Protective immunity induced with a DNA vaccine encoding B- and T-cells multi-epitope SAG1, ROP16, MIC4, GRA12, M2AP, and multi-epitope ROP8 against acute and chronic toxoplasmosis in BALB/c mice.

BACKGROUND: T. gondii infection is characterized by a high global prevalence. Nearly, 16-40% of people have been infected by T. gondii. Although T. gondii often causes subclinical infection, it may cause severe complications in newborns with congenital infection and immunocompromised individuals. Constant attempts of scientists have made valuable findings in the development of T. gondii candidate vaccines. However, an effective vaccine has not been successfully developed yet. In this study, multi-epitope SAG1, MIC4, ROP16, M2AP, GRA12, and multi-epitope ROP8 were injected into BALB/c mice intramuscularly, as cocktailed plasmids or as single-gene plasmids to assess the immune response against chronic and acute Toxoplasma infection. METHODS: BALB/c mice were immunized on days 0, 21, and 42. The immune responses of both vaccinated and control groups were evaluated using cytokine and antibody measurements, lymphocyte proliferation assay, survival time, and average number of cysts in each brain. RESULTS: The results indicated that DNA vaccination using multi-epitope ROP8 and multi-epitope SAG1, ROP16, MIC4, GRA12, M2AP could elicit both cellular and humoral immune responses, and enhanced the survival time in BALB/c mice. Also, the administration of multi-epitope ROP8 plus multi-epitope SAG1, ROP16, MIC4, GRA12, M2AP could enhance the concentrations of IgG antibody, elicit a mixed IgG1/IgG2a reaction with the predominance of the IgG2a, increase the release of IFN-γ cytokine, prolonge the survival time, and reduce the brain cysts. CONCLUSIONS: Here, we report that vaccination using cocktailed plasmids could induce better protective immunity compared to single plasmid for acute and chronic T. gondii infection.

Detection of Anti-Toxoplasma gondii IgG and IgM Antibodies and Associated Risk Factors during Pregnancy in Southwest Iran.

Background: This research was aimed at evaluating the seroprevalence of acute and chronic Toxoplasma gondii (T. gondii) infection in pregnant women and related risk factors in southwest Iran. Methods: In this cross-sectional study, eighty-eight pregnant women were included from October 2019 to December 2019. The presence of anti-T. gondii IgM and IgG antibodies was measured using the enzyme-linked immunosorbent assay (ELISA). In addition, a questionnaire consisting of demographic information was completed for each subject. Results: The overall seroprevalence of T. gondii infection was estimated to be 34.09% (30/88). Of these, 1 (1.13%) and 29 (32.95%) samples were found positive for IgM and IgG, respectively. Regarding the risk factors, the consumption of raw/undercooked meat (P value = 0.007) and history of abortion (P value = 0.017) were significantly associated with IgG seroprevalence in pregnant women. Conclusion: The results showed that the pregnant women of southwest Iran might be moderately exposed to T. gondii. Since the risk of acute T. gondii infection in this susceptible group is very important, regular screening tests to diagnose the infection are recommended before pregnancy.

Computational probing of Toxoplasma gondii major surface antigen 1 (SAG1) for enhanced vaccine design against toxoplasmosis.

The SAG1 is a tachyzoite-specific protein critical for Toxoplasma gondii (T. gondii) adhesion to surface receptors of the host cells. In this study we've comprehensively excavated the sequence of SAG1 using online bioinformatics servers toward better vaccine design against toxoplasmosis. Web-based tools were used to assess the physico-chemical properties, post-translational modifications (PTMs), transmembrane domains, subcellular localization, secondary and 3D structures, as well as B-cell, Cytotoxic T cells (CTL) and major histocompatibility complex (MHC) epitopes. The 336 amino acid sequence possessed a molecular weight of 34829.02 D, aliphatic index of 80.15 and GRAVY score of 0.129. There was 47 PTM sites without any transmembrane domains. Also, the SAG1 protein was appointed to be immunogen and non-allergen. The secondary structure comprised 62.5% random coil, 26.79% extended strand and 10.71% alpha helix. Ramachandran plot of the refined model demonstrated 94.4% residues in the favored region, 4.8% in allowed region and 0.8% in outlier region. Additionally, various potential B-cell (linear and conformational), CTL and HTL epitopes were predicted for T. gondii SAG1. This in silico investigation would be a premise for appropriate immunization strategies against toxoplasmosis. More studies are anticipated to be done empirically using SAG1 immunoprotective epitopes combined with other antigenic compounds.

Structural predication and antigenic analysis of ROP16 protein utilizing immunoinformatics methods in order to identification of a vaccine against Toxoplasma gondii: An in silico approach.

Toxoplasmosis, caused by Toxoplasma gondii, is a common parasitic disease, affecting almost one-third of the world's population. Currently, there are no effective treatments for inhibiting the formation of chronic tissue cysts in infected hosts. Thus, the production of appropriate vaccines against this pathogen is an important goal to avoid toxoplasmosis. considering the role of rhoptry antigens like ROP16 in virulence and satisfactory immunogenicity, they can be used as promising vaccine candidates against T. gondii. In the present study, an in silico approach was used to analyze various aspects of the ROP16 protein, including physicochemical characteristics, the potential epitopes of B and T-cells, the secondary and tertiary structure, the subcellular localization, the transmembrane domain, and other important features of this protein using several bioinformatics tools to design a proper vaccine against T. gondii. The results showed that ROP16 protein includes 93 potential post-translational modification sites. The secondary structure of the ROP16 protein comprises 34.23% alpha-helix, 54.46% random coil, and 11.32% extended strand. Moreover, several potential B- and T-cell epitopes were identified for ROP16. Based on the results of Ramachandran plot, 84.64% of the amino acid residues were located in the favored, 10.34% in allowed, and 5.02% in outlier regions. Furthermore, the results of the antigenicity and allergenicity assessment noted that this protein was immunogenic and non-allergenic. Our findings suggested that structural and functional predictions applied to ROP16 protein using in silico tools can reduce the failure risk of the laboratory studies. This research provided an important basis for further studies and also developed an effective vaccine against acute and chronic toxoplasmosis by various strategies. Further studies are needed on the development of vaccines in vivo using ROP16 alone or in combination with other antigens in the future.

Toxoplasma gondii ROP38 protein: Bioinformatics analysis for vaccine design improvement against toxoplasmosis.

Rhoptry proteins (ROPs) play a significant role in various stages of Toxoplasma gondii (T. gondii) life cycle, being critical for both invasion and intracellular survival. ROP38 is a key manipulator of host gene expression and has a function in tachyzoite to bradyzoite conversion. In this study, we've employed various bioinformatics online tools for immunogenicity prediction of ROP38 protein, comprising physico-chemical, antigenic and allergenic profiles, transmembrane domain, subcellular localization, post-translational modification (PTM) sites, secondary and 3D structure, B-cell, MHC-binding and cytotoxic T-lymphocyte (CTL) epitopes. The findings showed 54 PTM sites without a transmembrane domain. Also, ROP38 was proved a non-allergenic and antigenic protein. The protein had Sec signal peptide (Sec/SPI) with 0.8762 likelihood. The secondary structure included 52.68% random coil, 29.57% alpha helix and 17.74% extended strand. Based on Ramachandran plot output for refined model, 95.3%, 3.4%, and 1.4% of amino acid residues were incorporated in the favored, allowed, and outlier regions, respectively. B-cell epitopes TFPGDDIQTSS (67-72) and KAKNKWGRTRYTLQG (207-221) as well as T-cell epitope LSPVGFFTAL (6-15) possessed the highest antigenic index in the protein sequence. This paper is a premise for further researches, and provides insights for the development of a suitable vaccine against toxoplasmosis. More empirical studies are required using the ROP38 alone or in combination with other antigens/epitopes in the future.

Immunoinformatics studies and design of a novel multi-epitope peptide vaccine against Toxoplasma gondii based on calcium-dependent protein kinases antigens through an in-silico analysis.

Purpose: Infection by the intracellular apicomplexan parasite Toxoplasma gondii has serious clinical consequences in humans and veterinarians around the world. Although about a third of the world's population is infected with T. gondii, there is still no effective vaccine against this disease. The aim of this study was to develop and evaluate a multimeric vaccine against T. gondii using the proteins calcium-dependent protein kinase (CDPK)1, CDPK2, CDPK3, and CDPK5. Materials and Methods: Top-ranked major histocompatibility complex (MHC)-I and MHC-II binding as well as shared, immunodominant linear B-cell epitopes were predicted and linked using appropriate linkers. Moreover, the 50S ribosomal protein L7/L12 (adjuvant) was mixed with the construct's N-terminal to increase the immunogenicity. Then, the vaccine's physicochemical characteristics, antigenicity, allergenicity, secondary and tertiary structure were predicted. Results: The finally-engineered chimeric vaccine had a length of 680 amino acids with a molecular weight of 74.66 kDa. Analyses of immunogenicity, allergenicity, and multiple physiochemical parameters indicated that the constructed vaccine candidate was soluble, non-allergenic, and immunogenic, making it compatible with humans and hence, a potentially viable and safe vaccine candidate against T. gondii parasite. Conclusion: In silico, the vaccine construct was able to trigger primary immune responses. However, further laboratory studies are needed to confirm its effectiveness and safety.

In vitro and in vivo study on antiprotozoal activity of calcium oxide (CaO) and magnesium oxide (MgO) nanoparticles on promastigote and amastigote forms of Leishmania major.

BACKGROUND: Currently, anti-leishmanial drugs have been developed. However, the available compounds have several side effects such as drug resistance and toxicity that cause some limitation for use. The development of nanoparticles (NPs) use in biological research and the proven effectiveness of CaONPs and MgONPs on bacteria and fungi, along with the lack of information about its antileishmanial effects, have motivated this study. CaO and MgONPs possess considerable antibacterial effects because of their alkalinity and active oxygen species. This study has taken into account the impacts of these two NPs on the L. major in vitro and in vivo. METHODS: To evaluate the antileishmanial activity of NPs, the cytotoxic effect of CaONPs, MgONPs, and MgOCaONPs against L. major amastigotes, promastigotes, as well as macrophages, was evaluated using counting or MTT assay. The possible apoptosis of L. major by CaONPs, MgONPs, and MgOCaONPs was evaluated via flow cytometry assay. For in vivo study, BALB/c mice were allocated to five groups and the lesions of infected mice with L. major promastigotes were treated with a 200 µg/mL concentration CaONPs, MgONPs, and MgOCaONPs, then the mice underwent a 4-week follow-up to examine the wound diameter and survival rates. RESULTS: The XRD-pattern related to CaONPs and MgONPs indicating the cubic phase and Rocksalt cubic structures. According the effects of nanoparticle on promastigotes the IC50 values of CaONPs, MgONPs, and MgOCaONPs within 72 h were 7.9 ug/mL, 10.3 ug/mL, and 8.0 ug/mL respectively. CaONPs, MgONPs, and MgOCaONPs induced apoptosis in about 7.8%, 53.57%, and 12.8% of promastigotes. All mice presented lesions. MgONPs was the most effective in reducing the size of the lesions. CONCLUSION: According to the results of the present research, MgONPs and CaONPs showed good in vitro and in vivo effects on L. major promastigotes and intracellular amastigotes especially MgONPs, and also it seems that MgONPs are applicable in Leishmania infection treatment due to their potential antileishmanial effects.

Immunoinformatic analysis of immunogenic B- and T-cell epitopes of MIC4 protein to designing a vaccine candidate against Toxoplasma gondii through an in-silico approach.

PURPOSE: Toxoplasmosis, transmitted by Toxoplasma gondii, is a worldwide parasitic disease that affects approximately one-third of the world's inhabitants. Today, there are no appropriate drugs to deter tissue cysts from developing in infected hosts. So, developing an effective vaccine would be valuable to avoid from toxoplasmosis. Considering the role of microneme antigens such as microneme protein 4 (MIC4) in T. gondii pathogenesis, it can be used as potential candidates for vaccine against T. gondii. MATERIALS AND METHODS: In this study several bioinformatics methods were used to assess the different aspects of MIC4 protein such as secondary and tertiary structure, physicochemical characteristics, the transmembrane domains, subcellular localization, B-cell, helper-T lymphocyte, cytotoxic-T lymphocyte epitopes, and other notable characteristic of this protein design a suitable vaccine against T. gondii. RESULTS: The studies revealed that MIC4 protein includes 59 potential post-translational modification sites without any transmembrane domains. Moreover, several probable epitopes of B- and T-cells were detected for MIC4. The secondary structure comprised 55.69% random coil, 5.86% beta-turn, 19.31% extended strand, and 19.14% alpha helix. According to the Ramachandran plot results, 87.42% of the amino acid residues were located in the favored, 9.44% in allowed, and 3.14% in outlier regions. The protein allergenicity and antigenicity revealed that it was non-allergenic and antigenic. CONCLUSION: This study gives vital basic on MIC4 protein for further research and also established an effective vaccine with different techniques against acute and chronic toxoplasmosis.

Bioinformatics analysis of calcium-dependent protein kinase 4 (CDPK4) as Toxoplasma gondii vaccine target.

OBJECTIVES: Toxoplasma gondii (T. gondii), an obligate intracellular apicomplexan parasite, could affect numerous warm-blooded animals, such as humans. Calcium-dependent protein kinases (CDPKs) are essential Ca2+ signaling mediators and participate in parasite host cell egress, outer membrane motility, invasion, and cell division. RESULTS: Several bioinformatics online servers were employed to analyze and predict the important properties of CDPK4 protein. The findings revealed that CDPK4 peptide has 1158 amino acid residues with average molecular weight (MW) of 126.331 KDa. The aliphatic index and GRAVY for this protein were estimated at 66.82 and - 0.650, respectively. The findings revealed that the CDPK4 protein comprised 30.14% and 34.97% alpha-helix, 59.84% and 53.54% random coils, and 10.02% and 11.49% extended strand with SOPMA and GOR4 tools, respectively. Ramachandran plot output showed 87.87%, 8.40%, and 3.73% of amino acid residues in the favored, allowed, and outlier regions, respectively. Also, several potential B and T-cell epitopes were predicted for CDPK4 protein through different bioinformatics tools. Also, antigenicity and allergenicity evaluation demonstrated that this protein has immunogenic and non-allergenic nature. This paper presents a basis for further studies, thereby provides a fundamental basis for the development of an effective vaccine against T. gondii infection.

Immunoinformatic Analysis of Calcium-Dependent Protein Kinase 7 (CDPK7) Showed Potential Targets for Toxoplasma gondii Vaccine.

Apicomplexan parasites, including Toxoplasma gondii (T. gondii), express different types of calcium-dependent protein kinases (CDPKs), which perform a variety of functions, including attacking and exiting the host cells. In the current bioinformatics study, we have used several web servers to predict the basic features and specifications of the CDPK7 protein. The findings showed that CDPK7 protein has 2133 amino acid residues with an average molecular weight (MW) of 219085.79 D. The aliphatic index with 68.78 and grand average of hydropathicity (GRAVY) with -0.331 score were estimated. The outcomes of current research showed that the CDPK7 protein included 502 alpha-helix, 1311 random coils, and 320 extended strands with GOR4 method. Considering the Ramachandran plot, the favored region contains more than 92% of the amino acid residues. In addition, evaluation of antigenicity and allergenicity showed that CDPK7 protein has immunogenic and nonallergenic nature. The present research provides key data for more animal-model study on the CDPK7 protein to design an efficient vaccine against toxoplasmosis in the future.

The first Report of Faustula keksooni from Tenualosa ilisha in Karun River, Southwest of Iran.

BACKGROUND: Tenualosa ilisha (ilish, hilsa, hilsa herring, or hilsa shad) is a species of migratory fish in the herring family (Clupeidae), and is considered as a popular food fish in the southwest of Iran. OBJECTIVE: Due to the high consumption of T. ilisha fish in Khuzestan province (especially in Abadan and Khorramshahr cities) and lack of any reports about the intestinal trematode of this fish; the current study was aimed to investigate the trematode parasites of T. ilisha. METHODS: For this purpose, a total of 50 T. ilisha fishes were collected from the Karun River during Feb-Mar 2017. The fishes were transferred to the Department of Medical Parasitology of Tarbiat Modares University and dissected to obtain the intestine. The intestines were extensively searched for the presence of trematode and after parasites recovering, they were preserved in 70% alcohol. Moreover, the helminths were stained by acetic carmine. The parasites were identified with the aid of reliable sources. RESULTS: Forty-one out of 50 (82%) fishes were found to be positive for trematode. The recovered trematode belonged to Faustula keksooni. CONCLUSION: The present study showed a high burden of infection in T. ilisha. It should be noted that we reported F. keksooni for the first time in Iran.

Antigenic properties of dense granule antigen 12 protein using bioinformatics tools in order to improve vaccine design against Toxoplasma gondii.

PURPOSE: Toxoplasma gondii is an opportunistic parasite infecting all warm-blooded animals including humans. The dense granule antigens (GRAs) play an important role in parasite survival and virulence and in forming the parasitophorous vacuole. Identification of protein characteristics increases our knowledge about them and leads to develop the vaccine and diagnostic studies. MATERIALS AND METHODS: This paper gave a comprehensive definition of the important aspects of GRA12 protein, including physico-chemical features, a transmembrane domain, subcellular position, secondary and tertiary structure, potential epitopes of B-cells and T-cells, and other important features of this protein using different and reliable bioinformatics methods to determine potential epitopes for designing of a high-efficient vaccine. RESULTS: The findings showed that GRA12 protein had 53 potential post-translational modification sites. Also, only one transmembrane domain was recognized for this protein. The secondary structure of GRA12 protein comprises 35.55% alpha-helix, 19.50% extended strand, and 44.95% random coil. Moreover, several potential B- and T-cell epitopes were identified for GRA12. Based on the results of the Ramachandran plot, 79.26% of amino acid residues were located in favored, 11.85% in allowed and 8.89% in outlier regions. Furthermore, the results of the antigenicity and allergenicity assessment noted that GRA12 is immunogenic and non-allergenic. CONCLUSION: This research provided important basic and conceptual data on GRA12 to develop an effective vaccine against acute and chronic toxoplasmosis for further in vivo investigations. More studies are required on vaccine development using the GRA12 alone or combined with other antigens in the future.

In-depth computational analysis of calcium-dependent protein kinase 3 of Toxoplasma gondii provides promising targets for vaccination.

PURPOSE: The Toxoplasma gondii calcium-dependent protein kinase-3 (CDPK3) is a key enzyme for parasite egress, control of calcium-dependent permeabilization in parasitophorous vacuole membrane and tissue cyst formation. In this study, we comprehensively explored the bioinformatics features of this protein to improve vaccine design against T. gondii. MATERIALS AND METHODS: Various web servers were employed for the analysis of physico-chemical properties, post-translational modifications, localization in the subcellular milieu, secondary and tertiary structures, as well as B-cell, major histocompatibility complex (MHC)-binding and cytotoxic T-lymphocyte (CTL) epitopes. RESULTS: This protein was a 537 amino acid antigenic and non-allergenic molecule with a molecular weight of 60.42 kDa, a grand average of hydropathicity score of -0.508, and aliphatic index of 79.50. There exists 46.74% alpha helix, 12.48% extended strand, and 40.78% random coil in the secondary structure. Ramachandran plot of the refined model demonstrated 99.3%, 0.7%, and 0.0% of residues in the favored, allowed and outlier areas, respectively. Besides, various potential B-cell (continuous and conformational), MHC-binding and CTL epitopes were predicted for Toxoplasma CDPK3 protein. CONCLUSION: This article provides a foundation for further investigations, and laid a theoretical basis for the development of an appropriate vaccine against T. gondii infection.