvama-1 gene polymorphism can provide conductive information on this potential vaccine component. Therefore, this study investigated the extent of genetic polymorphisms at domain I (DI), DII and partial DIII of AMA-1 among Iranian P. vivax isolates. Out of 107 blood samples, 92 were analysed based on the quality of the sequencing data. The sequences were classified into 53 haplotypes. Amino acid changes were observed at 31 positions that 17 were located at DI, 11 were at DII and the rest of them (3 positions) were at DIII. Thus, codon polymorphisms at DI were found to be higher than DII. Also, five of these polymorphic codons (D242E, T374P, S389R, Y391F, I395F) were novel and have not been reported yet. Neutrality analysis by using the dN-dS difference (the difference between the rate of non-synonymous and synonymous mutations) showed a negative diversifying selection at DI, DII and across the length of both domains. The potential B-cell epitopes were found in 5 regions of the PvAMA-1 with 10 mutation sites (E145A, K188N, E189N/K/D, K190Q/E, P210S, E227V, D242E, R249H, G253E, K352E), whereas only one mutation (G288E) has been detected in intrinsically unstructured/disordered regions. Fixation index (Fst) estimation between Iranian and Indian isolates (0.0131) indicated a significant low genetic differentiation. Distribution of the polymorphic sites and IURs mapped on a three dimensional structure of PvAMA-1 showed that these regions were located at two opposite faces of the molecule. In conclusion, the results have significant value in the design and development of a malaria vaccine based on this antigen.

Introduction and effect of natural selection analysis at common mutations of SARS-CoV-2 spike gene in Iran.

The epidemic of coronavirus disease 2019 (COVID-19) was caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The spike (S) protein of SARS-Cov-2 is composed of two subunits, S1 and S2. This study aimed to describe SARS-CoV-2 haplotypes in Iranians based on the S gene, which plays a key role in the receptor recognition and cell membrane fusion proses. 95 positive saliva samples for SARS-CoV-2 were amplified and sequenced for the S gene. The sequences were classified into 35 haplotypes, which 11 haplotypes were new (H1, H2, H3, H4, H6, H7, H11, H13, H15, H16, H25) and have not been reported so far. Amino acid substitutions were found at 40 positions that 23 were located at S1 subunit and 16 were at S2 subunit and one was at cleavage loop (P681H/R), thus polymorphisms at S1 subunit were found to be higher than S2. The neutrality index (NI) analyses showed a negative departure from the neutral substitution patterns (NI > 1) for S1 and S2 subunit in the studied sequences. The co-occurrence of B-cell epitopes and mutation sites were found in seven positions with more probably to be exposed the immune system pressure. In conclusion, the results provide the significant data to design an effective vaccine based on this protein.

Identification of Antigenic and Immunogenic Proteins of Toxoplasma gondii in Human and Sheep by Immunoproteomics.

BACKGROUND: Toxoplasmosis is a parasitic disease caused by the intracellular protozoan parasite, Toxoplasma gondii, which can infect humans and warm-blooded animals. This infection can lead to still birth and abortion among some susceptible hosts especially sheep and human in pregnancy. Development of a vaccine against T. gondii infection is very important-especially for use in immunocompromised patients, pregnant women, and sheep. Different antigens of T. gondii can be potential candidates for immunization. The aims of this study were to identify the immunodominant and antigenic proteins of T. gondii in sheep and man. METHODS: Tachyzoites' proteins were separated by two-dimensional polyacrylamide gel electrophoresis (2-DE), and subjected to western blot analysis probed with T. gondii positive sera of sheep and human (Biotechnology Department of Pasteur Institute of Tehran, Iran, from April 2016 to March 2017). Finally, the immunoreactive proteins were identified by mass spectrometry (MALDI-TOF/MS and MS/MS) technique. RESULTS: Five immunoreactive and antigenic proteins were recognized by Toxoplasma positive sera of human and sheep. These identified proteins were Enolase 2, rhoptry protein 4 (ROP4), dense granular protein 14 (GRA14), rhoptry protein 15 (ROP15) and rhoptry protein 9 (ROP9). CONCLUSION: The identified immunodominant proteins have potential to be used as diagnostic antigens and as diagnostic markers of Toxoplasma infection in sheep and human.

Predominance of Leishmania major and rare occurrence of Leishmania tropica with haplotype variability at the center of Iran.

BACKGROUND: Leishmania major is a causative agent of zoonotic cutaneous leishmaniasis in the center of Iran, Abarkouh district. Molecular characterization and precise incrimination of Leishmania species was carried out to perform controlling measurements and to design treatment programs for zoonotic cutaneous leishmaniasis. METHODS: All smears isolated from ulcers of suspected patients were examined under a light microscope and graded for amastigotes frequency. Extraction of DNA, PCR, RFLP and sequencing of ITS-rDNA genotype were done to increase the efficacy of Leishmania parasites identification at their species-specific level and to detect any Leishmania infections within. RESULTS: Humans were found to be infected with L. major with high infection frequency and also Leishmania tropica was identified with low occurrence for the first time as non-native species using molecular analyses. The rates of infections was considerable with microscopic observation (n = 65, 73%) out of 89 smears prepared from suspected patients. Molecular analyses showed that the density of L. major was significantly higher (n = 48, 53.93%) than L. tropica (n = 4, 4.49%) (Mann-Whitney U test: p < 0.05) and two samples (2.25%) remained ambiguous after several sequencing. L. major did not have diversity with two common haplotypes but L. tropica were found to exhibit high diversity with three novel haplotypes. CONCLUSION: L. major was considered the causative agent of leishmaniasis in the region, but the identification of a non-native L. tropica revealed the importance of further isolation of Leishmania parasites following molecular analyses and confirmation, and also revealed the importance of further isolation of Leishmania parasites from patients of the field areas who do not have easily access to health care centers for specialized treatment strategies.

Analysis of Plasmodium vivax Apical Membrane Antigen-1 (PvAMA-1) Haplotypes among Iranian Isolates.

Plasmodium vivax apical membrane antigen-1(PvAMA-1) is a surface protein with polymorphic sites. This study was aimed to analyze the polymorphic amino acid residues at PvAMA-1 in different infected age groups. 92 blood samples were collected from the south and southeast of Iran. The DNA coding for the domain I (DI), DII, and partial DIII of this antigen was amplified by Nested-PCR, and sequenced. Nucleotide mutations were found in 49 sites and based on the amino acid sequence, 30 variable sites were detected. Age distribution of malaria cases showed that the majority of the patients were between 10 to 30 years old. The scattering plot haplotypes by age showed an increasing incidence rate with age during childhood, whereas, incidence was the lowest in patients under five years old. Comparison of the polymorphic sites of PvAMA-1 in Iranian isolates with those found in other geographic regions of the world indicated nine common variable positions. In addition, a significant dependence was found between some particular substitutions and age categories. Dependence between particular substitutions and age groups suggests that certain residues in AMA-1 are responsible for clinical attacks in different ages, likely as a result of host immune pressure. The crystal structure of the PvAMA-1 showed that the amino acid substitutions that changed the protein charge were exclusively located in loops and turns where, the interactions with antibodies could occur. These data provide the necessary information for an AMA-1 based malaria vaccine design to be effective across all ages.

Evaluative Assay of Nuclear and Mitochondrial Genes to Diagnose Leishmania Species in Clinical Specimens.

BACKGROUND: Leishmaniasis as an emerging and reemerging disease is increasing worldwide with high prevalence and new incidence in recent years. For epidemiological investigation and accurate identification of Leishmania species, three nuclear and mitochondrial genes (ITS-rDNA, Hsp70, and Cyt b) were employed and analyzed from clinical samples in three important Zoonotic Cutaneous Leishmaniasis (ZCL) foci of Iran. METHODS: In this cross-sectional/descriptive study conducted in 2014-15, serous smears of lesions were directly prepared from suspected patients of ZCL in Turkmen in northeast, Abarkouh in center and Shush district in southwest of Iran. They were directly prepared from suspected patients and DNA was extracted. Two nuclear genes of ITS-rDNA, Hsp70 and one mitochondrial gene of Cyt b within Leishmania parasites were amplified. RFLP was performed on PCR-positive samples. PCR products were sequenced, aligned and edited with sequencher 4.1.4 and phylogenic analyses performed using MEGA 5.05 software. RESULTS: Overall, 203 out of 360 clinical samples from suspected patients were Leishmania positive using routine laboratory methods and 231 samples were positive by molecular techniques. L. major L. tropica, and L. turanica were firmly identified by employing different molecular genes and phylogenic analyses. CONCLUSION: By combining different molecular genes, Leishmania parasites were identified accurately. The sensitivity and specificity three genes were evaluated and had more advantages to compare routine laboratory methods. ITS-rDNA gene is more appropriate for firm identification of Leishmania species.

Controlled release of an endostatin peptide using chitosan nanoparticles.

Whereas several anticancer peptides are in different stages of clinical development, their administration is limited by the fast elimination from the systemic circulation. Peptide loading on nano-carriers can pave the way for their future application. We have recently indicated that a disulfide loop rather than a Zn-binding loop improves the anti-angiogenic and antitumor activities of the N-terminal fragment of endostatin. In this study, chitosan nanoparticles (CS NPs) are used for the controlled release of the engineered peptide. Loading of the peptide into CS NPs using the ionic gelation method was confirmed by FTIR and resulted in final particle size, poly-dispersity index and surface charge of 186.5 ± 24.0 nm, 0.26 ± 0.02 and 20.1 ± 0.4 mV respectively. The SEM morphological analysis revealed spherical particles with an average size of 80 ± 5 nm. Peptide loading studies revealed that CS NPs are able to adsorb the peptide as ~70%. The release measurements indicated an initial burst release by 49% after 2 hr and complete release after 80 hr. According to in vitro studies, the loaded peptide was much more toxic for endothelial cells than different cancer cell lines. These results underscore the promise of CS NPs as therapeutics nanosystems and open a perspective for improving the clinical applications of peptide drugs.

Expression, purification and in vitro refolding of the recombinant truncated Saposin-like protein 2 antigen for development of diagnosis of human fascioliasis.

Early diagnosis of fascioliasis is critical in prevention of injury to the liver and bile ducts. Saposin-like protein (FhSAP-2) is probably the most ideal antigen of Fasciola hepatica for development of ELISA kits. SAP-2 has a conserved tertiary structure containing three disulfide bonds and conformational epitopes. Therefore, antigenicity of SAP-2 is greatly depends on disulfide bond formation and proper folding. We produced the recombinant truncated SAP-2 (rtSAP-2) in the SHuffle® T7 and Rosetta strain of Escherichia coli, in soluble and insoluble forms, respectively and purified by immobilized metal affinity chromatography (IMAC). The refolding process of denatured rtSAP-2 was performed using dialysis and dilution methods in the presence of chemical additives, along with reduced/oxidized glutathione (in vitro). Physicochemical studies, including non-reducing gel electrophoresis, Ellman's assay, Western blotting and ELISA showed the most antigenicity and likely correct folding of rtSAP-2, which was obtained by dialysis method. An IgG ELISA test was developed using rtSAP-2 refolded by dialysis and compared with excretory/secretory products of parasite with 52 positive fascioliasis samples, 79 other parasitic samples and 70 negative controls samples. The results exhibited 100% sensitivity and 98% specificity for rtSAP-2, also, 100% and 95.3% for excretory/secretory (E/S) antigen, respectively. In conclusion, it is suggested that rtSAP-2 with the correct folding could be used as a candidate antigen for detection of human fascioliasis.

Seroprevalence and risk factors for Toxoplasma gondii infection among pregnant women in Northeast Iran.

We report Toxoplasma IgG seroprevalence of 34.4% among 419 pregnant women in Mashhad, northeast Iran. Soil contact, living in rural environment, and level of education were associated with infection. The prevalence did not increase with age, suggesting high infection rate during childhood and adolescence.

Predominance of Leishmania major and rare occurrence of Leishmania tropica with haplotype variability at the center of Iran

ABSTRACT Background Leishmania major is a causative agent of zoonotic cutaneous leishmaniasis in the center of Iran, Abarkouh district. Molecular characterization and precise incrimination of Leishmania species was carried out to perform controlling measurements and to design treatment programs for zoonotic cutaneous leishmaniasis. Methods All smears isolated from ulcers of suspected patients were examined under a light microscope and graded for amastigotes frequency. Extraction of DNA, PCR, RFLP and sequencing of ITS-rDNA genotype were done to increase the efficacy of Leishmania parasites identification at their species-specific level and to detect any Leishmania infections within. Results Humans were found to be infected with L. major with high infection frequency and also Leishmania tropica was identified with low occurrence for the first time as non-native species using molecular analyses. The rates of infections was considerable with microscopic observation (n= 65, 73%) out of 89 smears prepared from suspected patients. Molecular analyses showed that the density of L. major was significantly higher (n= 48, 53.93%) than L. tropica (n= 4, 4.49%) (Mann-Whitney U test: p< 0.05) and two samples (2.25%) remained ambiguous after several sequencing. L. major did not have diversity with two common haplotypes but L. tropica were found to exhibit high diversity with three novel haplotypes. Conclusion L. major was considered the causative agent of leishmaniasis in the region, but the identification of a non-native L. tropica revealed the importance of further isolation of Leishmania parasites following molecular analyses and confirmation, and also revealed the importance of further isolation of Leishmania parasites from patients of the field areas who do not have easily access to health care centers for specialized treatment strategies.