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  Background : Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by selective destruction of pancreatic beta cells.   Methods: The study included 80 children, 20 of them have T1DM, 40 children were selected from first degree relatives to the same child and 20 healthy children serve as control. Body mass index (BMI) was calculated, random blood glucose and glycosylated hemoglobin A1c (GHbA1c) were measured. The following biochemical markers were measured in sera of all subjects by ELISA kits: Human insulin ,C-peptide, human islet cell antibody (ICA), insulin auto antibodies (IAA) and antiglutamic acid decarboxylase (anti-GAD) antibodies. Results : This study showed that diabetic children had high level of ICA (65%), IAA (55%), anti-GAD antibodies (50%) and decrease in C-peptide (60%). Whereas the relatives showed high level of anti-GAD antibodies (30%), IAA(25%), ICA(2.5) and decrease in C-peptide (30%). Anti-GAD antibodies were significantly higher among the relatives of the diabetics compared to the healthy controls. Conclusions : The strongest predictors of diabetes were C- peptide and islets cell antibodies, which had odd ratio 4.7 and 3.1, respectively. Autoantibodies could distinguish T1DM patients from healthy control subjects and they may also identify individuals at high risk during progression from pre-diabetes to overt disease.

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Background: Hepatitis B infection is a major public health problem worldwide. Given that immune response towards the vaccine is not perfect, we aimed to evaluate circumstances of immune response in vaccinated students.
Materials and Methods: In this study, 219 medical students of Ardabil University of Medical Sciences were recruited, who had been administered vaccine series for the first time, and booster doses after one and six months completely. The serum samples were extracted from whole blood of the participants. The concentration of Hepatitis B surface antigen (HBsAg) and anti-HBs antibody (HBsAb) was measured using a commercial ELISA kit.
Results: It was observed that 201 cases (91.8%) out of 219 cases had positive anti-HBs antibody response, and 18 subjects (8.2%) were nonresponsive cases. Level of HBsAb was significantly different between males and females as well as alcoholics and non-alcoholics. None of the cases was identified as positive for HBsAg.
Conclusion: Considering the results of the present and previous studies in other countries, it can be claimed that the mass vaccination has been effective, especially in medical students.

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Regarding the importance of inhibiting VEGF and unique features of VHHs as a new generation of antibody-based therapeutics, the present study aimed to generate VHHs against the receptor binding domain of VEGF, thereby blocking of VEGF binding to its receptor. After preparing the gene repertoire of VHH fragments from an immunized camel, a VHH phage display library was constructed. We adopted a stringent successive biopanning to isolate the phages displaying VHH with high affinity to VEGF-RBD.A significant enrichment of phages that specifically bound to the target protein was obtained after six rounds of panning. Of the specific clones with high binding affinity screened by monoclonal phage ELISA, 52% shared the same VHH sequence, showing its high enrichment. Using molecular simulation of antigen-antibody interaction based on the crystallographic information of VEGF/VEGFR2, molecular dynamics simulations and MM/PBSA free energy calculations, we provide a reliable picture of the binding site of antibody on antigen. The key residues in the VEvhh1-VEGF interface were dissected and the energetics was analyzed by MM/PBSA. The results of studies revealed that VEvhh1 binds to the receptor binding site of VEGF with high binding energy and showed the highest affinity to the residues of VEGF which are responsible for VEGF binding to VEGFR2. Also the antibody potently covers these key functional residues of VEGF, thereby inhibiting VEGF binding to its receptor and probably abrogating its biological activity. This study may represent VEvhh1 as an anti-VEGF and anti-angiogenic candidate.

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Cucumber mosaic virus (CMV) is one of widely-spread viruses of plants with the broadest host range encompassing over 1200 species. One major limiting factor for detection of the virus is unavailability of the virus-specific antibodies especially in developing countries. Recombinant DNA technology facilitates antibody preparation without requiring special equipment. In this study, coat protein (CP) gene cDNA of CMV was subcloned from pTZ57CMVCP into pET21a expression vector and transformed into Escherichia coli strain Rosetta. Expression of CMV CP was examined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and its identity was confirmed by western blotting, dot blot immunobinding assay (DIBA) and enzyme- linked immunosorbent assay (ELISA) using anti- CMV antibody. The expressed protein was purified using T7•Tag affinity purification kit and used as antigen for raising polyclonal antibodies in two mice. The purified anti-CMV CP IgG and the conjugated IgG performed favourably in terms of specificity and sensitivity to detect both expressed CP (antigen) and CMV isolates in infected cucurbit plants using plate trapped antigen (PTA)- ELISA, double-antibody sandwich (DAS)-ELISA and western blotting. The prepared antibodies can be applied in serological and sero-molecular tests in studies on the virus and in screening of plants for the infection. This is the first report of preparation of antibodies against CP of an indigenous isolate of CMV.

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Two strains -425 and Y87/47- of Alfalfa mosaic virus (AMV) were propagated in and purified from Nicotiana tabacum cv. Samsun NN. Thirty-three AMV specific monoclonal antibodies (MAbs) from two fusions were raised against strain 425. These antibodies were of isotypes IgG1 and IgM. MAbs recognised three types of epitope. Group I did not react with the virus particle surface or viral coat protein of two strains in PTA-ELISA, but they reacted with a 30-kDa structural coat protein of AMV by immunoblot analysis only and were able to recognise cryptotopes. Group II reacted with metatopes of both strains in PTA-ELISA. Group III reacted with a 30-kDa structural coat protein of AMV by immunoblot analysis and in PTA-ELISA for the Y87/47 strain only. Immunoblocking experiments in which suspensions of purified AMV and MAb were offered between parafilm membranes for acquisition by Myzus persicae revealed that MAb-2 was effective in blocking (inhibiting) transmission. This result suggests that the epitope which was localised by MAb-2 plays a role in the aphid transmission of AMV.

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Newcastle disease is a fatal viral disease which is highly contagious that affects most species of birds and is a major economic threat in the poultry industry. Both the HN and F glycoproteins of Newcastle disease virus (NDV) are essential for pathogenicity and virus infectivity. This study describes immunization of DNA vaccines encoding the HN, F or both the genes of New castle disease virus. In our previous study, the antigen expression of the insert genes has been validated in vitro by Western Blotting and Indirect Immunosenest. In this study, ELISA and HI analysis of the in vivo experiment on SPF (specific Pathogen Free) chickens showed the induction of humoral responses by the DNA vaccines. Our finding indicated that twice vaccination with pDNA was able to elicit significant antibody titers (P< 0.05) by either monocistronic (pIRES/HN and pIRES/F) or bicistronic (pIRES/F/HN) plasmid, after one week of second pDNA vaccination (booster). The results proposed that DNA immunization of chickens at second vaccination had enhanced the antibody response successfully. Also, it revealed that vaccination with the co-expression plasmid pIRES/HN/F can induce a stronger antibody response than vaccination with pIRES/HN or pIRES/F alone.

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The legume crops such as chickpea and lentils are mainly cultivated in semi-arid tropical lands. Chickpea chlorotic dwarf virus (CpCDV) causes major losses to legumes throughout the world. Producing of specific antibody against this virus is crucial for surveys of disease in the fields and assessment of vial resistance in plant cultivars. Present article describes developing of specific antibody against the CpCDV virus by applying recombinant protein. In this study, coat protein of CpCDV was selected as a target for detection and preparation of polyclonal antibody. To achieve this aim CP gene encoding coat protein of CpCDV was initially PCR-amplified and inserted into bacterial expression vector. Expression of recombinant protein was performed in Bl21 strain of Escherichia coli. Purification was carried out under native conditions and the accuracy of recombinant protein production was confirmed by electrophoresis. The purified recombinant coat protein of CpCDV was used for immunization of rabbit. Purification of immunoglobulin molecules was performed by affinity chromatography using protein A column followed by conjugating of IgG to alkaline phosphatase enzyme. The capability of purified antibodies and conjugates for efficient detection of infected plants was assessed by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), western blotting and dot immunosorbent assay (DIBA). These results proved that prepared IgG and conjugate are able to distinguish with high efficiency CpCDV infected plants. To the best of our knowledge, this is the first report for production of anti-CpCDV antibodies raised through recombinant protein technology.

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Backgrounds: SARS-COV-2 infection is not always correlated with protection. Antibody seroprevalence in unvaccinated individuals, which is usually measured by N-specific antibodies, is not necessarily correlated with protection, while antibodies against S protein show a better correlation with protection due to its neutralizing epitopes. In this study, we tried to improve our conception of the hidden perspective of SARS-COV-2 in epidemiological reports and investigate anti-S antibody prevalence among anti-N antibody-positive asymptomatic and mildly symptomatic patients.
Materials & Methods: Blood samples were collected from asymptomatic or mildly symptomatic volunteer participants and symptomatic hospitalized patients with negative PCR results from May 30 to June 17, 2020. Detection of SARS-COV-2 antibodies was done using an ELISA kit targeting N or S protein.
Findings: Totally, 716 samples from volunteer participants and 81 samples from symptomatic hospitalized patients with negative PCR results were evaluated. The test performance-adjusted seroprevalence (95% CI) of SARS-COV-2 antibody was 17.3% (8.8-25.8%) for anti-N IgG in volunteers and 25.5% (12.8-39.7%) for anti-N and anti-S IgM in hospitalized patients. Among anti-N IgG positive infected individuals, 49.2% (21.4 and 78.8%) were anti-S antibody positive.
Conclusion: The results showed that SARS-COV-2 infection sometimes occurs in individuals without symptoms or with mild symptoms, but in more than half of them, the produced antibody is not protective. The findings of hospitalized patients showed that the combination of IgM assay with real-time PCR improved the disease diagnosis by more than 25% in cases with negative molecular test results.

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Objective: Pseudomonas aeruginosa is the major cause of septicemia and wound infection in burned patients. Immunotraphy is the best practical way for prevention and treatment of these infections. Flagella as one of the most important bacterial virulence factors has important role in attachment, motility, chemotaxis and TLR-5-dependent immune response so that it propounded as a vaccine candidate. Production of anti-flagellar antibodies and evaluation of its protective effects in burned induced infection of mice was the main aim of this study. Materials and Methods: In the first step, flagellar antigen prepared by ultra-centrifugation. Anti-flagellar antibodies produced in rabbit and its impurity separated by absorption technique. Specification of the obtained antibodies for flagellar antigen was investigated via agglutination test. After determination of LD50 in a known strain, different dilutions of anti-flagellar antibodies injected in burned mice for passive immunization. The rate of bacterial spread from burn site was determined by quantification assay of bacteria in skin and liver. In this study, clinical isolate and PA103 in addition to ATCC 27853 strain were used for agglutination test. Results: H-antiserum reduced mortality of burned mice challenged with ATCC 27853 strains about 80%. Counting of bacteria in the skin and liver showed that the number of bacteria in immunized mice, in contrast with control group, was significantly low. Conclusion: The results of this study showed that anti-flagellar antibodies of Pseudomonas can inhibit invasion of Pseudomonas and facilitate its opsonization, so these antibodies have protective effects in burned wound infections.

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Aptamers or chemical antibodies are mostly nucleic acid sequences that can bind to various diverse targets including small molecules, large molecules, and cells. Among the advantages of aptamers compared to antibodies, we can mention the in vitro production process, the possibility of choosing aptamers against toxic and non-immunogenic molecules, long-term storage, and much lower production costs. Aptamers can also be easily modified or stabilized, and their synthesis is associated with high purity and reproducibility, they are chemically stable, and due to their  nucleic acid structure, they are much more flexible than antibodies, and they can be used in the form of molecular beacons probes, a combination of use aptamer-target interaction and nucleic acid amplification to achieve highly sensitive detection ranges. These interesting features have made aptamers ideal diagnostic elements for analytical tools such as biosensors, colorimetric methods, surface plasmon resonance, and lab-on-a-chip. However, all these methods require skilled workers and laboratory-based instruments, thus limiting their application. In this regard, lateral flow assay or paper strip kits provide fast and reliable results and only require user intervention in the sample addition phase. Due to their simplicity is widely used in various fields including medicine, food product quality inspection, and environmental safety. In this work, while introducing aptamers, , an overview of its unique application in lateral flow assay and the future of this technology should be studies.
 

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In recent years, targeted drug delivery systems have emerged as a promising approach to increase the efficacy and minimize side effects of therapeutic agents. Cerasomes are a special type of liposomes with covalent siloxane networks on the surface that provide exceptional morphological stability while retaining all the beneficial properties of liposomes. Cerosomes provide a unique platform for drug encapsulation and delivery due to their biocompatibility, stability, controllable release, and long-term storage. In this research, an attempt has been made to engineer the surface of cerosomes to increase the selectivity and efficiency of drug delivery. In such a way that the Herceptin antibody is placed on the surface of the serosa and allows the precise targeting of HER²⁺ cells. Then, the physicochemical characteristics of antibody-functionalized cerosomes, including size and surface charge 229±15.6 nm and 13.5±1.2 mV were respectively obtained. The results of IR and fluorescence spectrum showed that the antibody was successfully attached to the surface of cerasome with a binding efficiency of 64%. These results prove the basic mechanisms governing the synthesis of immunocerasomes and provide a valuable approach for future developments in targeted drug delivery systems.
 

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Objective: The study of physiological changes in recombinant cell lines provides useful information to improve production performance. In this study, we investigate the effects of an anti-CD33 chimeric IgG₄ expression on Sp2.0 cell growth. Methods: Variable region genes of light and heavy chains of monoclonal antibody produced by M195 were cloned in pFUSE-CLIg-hk and pFUSE-CHIg-hG4 expression vectors, respectively. Transfection of recombinant plasmids into Sp2.0 cell lines was performed using lipofectamine in two steps. Positive transformant cells were isolated and subjected to PCR, RT-PCR and Western blot analysis to confirm the integration of gene cassettes and the expression of recombinant IgG₄. To assess the growth parameters, recombinant and parent Sp2.0 cell lines were seeded at a density of 1×10⁵ cells/ml in duplicate into 12-well plates. For nine days, culture plates were sampled daily and viable cell count and viability determined. Results: The results of PCR, RT-PCR and Western blot analyses confirmed the generation of stable producer cell lines. In recombinant cells, the maximum cell density decreased by 46%. However, it was observed that IgG₄ expression had no effect on cell viability of these transfectants. Conclusion: Our results showed that the expression of recombinant IgG₄ can change growth parameters in Sp2.0 cell lines that express the pFUSE-CHIg-hG4-pFUSE-CLIg-hk construct.

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Objectives: CtxB (Cholera toxin B subunit) contributes to a vaccine's efficacy by stimulating production of the anti-CtxB antibody. Various attempts have been made to increase production of this antibody. Chitosan is a mucoadhesive polysaccharide that has tremendous potential for oral vaccine delivery in terms of its exclusive features that include biocompatibility, biodegradability, high charge density and non-toxicity. We investigated the potential for chitosan nano­fibers and nanocapsules as novel carrier systems for the oral delivery of CtxB. Methods: Antigen-containing chitosan nanofibers were prepared by electrospinning a chitosan/AcOH solution. Encapsulation of the antigen inside the chitosan nanofibers was confirmed through infrared spectroscopy analysis (FTIR). Guinea pigs were immunized with free antigen and CtxB antigen or antigen alone by direct administration of antigen-containing chitosan nanofibers into the buccal cavity. Serum immunoglobulin G (IgG) and intestinal immunoglobulin A (IgA) antibody responses were determined Results: The results indicated that antigen in the chitosan nanofibers or nanocapsules elicited very high IgA and IgG responses. No detectable IgA and IgG responses were obtained after oral immuniza­tion with CtxB. The results of the antibody titer were analyzed using the ANOVA and LSD tests. Conclusion: CtxB inside the nanofiber increased antibody production when administered orally. This system might be used for delivery of other antigens.

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Objective: This study attempted to generate monospecific antibodies through immunization with recombinant proteins and subsequent purification by synthetic peptides (the PrIPeP model).

Methods: The SRY gene was cloned on a pet-28a vector and the recombinant protein was expressed in the Escherichia coli (E.coli) BL21 strain. The purified antigen was emulsified in Freund’s adjuvant and injected into rabbits according to a standard time table. Then, a specific peptide was designed, synthesized, and conjugated to sepharose 4B to generate an affinity purification column. As a control, the peptide was conjugated to KLH and used for immunization, as above. Antisera against the conjugated peptide (Pep-antisera) and SRY recombinant protein (Pro-antisera) were evaluated by ELISA and subsequently subjected to the affinity purification column. Sensitivity and specificity of the purified antibodies against SRY recombinant protein as well as negative controls (recombinant HSFY, RBMY, and RPSFY) were assessed by Western blot analysis.

Results: Titration by ELISA confirmed proper immunization and specificity of both antigens. Western blot analysis validated the specificity and sensitivity of the IgG class purified antibodies.

Conclusion: By applying the PrIPeP model, it is possible to develop antibodies against the native structure of a protein whilst avoiding challenges of peptide-carrier protein conjugation.

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SARS-COV-2, the latest member of Coronaviridea family as the cause of the recent global epidemic, has inflicted sever damages in different fields on most governments. Appropriate strategies such as identifying infected individuals and isolating them, trying to produce an effective vaccine, finding efficient treatment and making correct decisions in the social, economic and health fields are the current priorities of the world. Serological tests provide useful information in all of the above areas. In this article we will discuss the importance of performing SARS-COV-2 serological tests in diagnosis, vaccination, treatment and proper planning in the society.

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The new coronavirus was firstly identified in the late December 2019 that causes severe respiratory and other organ complications in Covid-19 patients. Although many attempts have been employed to introduce and provide effective medications against this infection, there is still no definitive treatment for the infection. However some agents have shown promising effects in patients and some others are in preliminary or clinical studies. Monoclonal antibodies are of great interest in the treatment of Covid-19, but despite the fact that more than 120 clinical trials have been performed or are being completed; only tocilizumab has shown promising results and is sometimes used in therapeutic protocols. In this review, therapeutic monoclonal antibodies against Covid-19 that are currently in phase 3 or higher clinical trial have been discussed.

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SARS-COV-2, the latest member of Coronaviridea family as the cause of the recent global epidemic, has inflicted sever damages in different fields on most governments. Appropriate strategies such as identifying infected individuals and isolating them, trying to produce an effective vaccine, finding efficient treatment and making correct decisions in the social, economic and health fields are the current priorities of the world. Serological tests provide useful information in all of the above areas. In this article we will discuss the importance of performing SARS-COV-2 serological tests in diagnosis, vaccination, treatment and proper planning in the society.

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