Association of killer cell immunoglobulin-like receptors and their cognate HLA class I ligands with susceptibility to acute myeloid leukemia in Iranian patients.

Acute myeloid leukemia (AML) is one of the most prevalent leukemia in adults. Among the various NK receptors, killer immunoglobulin-like receptors (KIRs) carry out indispensable roles in NK cell development and function through engaging with class I human leukocyte antigens (HLA-I) as their ligands. Besides divergent KIR and HLA loci, KIR/HLA-I combinations have a significant effect on NK cell response. In this case-control study, we aimed to verify the association of KIR/HLA-I combinations with susceptibility to AML in the Southwestern Iranian population. KIR and HLA genotyping was performed with PCR-SSP by some novel primers for 181 patients with AML and 181 healthy controls. According to our results, the frequencies of KIR3DS1 (p = 0.0001, OR = 2.32, 95% CI 1.51-3.58), KIR2DS4fl (p = 0.02, OR = 1.53, 95% CI 1.05-2.21), CxT4 genotypes (p = 0.03, OR = 2.0, 95% CI 1.05-3.82), and T4 gene cluster (p = 0.01, OR = 1.99, 95% CI 1.17-3.41) were significantly higher in patients than controls, while C1/C2 genotype (p = 0.00002, OR = 0.39, 95% CI 0.25-0.61), HLA-A Bw4 (p = 0.02, OR = 0.6, 95% CI 0.38-0.94), and HLA-A*11 (p = 0.03, OR = 0.57, 95% CI 0.34-0.95) alleles were more frequent in controls. In addition, inhibitory (i)KIR/HLA-I combinations analysis revealed higher frequencies of KIR2DL1( +)/HLA-C2( +), KIR2DL2/3( +)/HLA-C1( +), KIR3DL1( +)/HLA-A Bw4( +), and KIR3DL2( +)/HLA-A*03/11( +) in the control group (p = 0.002, OR = 0.49, 95% CI 0.3-0.78; p = 0.04, OR = 0.62, 95% CI 0.39-0.99; p = 0.04, OR = 0.63, 95% CI 0.4-0.99; and p = 0.03, OR = 0.62, 95% CI 0.4-0.95, respectively). Overall, the number of iKIR/HLA-I combinations was more in the control group. Moreover, KIR3DS1( +)/HLA-B Bw4Ile80( +) and the sum of HLA-B Bw4/A Bw4 combined with KIR3DS1 as activating KIR/HLA-I combinations were more frequent among patients than controls (p = 0.01, OR = 1.99, 95% CI 1.14-3.49 and p = 0.005, OR = 1.97, 95% CI 1.22-3.19, respectively). In conclusion, our results postulate that inhibitory combinations play a protective role against AML by developing potent NK cells during education. It is noteworthy that KIR/HLA-I combination studies can be applicable in donor selection for allogeneic NK cell therapy in hematological malignancies.

Current advances in stem cell therapy in the treatment of multiple sclerosis.

Multiple sclerosis (MS) is an inflammatory disease related to the central nervous system (CNS) with a significant global burden. In this illness, the immune system plays an essential role in its pathophysiology and progression. The currently available treatments are not recognized as curable options and, at best, might slow the progression of MS injuries to the CNS. However, stem cell treatment has provided a new avenue for treating MS. Stem cells may enhance CNS healing and regulate immunological responses. Likewise, stem cells can come from various sources, including adipose, neuronal, bone marrow, and embryonic tissues. Choosing the optimal cell source for stem cell therapy is still a difficult verdict. A type of stem cell known as mesenchymal stem cells (MSCs) is obtainable from different sources and has a strong immunomodulatory impact on the immune system. According to mounting data, the umbilical cord and adipose tissue may serve as appropriate sources for the isolation of MSCs. Human amniotic epithelial cells (hAECs), as novel stem cell sources with immune-regulatory effects, regenerative properties, and decreased antigenicity, can also be thought of as a new upcoming contender for MS treatment. Overall, the administration of stem cells in different sets of animal and clinical trials has shown immunomodulatory and neuroprotective results. Therefore, this review aims to discuss the different types of stem cells by focusing on MSCs and their mechanisms, which can be used to treat and improve the outcomes of MS disease.

In silico Prediction and Evaluation of Human Parainfluenza Virus-3 CD4+ T Cell Epitopes.

BACKGROUND: Human parainfluenza viruses type 3 (HPIV-3) through bronchiolitis and pneumonia is a common cause of lower respiratory tract infections. It is the main cause of hospitalization of infants and young children and also one of the main causes of morbidity and mortality in immuno-compromised and transplant patients. Despite many efforts, there is currently no specific anti-HPIV-3 drug or approved vaccine to prevent and control the virus. Identification of HPIV-3 epitopes with the capability of binding to human leukocyte antigen (HLA) class II molecules can be helpful in designing new vaccine candidates against HPIV-3 infection, and also can be useful for the in vitro stimulation and proliferation of HPIV-3-specific T cells for transplant and immunocompromised patients. OBJECTIVE: To predict and comprehensively evaluate CD4+T cell epitope (HLA-II binders) from four main HPIV-3 antigens. METHODS: In the present work, we predicted and comprehensively evaluated CD4+T cell epitope (HLA-II binders) from four main HPIV-3 antigens, including fusion protein (F), hemagglutininneuraminidase (HN), nucleocapsid (N) and matrix (M) proteins using bio- and immunoinformatics software. The toxicity, allergenicity, Blast screening and population coverage of the predicted epitopes were evaluated. The binding ability of the final selected epitopes was evaluated via a docking study. RESULTS: After several filtering steps, including blast screening, toxicity and allergenicity assay, population coverage and docking study, 9 epitopes were selected as candidate epitopes. The selected epitopes showed high population coverage and docking studies revealed a significantly higher binding affinity for the final epitopes in comparison with the negative control peptides. CONCLUSION: The final selected epitopes could be useful in designing vaccine candidates and for the treatment of immune-compromised individuals and patients with transplantation.

Designing and Characterization of Tregitope-Based Multi-Epitope Vaccine Against Multiple Sclerosis: An Immunoinformatic Approach.

BACKGROUND: Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system(CNS). It is widely accepted that the development and progression of MS result from aberrant activation of potentially encephalitogenic reactive-T cells against CNS antigens. The pathologic roles of both CD4+ (T helper; Th) and CD8+ T cells have been demonstrated in MS lesions. OBJECTIVE: In the present work, we applied a series of bioinformatics tools to design a dendritic cell (DC)-targeting Tregitope-based multi-epitope vaccine for MS to induce tolerance in pathogenic myelin-specific T cells. METHODS: The 3D structure of anti-DEC205 scFv and the remaining part of the vaccine were modeled by ROSIE Antibody server and ITASSER software, respectively. AIDA web server (ab initio domain assembly server) was applied to assemble two parts of the vaccine and build the full construct. Following modeled structure refinement and validation, physicochemical properties, and allergenicity of the vaccine were assessed. In the final step, in silico cloning was done to ensure high-level expression in the desired host. RESULTS: This vaccine consists of three main parts; 1) Anti-DEC205 scFv antibody, 2) multiepitope vaccine part composed of multiple pathogenic CD4+, and CD8+ T cell epitopes originated from multiple known antigens in MS patients, as well as T-regulatory (Treg)-inducing epitopes (Tregitopes), and 3) vasoactive intestinal peptide (VIP). All parts of the final vaccine were joined together with the help of proper linkers. After vaccine construction, the three-D structure, as well as different physicochemical and immunological features of the vaccine were predicted. Finally, in silico gene cloning was also carried out to assure efficient production of protein vaccine in Escherichia coli K12 expression strain. CONCLUSION: Computational study revealed that this vaccination can regulate MS disease progression and even relapse by harnessing pathogenic T cells.

Bioinformatics analysis for the purpose of designing a novel multi-epitope DNA vaccine against Leishmania major.

Leishmaniasis is one of the main infectious diseases worldwide. In the midst of all the different forms of the disease, Cutaneous Leishmania (CL) has the highest incidence in the world. Many trial vaccines have been developed with the purpose of generating long-term cell-mediated immunity to Leishmania(L) major. As there is not any multi-epitope DNA vaccine with high efficacy against L.major, the aim of this study is to design a new multi-epitope DNA vaccine in order to have effective control upon this infectious disease through the immune bioinformatics. The L.major antigens: Gp63, LACK, TSA, LmSTI1and KMP11 were selected to design a multi-epitope DNA vaccine. The initial structure of the DNA vaccine was designed, benefiting from Gen Bank's website information. Epitopes of MHC-I antigens were predicted through the Immune Epitope Database (IEDB), and the selected epitopes were used to make vaccines construct along with linkers. New multi-epitope vaccine including 459 nucleic acids designed, and inserted between BamH1 and HindIII restriction sites of pCDNA3.1 mammalian expression vector. 12 epitopes among the chosen antigens were selected by two servers (IEDB and ANTIGEN). They had high stability and high antigenic power. Physicochemical features of vaccine measured by ProtParam server, and this structure was thermostable and hydrophilic. it's a suitable model to study on the animal and human phases. The designed vaccine is expected to be an effective candidate through development of (CL) vaccines. However, the effectiveness of this vaccine should also evaluate in vivo model.

Development of Human Recombinant Antibodies Against ROR1 Tumor Antigen.

Background: Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an oncofetal antigen expressed on many types of cancer cells, but not normal adult cells. ROR1 antigen contributes to cancer development and progression by several signaling pathways. ROR1 expression has been associated with tumor growth, survival, and metastasis. In this study specific human recombinant antibodies were selected against ROR1 antigen for their use in cancer immunotherapy. Methods: Phage display technology was used to produce phage antibody from a human scFv library. Phage concentration was determined to confirm the phage rescue process. Panning procedure was performed to isolate specific scFv clones against ROR1 epitope. Phage ELISA was done to evaluate the reactivity of the selected scFvs. Results: Two specific human scFvs with frequencies of 20% and 25% were selected against ROR1 peptide. The antibodies showed specific reaction to the corresponding epitopes in phage ELISA. Discussion: Cancer targeted therapy using human specific antibodies is a new strategy, which is used in cancer therapy. The selected specific scFvs that target ROR1 epitope are human antibodies that originated from a human library and have the potential to be used in clinic in cancer immunotherapy of ROR1 positive tumors without induction of human anti mouse antibody (HAMA) response.

Maximizing the recovery of the native p28 bacterial peptide with improved activity and maintained solubility and stability in Escherichia coli BL21 (DE3).

p28 is a natural bacterial product, which recently has attracted much attention as an efficient cell penetrating peptide (CPP) and a promising anticancer agent. Considering the interesting biological qualities of p28, maximizing its expression appears to be a prominent priority. The optimization of such bioprocesses might be facilitated by utilizing statistical approaches such as Design of Experiment (DoE). In this study, we aimed to maximize the expression of "biologically active" p28 in Escherichia coli BL21 (DE3) host by harnessing statistical tools and experimental methods. Using Minitab, Plackett-Burman and Box-Behnken Response Surface Methodology (RSM) designs were generated to optimize the conditions for the expression of p28. Each condition was experimentally investigated by assessing the biological activity of the purified p28 in the MCF-7 breast cancer cell line. Seven independent variables were investigated, and three of them including ethanol concentration, OD600 of the culture at the time of induction, and the post-induction temperature were demonstrated to significantly affect the p28 expression in E. coli. The cytotoxicity, penetration efficiency, and total process time were measured as dependent variables. The optimized expression conditions were validated experimentally, and the final products were investigated in terms of expression yield, solubility, and stability in vitro. Following the optimization, an 8-fold increase of the concentration of p28 expression was observed. In this study, we suggest an optimized combination of effective factors to produce soluble p28 in the E. coli host, a protocol that results in the production of a significantly high amount of the biologically active peptide with retained solubility and stability.

Utilization of SUMO Tag and Freeze-thawing Method for a High-level Expression and Solubilization of Recombinant Human Angiotensinconverting Enzyme 2 (rhACE2) Protein in E. coli.

BACKGROUND: SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE2) as a receptor for entering the host cells. Production of the ACE2 molecule is important because of its potency to use as a blocker and therapeutic agent against SARS-CoV-2 for the prophylaxis and treatment of COVID-19. OBJECTIVE: The recombinant human ACE2 (rhACE2) is prone to form an inclusion body when expressed in the bacterial cells. METHODS: We used the SUMO tag fused to the rhACE2 molecule to increase the expression level and solubility of the fusion protein. Afterward, the freeze-thawing method plus 2 M urea solubilized aggregated proteins. Subsequently, the affinity of solubilized rhACE2 to the receptor binding domain (RBD) of the SARS-CoV-2 spike was assayed by ELISA and SPR methods. RESULTS: SUMO protein succeeded in increasing the expression level but not solubilization of the fusion protein. The freeze-thawing method could solubilize and recover the aggregated fusion proteins significantly. Also, ELISA and SPR assays confirmed the interaction between solubilized rhACE2 and RBD with high affinity. CONCLUSION: The SUMO tag and freeze- Conclusion: The SUMO tag and freeze-thawing method would be utilized for high-level expression and solubilization of recombinant rhACE2 protein.

Obesity and Adipose Tissue-derived Cytokines in the Pathogenesis of Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic autoimmune neurodegenerative disease of the central nervous system (CNS) characterized by demyelination, neuronal loss, and permanent neurological impairments. The etiology of MS is not clearly understood, but genetics and environmental factors can affect the susceptibility of individuals. Obesity or a body mass index of (BMI) > 30 kg/m2 is associated with serious health consequences such as lipid profile abnormalities, hypertension, type 2 diabetes mellitus, reduced levels of vitamin D, and a systemic lowgrade inflammatory state. The inflammatory milieu can negatively affect the CNS and promote MS pathogenesis due in part to the increased blood-brain barrier permeability by the actions of adipose tissue-derived cytokines or adipokines. By crossing the blood-brain barrier, the pro-inflammatory adipokines such as leptin, resistin, and visfatin activate the CNS-resident immune cells, and promote the inflammatory responses; subsequently, demyelinating lesions occur in the white matter of the brain and spinal cord. Therefore, better knowledge of the adipokines' role in the induction of obesity-related chronic inflammation and subsequent events leading to the dysfunctional blood-brain barrier is essential. In this review, recent evidence regarding the possible roles of obesity and its related systemic low-grade inflammation, and the roles of adipokines and their genetic variants in the modulation of immune responses and altered blood-brain barrier permeability in MS patients, has been elucidated. Besides, the results of the current studies regarding the potential use of adipokines in predicting MS disease severity and response to treatment have been explored.

PyProtModel: An easy to use GUI for comparative protein modeling.

A deep insight into the 3D structures of the proteins is essential to understand their functions and will be helpful in drug design and making decisions for the treatment of diseases. The 3D structure for less than one-thousandth of the protein sequences has been determined so far due to the slow structure elucidation procedures with experimental methods, such as X-ray. For this reason, different computational methods were used to determine the structure of the proteins, including template-based and de novo approaches. Much software has been developed to facilitate the computational approaches in protein modeling, some of which need user expertise and extensive knowledge in bioinformatics. The present study attempted to provide a user-friendly environment to motivate the researchers in computational biology, a Python-based interface based on MODELLER software. PyProtModel can be used as a toolbox in structural bioinformatics for protein modeling from sequence to the prediction of 3D structure. In addition, the users can take benefits of PyProtModel in order to prepare and evaluate protein PDB files prior to other in silico experiments. PyProtModel allows the user to apply different MODELLER options, automates, and speeds up time-consuming homology modeling steps. Different aspects of PyProtModel and a comprehensive view of the application will be discussed in this paper. The application is available for download and use at: https://github.com/msisakht/pyprotmodel.git.

Correlation between IL-28 polymorphism and spontaneous clearance in HCV patients: systematic review and meta-analysis.

Hepatitis C virus (HCV) is a serious global health issue. Nearly 20% of HCV patients spontaneously clear the virus. While some studies have shown an association of spontaneous clearance (SC) of the virus with interleukin (IL) 28B single-nucleotide polymorphisms (SNPs), others did not show such a relationship. Thus, the purpose of the present study was to investigate the association of IL28B polymorphisms (12979860 SNP) with SC of HCV infection. Upon initial screening of the databases, a total of 545 articles were retrieved, of which 22 studies that met predefined eligibility criteria were entered into the meta-analysis. Odds ratios (ORs) with confidence intervals (95% CI), heterogeneity, publication bias, and sensitivity analysis were assessed. According to the meta-analysis results, a significant association was observed between the rs12979860 SNP and SC of HCV infection. The results indicated that the ORs of SC from hepatitis C virus infection were 2.75 times higher in those with cytokine gene polymorphisms (95% CI, 2.23 to 3.38). Moreover, it was found that the prevalence of rs12979860 CC was 0.33 with 95 CI 0.28-0.38 in genotype 1 and was 0.40 with 95 CI 0.34-0.47 in other genotypes. Our meta-analysis results suggest that IL28B rs12979860 CC is a strong predictor for SC of hepatitis C infection in PEG IFN-a/RBV-treated patients.

Proportion of T follicular helper cells in peripheral blood of rheumatoid arthritis patients: a systematic review and meta-analysis.

Introduction:Alterations in the levels and activity of Tfh may lead to impaired immune tolerance and autoimmune diseases. The aim of this study was to investigate the proportion and types of Tfh cells in the peripheral blood (PB) of RA patients.Areas covered:Comprehensive databases were searched for studies evaluating the proportion of Tfh cells in the PB of patients with RA compared to healthy control (HCs).The proportion of Tfh cells in RA patients was significantly higher than in HCs (SMD 0.699, [0.513, 0.884], p < 0.0001). Furthermore, Tfh cells proportion in untreated-RA and early-RA patients was markedly greater than HCs, when comparisons done without considering the definition markers, and also when Tfh cells were defined by the specified definition markers. While the proportion of Tfh cells by all definitions was higher in active-RA compared to HCs, analysis of two definitions, CD4+CXCR5+ and CD4+CXCR5+ICOS+, didn't show significant differences. Furthermore, higher proportion of Tfh cells defined by all definitions and a specified definition (CD4+CXCR5+PD-1high) was observed when S+RA compared to S-RA patients.Expert opinion:The results demonstrate that circulating Tfh are highly elevated in RA patients highlights its potential use as a biomarker and a target for RA therapy.

The prevalence of stunting among children and adolescents living in the Middle East and North Africa region (MENA): A systematic review and meta-analysis.

BACKGROUND: Given the strategic importance of the MENA, the state of war and inequity in the region and its effect on malnutrition which leads to mortality and reduced economic development in this region, the current study purposed to examine the prevalence of stunting as an indicator of chronic malnutrition in the MENA region, with consideration given HDI, rural/urban area, and war-involved countries. METHODS: The electronic databases of PubMed, SCOPUS, Web of science, and Embase were systematically searched, and English-language articles published between January 1, 2009 and December 31, 2019 were included in this study. The POLIS (population, outcome, location, indicator, study design) criteria were used to perform the systematic review, and studies involving children 2 to 18 years of age were selected. RESULTS: Fifty-eight (n = 2 202 869) were included based on the study's inclusion criteria. The prevalence of stunting in children in the total MENA region was 22.0% (95% confidence interval (CI) = 20.4-23.6; I2 = 99.92%, P < 0.0001). The studies included in the meta-analysis were analyzed by subgroups. The pooled prevalence of stunting in children aged 2-5 years old and children aged 6 and older was 25.7% and 16.5%, respectively. The pooled prevalence of stunting was 34.1% in rural and 12.4% in urban areas. The pooled prevalence of stunting according to HDI was 30.1%, 28.5%, 13.1%, in low, medium, and high HDI countries, respectively. Furthermore, the pooled prevalence of stunting according to war status was 28.5% in war-involved countries vs 20.6% in others. CONCLUSIONS: High prevalence of malnutrition was seen based on stunting indicator in the meta-analysis study in the MENA region, and this issue became more pronounced when the data was divided into subgroups based on age, residential area, and HDI. Inequality regarding social, economic, and political factors leads to significant malnutrition in the mentioned region.

IL-18 in Blood Serum of Hepatitis C Patients Might be of Predictive Value for Individual Outcomes.

OBJECTIVE: Pro- inflammatory cytokines including Interleukin (IL)-18 have been shown to be involved in the clearance of Hepatitis C virus (HCV) infection. However, changes in the balance of pro- and anti-inflammatory cytokines production during the immune response, can elicit a variety of liver damages. Therefore, it is of interest to study IL-18 serum levels in hepatitis patients and its correlation with HCV infection. METHODS: Twenty-nine newly diagnosed HCV+ patients with no history of antiviral therapy, and 17 healthy controls, were enrolled in our study. Biochemical markers of liver disease were evaluated by biochemistry assay kits. Serum concentrations of IL-18 were determined with the ELISA method before and after treatment with pangenotypic direct-acting antivirals (DAAs) treatment. RESULTS: Our results showed statistically significant difference in serum levels of IL-18 in HCV+ patients (692.261 ± 48.76) compared to healthy controls (520.00 ± 44.73) (P=0.021). However, there was no significant difference in IL-18 serum levels between the treated group compared to untreated patients (P=0.74). No significant correlations were detected between the level of IL-18 and liver enzyme levels. CONCLUSION: According to our study, IL-18 might be a disease marker associated with HCV infection; however, this conclusion requires further investigation.

Withdrawal Notice: EnzyPha, an Engineered Helper Phage Developed to Overcome Most of the Limitations Regarding Filamentous Phage Titration and ELISA Tests

The article has been withdrawn at the request of the authors of the journal Protein & Peptide Letters. Bentham Science apologizes to the readers of the journal for any inconvenience this may have caused. The Bentham Editorial Policy on Article Withdrawal can be found at https://benthamscience.com/editorial-policiesmain. php. BENTHAM SCIENCE DISCLAIMER: It is a condition of publication that manuscripts submitted to this journal have not been published and will not be simultaneously submitted or published elsewhere. Furthermore, any data, illustration, structure or table that has been published elsewhere must be reported, and copyright permission for reproduction must be obtained. Plagiarism is strictly forbidden, and by submitting the article for publication the authors agree that the publishers have the legal right to take appropriate action against the authors, if plagiarism or fabricated information is discovered. By submitting a manuscript, the authors agree that the copyright of their article is transferred to the publishers if and when the article is accepted for publication.

In Vitro Effects of Sodium Benzoate on the Expression of T Cells-related Cytokines and Transcription Factors in Adjuvant-induced Arthritis Model.

Though the exact etiology of rheumatoid arthritis (RA) is unknown, the contribution of immune cells in the disease process is completely acknowledged. T helper (Th) 1 and Th17-related cytokines are required for the disease development and progression, while Th2 and regulatory T cells (Tregs)-derived cytokines are protective. Studies have shown that sodium benzoate (NaB) can switch the balance of Th cell subsets toward Th2 and Tregs. The present study aimed to evaluate the possible effects of NaB on the expression of CD4+T cells-related cytokines and transcription factors in splenocytes derived from an animal model of RA, adjuvant-induced arthritis (AIA). AIA was induced in rats by injection of Freund's adjuvant containing mycobacterial antigens (Mtb). Splenocytes were isolated from AIA rats and restimulated ex vivo with Mtb in the presence or absence of NaB for 24 h. To determine the effects of NaB on the expression of T cells-related cytokine and transcription factor genes, real-time PCR was performed. NaB treatment of Mtb-stimulated splenocytes derived from arthritic rats resulted in significant increases in the gene expressions of Tregs-related cytokines (IL-10 and TGF-ß) and Foxp3 transcription factor, and significant decreases in the expression of Th1-related cytokines (TNF-α and IFN-γ) and the T-bet transcription factor. The ratios of Th1/Th2 (IFN-γ/IL-4), Th1/Treg (IFN-γ/TGF-ß and IFN-γ/IL-10) and Th17/Treg (IL-17/IL-10 and IL-17/IL-10+TGF-ß)-related cytokines were also significantly decreased. In conclusion, NaB can potentially be considered as a useful therapeutic agent for the treatment of RA and other Th1 and Th17-mediated diseases.

Designing a multi-epitope vaccine against blood-stage of Plasmodium falciparum by in silico approaches.

Plasmodium falciparum causes the most severe form of malaria disease and is the major cause of infection-related mortalities in the world. Due to increasing in P. falciparum resistance to the first-line antimalarial drugs, an effective vaccine for the control and elimination of malaria infection is urgent. Because the pathogenesis of malaria disease results from blood-stage infection, and all of the symptoms and clinical illness of malaria occur during this stage, there is a strong rationale to develop vaccine against this stage. In the present study, different structural-vaccinology and immuno informatics tools were applied to design an effective antibody-inducing multi-epitope vaccine against the blood-stage of P. falciparum. The designed multi-epitope vaccine was composed of three main parts including B cell epitopes, T helper (Th) cell epitopes, and two adjuvant motives (HP91 and RS09), which were linked to each other via proper linkers. B cell and T cell epitopes were derived from four protective antigens expressed on the surface of merozoites, which are critical to invade the erythrocytes. HP91 and RS09 adjuvants and Th cell epitopes were used to induce, enhance and direct the best form of humoral immune-response against P. falciparum surface merozoite antigens. The vaccine construct was modeled, and after model quality evaluation and refinement by different software, the high-quality 3D-structure model of the vaccine was achieved. Analysis of immunological and physicochemical features of the vaccine showed acceptable results. We believe that this multi-epitope vaccine can be effective for preventing malaria disease caused by P. falciparum.

Application of molecular dynamics simulations to design a dual-purpose oligopeptide linker sequence for fusion proteins.

Proteins are often monitored by combining a fluorescent polypeptide tag with the target protein. However, due to the high molecular weight and immunogenicity of such tags, they are not suitable choices for combining with fusion proteins such as immunotoxins. In this study, we designed a polypeptide sequence with a dual role (it acts as both a linker and a fluorescent probe) to use with fusion proteins. Two common fluorescent tag sequences based on tetracysteine were compared to a commonly used rigid linker as well as our proposed dual-purpose sequence. Computational investigations showed that the dual-purpose sequence was structurally stable and may be a good choice to use as both a linker and a fluorescence marker between two moieties in a fusion protein.

Anti-ROR1 scFv-EndoG as a Novel Anti-Cancer Therapeutic Drug

Aim: Immunotoxins are proteins that consist of an antibody fragment linked to a toxin, used as agents for targeted therapy of cancers. Although the most potent immunotoxins are made from bacterial and plant toxins, obstacles which contribute to poor responses are immunogenicity in patients and rapid development of neutralizing antibodies. In the present study we proposed a new therapeutic immunotoxin for targeted cancer therapy of ROR1 expressing cancers: an anti ROR1 single chain fragment variable antibody (scFv)-endonuclease G (anti ROR1 scFv-EndoG). Methods: The three-dimensional structure of anti ROR1 scFv-EndoG protein was modeled and structure validation tools were employed to confirm the accuracy and reliability of the developed model. In addition, stability and integrity of the model were assessed by molecular dynamic (MD) simulation. Results: All results suggested the protein model to be acceptable and of good quality. Conclusions: Anti-ROR1 scFv-EndoG would be expected to bind to the ROR1 extracellular domain by its scFv portion and selectively deliver non-immunogenic human endonuclease G enzyme as an end-stage apoptosis molecule into ROR1-expressing cancer cells and lead rapidly to apoptosis. We believe that anti ROR1 and other anti-tumor antigen scFv-EndoG forms may be helpful for cancer therapy.

ScFv Improvement Approaches.

The most common recombinant antibody format is the single chain fragment variable (scFv) which it contains the complete antigen-binding domains of an intact antibody. ScFv fragments have found vast medical and non-medical applications. Several approaches have been employed to increase the affinity, avidity and structural stability related to these antibody fragments. Most approaches related to scFv improvement have been included in this review.