Recombinant Multiepitope Protein Research Articles

Development of recombinant proteins for vaccine candidates against serotypes O and A of Foot-and-Mouth Disease virus in Bangladesh.

Frequent vaccine failure leading to recurrent outbreaks of Foot-and-Mouth Disease (FMD) in livestock populations necessitates the development of a customizable vaccine platform comprising potential antigenic determinants of circulating lineages of FMD viruses. Artificially designed, chimaeric protein-based recombinant vaccines are novel approaches to combat the phylogenetically diverse FMD Virus (FMDV) strains. Among seven recognized serotypes, only serotypes O and A are dominantly circulating in Bangladesh and neighbouring countries of Asia, where transboundary transmission, recurrent outbreaks and emergence of novel lineages of FMDV are highly prevalent. The objective of this study was to develop multi-epitope recombinant proteins, procuring immunogenicity against circulating diverse genotypes of FMDV serotypes O and A. Two chimaeric proteins, named B1 (41.0 kDa) and B3 (39.3 kDa), have been designed to incorporate potential B-cell and T-cell epitopes selected from multiple FMDV strains, including previously reported and newly emerged sub-lineages. After expression, characterization and immunization of guinea pigs with a considerable antigen load of B1 and B3 followed by serological assays revealed the significant protective immunogenicity, developed from the higher (100 µg) doses of both antigens, against most of the currently prevalent serotype O and A strains of FMDV. The efficient expression, antigenic stability, and multivalent immunogenic potency of the chimaeric proteins strongly indicate their credibility as novel vaccine candidates for existing serotypes O and A of FMDV in Bangladesh and surrounding territories.

Designing a Novel Multi-epitope Peptide as a Potential Serodiagnosis Marker for the Diagnosis of Acinetobacter baumannii: An In silico Approach

Background: Acinetobacter baumannii is an opportunistic pathogen that causes many infections, including nosocomial infections; this bacterium has a high mortality rate among other bacteria. A. baumannii has an elastic genome that changes rapidly when exposed to harsh environmental conditions, leading to widespread bacterial resistance to various disinfectants and antibiotics. The high ability of bacteria to bind to all surfaces and survive in different conditions has caused the spread of bacteria in various environments. Rapid detection is very important in preventing the spread and even treatment of the infection. Methods: Currently, the Polymerase Chain Reaction (PCR) method is the only effective method used for diagnosis, which has some pros and cons. Results and Conclusion: This study aimed to design a new recombinant multi-epitope protein from Acinetobacter baumannii that can be used in ELISA for rapid diagnosis. The unique feature of this study from others is the use of patient serum for antibody monitoring.

Humoral and cellular immunity in response to an in silico-designed multi-epitope recombinant protein of Theileria annulata.

Tropical theileriosis is a lymphoproliferative disease caused by Theileria annulata and is transmitted by Ixodid ticks of the genus Hyalomma. It causes significant losses in livestock, especially in exotic cattle. The existing methods for controlling it, chemotherapeutic agents and a vaccine based on an attenuated schizont stage parasite, have several limitations. A promising solution to control this disease is the use of molecular vaccines based on potential immunogenic proteins of T. annulata. For this purpose, we selected five antigenic sequences of T. annulata, i.e. SPAG-1, Tams, TaSP, spm2, and Ta9. These were subjected to epitope prediction for cytotoxic T lymphocytes, B-cells, and helper T lymphocytes. CTL and B-cell epitopes with a higher score whereas those of HTL with a lower score, were selected for the construct. A single protein was constructed using specific linkers and evaluated for high antigenicity and low allergenicity. The construct was acidic, hydrophobic, and thermostable in nature. Secondary and tertiary structures of this construct were drawn using the PSIPRED and RaptorX servers, respectively. A Ramachandran plot showed a high percentage of residues in this construct in favorable, allowed, and general regions. Molecular docking studies suggested that the complex was stable and our construct could potentially be a good candidate for immunization trials. Furthermore, we successfully cloned it into the pET-28a plasmid and transformed it into the BL21 strain. A restriction analysis was performed to confirm the transformation of our plasmid. After expression and purification, recombinant protein of 49 kDa was confirmed by western blotting. An ELISA detected increased specific antibody levels in the sera of the immunized animals compared with the control group, and flow cytometric analysis showed a stronger cell-mediated immune response. We believe our multi-epitope recombinant protein has the potential for the large-scale application for disease prevention globally in the bovine population. This study will act as a model for similar parasitic challenges.

Evaluation of the humoral and mucosal immune response of a multiepitope vaccine against COVID-19 in pigs.

This study evaluated the immune response to a multiepitope recombinant chimeric protein (CHIVAX) containing B- and T-cell epitopes of the SARS-CoV-2 spike's receptor binding domain (RBD) in a translational porcine model for pre-clinical studies. We generated a multiepitope recombinant protein engineered to include six coding conserved epitopes from the RBD domain of the SARS-CoV-2 S protein. Pigs were divided into groups and immunized with different doses of the protein, with serum samples collected over time to determine antibody responses by indirect ELISA and antibody titration. Peptide recognition was also analyzed by Western blotting. A surrogate neutralization assay with recombinant ACE2 and RBDs was performed. Intranasal doses of the immunogen were also prepared and tested on Vietnamese minipigs. When the immunogen was administered subcutaneously, it induced specific IgG antibodies in pigs, and higher doses correlated with higher antibody levels. Antibodies from immunized pigs recognized individual peptides in the multiepitope vaccine and inhibited RBD-ACE2 binding for five variants of concern (VOC). Comparative antigen delivery methods showed that both, subcutaneous and combined subcutaneous/intranasal approaches, induced specific IgG and IgA antibodies, with the subcutaneous approach having superior neutralizing activity. CHIVAX elicited systemic immunity, evidenced by specific IgG antibodies in the serum, and local mucosal immunity, indicated by IgA antibodies in saliva, nasal, and bronchoalveolar lavage secretions. Importantly, these antibodies demonstrated neutralizing activity against SARS-CoV-2 in vitro. The elicited antibodies recognized individual epitopes on the chimeric protein and demonstrated the capacity to block RBD-ACE2 binding of the ancestral SARS-CoV-2 strain and four VOCs. The findings provide proof of concept for using multiepitope recombinant antigens and a combined immunization protocol to induce a neutralizing immune response against SARS-CoV-2 in the pig translational model for preclinical studies.

Protective efficacy of multiepitope vaccines constructed from common antigens of Eimeria species in chickens

Clinical avian coccidiosis is typically caused by coinfection with several Eimeria species. Recombinant protein and DNA vaccines have shown promise in controlling coccidiosis. On this basis, DNA vaccines that encode multiple epitopes from different Eimeria species may provide broad protection against coinfections. In this study, we designed a fusion gene fragment, 14EGT, that contained concentrated T-cell epitopes from four common antigens of Eimeria species (14-3-3, elongation factor 2, glyceraldehyde-3-phosphate dehydrogenase, and transhydrogenase). The multiepitope DNA vaccine pVAX1-14EGT and recombinant protein vaccine pET-32a-14EGT (r14EGT) were then created based on the 14EGT fragment. Subsequently, cellular and humoral immune responses were measured in vaccinated chickens. Vaccination-challenge trials were also conducted, where the birds were vaccinated with the 14EGT preparations and later exposed to single or multiple Eimeria species to evaluate the protective efficacy of the vaccines. According to the results, vaccination with 14EGT preparations effectively increased the proportions of CD4+ and CD8+ T cells and the levels of Th1 and Th2 hallmark cytokines. The levels of serum IgG antibodies were also significantly increased. Animal vaccination trials revealed alleviated enteric lesions, weight loss, and oocyst output compared to those of the control groups. The preparations were found to be moderately effective against single Eimeria species, with the anticoccidial index (ACI) ranging from 160 to 180. However, after challenge with multiple Eimeria species, the protection provided by the 14EGT preparations was not satisfactory, with ACI values of 142.18 and 146.41. Collectively, the results suggest that a multiepitope vaccine that encodes the T-cell epitopes of common antigens derived from Eimeria parasites could be a potential and effective strategy to control avian coccidiosis.

Evaluation of the Effectiveness of Polyclonal Antibody Developed against a Recombinant Multi-Epitope Protein Composed of Uropathogenic Escherichia coli Antigens

Evaluation of the Effectiveness of Polyclonal Antibody Developed against a Recombinant Multi-Epitope Protein Composed of Uropathogenic Escherichia coli Antigens

A Mini-Review on Potentials Proteins/Peptides Applied for Serodiagnosis of Human Monkeypox Infection and Future Trends.

In this mini-review, a search was conducted in the main databases for peptide and protein options that could be used in the development of serological diagnostic tests. Nine viable registres were found, and seven were selected (two patents and five studies). The main studies used the B21R peptide sequence as it is a high immunogenic epitope. In addition, studies on the improvement of these sequences were also found to avoid cross-reactions against other viruses of the same family, proposing a rational approach using multiepitope recombinant proteins. These approaches demonstrated high sensitivity and specificity values and are seen as viable options for developing new tests. New effective serological testing options, when combined with awareness, disease surveillance, early diagnosis, and rapid communication, form a set of key strategies used by health systems to control the spread of the monkeypox virus.

Identification of B-cell epitopes on structural proteins VP1 and VP2 of Senecavirus A and development of a multi-epitope recombinant protein vaccine

Senecavirus A (SVA) is an important pathogenic cause of vesicular disease in pigs worldwide. In this study, we screened the B-cell epitopes of SVA using a bioinformatics approach combined with an overlapping synthetic polypeptide method. Four dominant B-cell epitopes (at amino acid (aa) positions: 7–26, 48–74, 92–109, and 129–144) from the VP1 protein and five dominant B-cell epitopes (aa: 38–57, 145–160, 154–172, 193–208, 249–284) from the VP2 protein were identified. Multi-epitope genes comprising the identified B-cell epitope domains were synthesized, prokaryotic expressed, and purified, and their immune protection efficacy was evaluated in piglets. Our results showed that the multi-epitope recombinant protein rP2 induced higher neutralizing antibodies and provided 80% protection against homologous SVA challenge. Thus, the B-cell epitope peptides identified in this study are potential candidates for SVA vaccine development, and rP2 may offer safety and efficacy in controlling infectious SVA.

Proof of Concept of a Novel Multiepitope Recombinant Protein for the Serodiagnosis of Patients with Chagas Disease.

Chagas disease remains a neglected disease that is considered to be a public health problem. The early diagnosis of cases is important to improve the prognosis of infected patients and prevent transmission. Serological tests are the method of choice for diagnosis. However, two serological tests are currently recommended to confirm positive cases. In this sense, more sensitive and specific serological tests need to be developed to overcome these current diagnosis problems. This study aimed to develop a new recombinant multiepitope protein for the diagnosis of Chagas disease, hereafter named rTC. The rTC was constructed based on amino acid sequences from different combinations of Trypanosoma cruzi antigens in the same polypeptide and tested using an enzyme-linked immunosorbent assay (ELISA) to detect different types of Chagas disease. rTC was able to discriminate between indeterminate (IND) and cardiac (CARD) cases and cross-reactive diseases, as well as healthy samples, with 98.28% sensitivity and 96.67% specificity, respectively. These data suggest that rTC has the potential to be tested in future studies against a larger serological panel for the diagnosis of Chagas disease.

Expression and Purification of Recombinant Multi-epitope Protein of Rhipicephalus microplus Tick and its Antigenicity in Rabbits

Expression and Purification of Recombinant Multi-epitope Protein of Rhipicephalus microplus Tick and its Antigenicity in Rabbits

Designing a Recombinant Multi-epitope DNA Vaccine as Candidate for Protection against Pathogenic Leptospira Infection in Animals

Leptospirosis can cause severe disease and probable death in humans. Antigenic epitopes from pathogenic strains of the bacteria have shown potential for serving as vaccine candidates and play a key role in the sensitivity and specificity of immunodiagnostic tests. This in-vitro analysis was undertaken to develop a prototype recombinant DNA vaccine using in-silico epitope prediction method. Epitope prediction software programs predicted the most antigenic linear B-cell epitopes of OmpL1, LipL32, LipL41, Loa22, and LigA. Thirteen epitopes were predicted, connected by the Gly-Ser linker, and synthesized. The purity of the concentrated recombinant multi-epitope protein was assessed by restriction enzyme digestion and gel electrophoresis. In-vitro expression on mammalian Chinese Hamster Ovary cell line indicated strong cytoplasmic fluorescence produced based on an indirect immunofluorescence antibody test. The green color of the cytoplasm indicates successful transcribed and translated DNA as against the blue-stained nucleus observed in the un-transfected control group based on the indirect immunofluorescence antibody test. The findings of the current study showed high antibody binding potentials of the vaccine constructs, which could be used for diagnostic applications or as polyvalent vaccine candidates.

Efficacy of a Novel Multiepitope Vaccine Candidate against Foot-and-Mouth Disease Virus Serotype O and A.

Foot-and-mouth disease (FMD) is a highly contagious and economically devastating disease in cloven-hoofed animals. To prevent the spread of FMD virus (FMDV), traditional inactivated vaccines are used to immunize susceptible animals in disease-endemic countries. However, the inactivated FMD vaccine has several limitations, including safety concerns. To overcome these limitations, subunit proteins have been studied as alternative vaccine candidates. In this study, we designed two multiepitope recombinant proteins (OVM and AVM) containing antigenic sites (residue of VP1 132-162 and residue of VP1 192-212) of three topotypes of FMDV serotype O or three topotypes of FMDV serotype A. Each recombinant protein was efficiently expressed in Escherichia coli with high solubility, and the immunogenicity and protective efficacy of the proteins as FMD vaccine candidates were evaluated. The results showed that OVM and AVM emulsified with ISA201 adjuvant induced effective antigen-specific humoral and cell-mediated immune responses and successfully protected mice from O/Jincheon/SKR/2014, O/VET/2013, and A/Malaysia/97 viruses. In addition, intramuscular immunization of pigs with the OVM and AVM emulsified with ISA201 elicited effective levels of neutralizing antibodies to the viruses with homologous epitopes. Importantly, OVM-AVM emulsified with CAvant®SOE-X adjuvant conferred 100% protection against the O/Jincheon/SKR/2014 virus with homologous residues and 75% protection against A/SKR/GP/2018 with heterologous residues. The results presented in this study suggest that the combination of OVM and AVM protein with an effective adjuvant could yield an effective and safe vaccine candidate for the prevention and control of foot-and-mouth disease. In addition, our results provide a vaccine platform that can safely, cost-efficiently, and rapidly generate protective vaccine candidates against diverse FMDVs.

A novel multi-epitope recombinant protein elicits an antigen-specific CD8+ T cells response in Trypanosoma cruzi-infected mice

About 6.5 million people worldwide are afflicted by Chagas disease, which is caused by the protozoan parasite Trypanosoma cruzi. The development of a therapeutic vaccine to prevent the progression of Chagasic cardiomyopathy has been proposed as an alternative for antiparasitic chemotherapy. Bioinformatics tools can predict MHC class I CD8 + epitopes for inclusion in a single recombinant protein with the goal to develop a multivalent vaccine. We expressed a novel recombinant protein Tc24-C4.10E harboring ten nonameric CD8 + epitopes and using Tc24-C4 protein as scaffold to evaluate the therapeutic effect in acute T. cruzi infection. T. cruzi-infected mice were immunized with Tc24-C4.10E or Tc24-C4 in a 50-day model of acute infection. Tc24-C4.10E-treated mice showed a decreased parasitemia compared to the Tc24-C4 (non-adjuvant) immunized mice or control group. Moreover, Tc24-C4.10E induced a higher stimulation index of CD8 + T cells producing IFNγ and IL-4 cytokines. These results suggest that the addition of the MHC Class I epitopes to Tc24-C4 can synergize the antigen-specific cellular immune responses, providing proof-of-concept that this approach could lead to the development of a promising vaccine candidate for Chagas disease.

In silico designing of a recombinant multi-epitope antigen for leprosy diagnosis

BackgroundLeprosy is caused by Mycobacterium leprae and Mycobacterium lepromatosis. Most of the affected population lives in low-income countries and may take up to 10 years to show any clinical signs, which is how physicians diagnose it. However, due to progressive cell damage, early diagnosis is very important. The best way to confirm leprosy is through bacilloscopic, which only confirms the diagnosis and has low accuracy or PCR, that requires specialized operators and is expensive. Since the bacteria are fastidious and do not grow in any culture media, therefore, diagnosing leprosy in the lab is still a challenge. In this concern, a recombinant multi-epitope protein can be a beneficial strategy in the management of the diagnosis, as diverse immunogenic epitopes are precisely selected to detect specific antibodies. Therefore, the purposes of the present study were to select immunogenic epitopes from different relevant proteins, with immunogenic properties, and then to construct a recombinant multi-epitope protein that accuses the presence of the antibodies in the early stages of the disease, making it more than appropriate to be applied as a diagnostic tool. ResultsWe selected 22 common proteins from both species and, using bioinformatics tools, predicted B and T cell epitopes. After multiple filtering and analyzing, we ended up with 29 epitopes {MHC-I (total 18) and MHC-II (total 11)} from 10 proteins, which were then merged into one construct. Its secondary and tertiary structures were also predicted and refined to comprise the amino acid residues in the best conformation possible. The multi-epitope protein construct was stable, non-host homologous, non-allergic, non-toxic, and elicit humoral and cellular responses. It has conformational B cell epitopes and potential to elicit IFN-γ, IL-4, and IL-10 secretion. ConclusionsThis novel recombinant multi-epitope protein constructed using the common epitopes from M. leprae and M. lepromatosis has a huge immunological potential, is stable, and can be lyophilized to be used in ELISA plates or even in biosensors, which are user-friendly diagnosis tools, facilitating translation into human sample tests.

Preparation and characterization of a recombinant poly-epitopic vaccine EgG1Y162-2 (4) against cystic echinococcosis based on the linker GSGGSG

To perform prokaryotic expression and preliminary characterization of the recombinant poly-epitope vaccine EgG1Y162-2 (4) against cystic echinococcosis. The recombinant poly-epitope vaccine EgG1Y162-2 (4) against Echinococcus granulosus based on the linker GSGGSG was subjected to structural three-dimensional (3D) modeling using immunoinformatics to analyze the structural changes and evaluate the antigenicity of the vaccine. The pET30a-EgG1Y162-2 (4) recombinant plasmid was generated using double digestion with EcoR I and Sal I, and then transformed into competent cells. Following protein induction with isopropyl-β-D-thiogalactoside (IPTG), the prokaryotic expression proteins were characterized using Western blotting, and the antigenicity of the recombinant protein was analyzed using sera from cystic echinococcosis patients and health volunteers. The four EgG1Y162-2 proteins coupled by the 3D structure of the recombinant vaccine EgG1Y162-2 (4) presented independent and effective expression and good antigenicity. The highest protein expression was detected in the supernatant following induction of the recombinant plasmid pET30a-EgG1Y162-2 (4) by 0.2 mmol/L IPTG at 37 °C for 4 h, and a pure protein component was seen following elution with 60 mmol/L imidazole. Western blotting analysis of the recombinant multiepitope protein HIS-EgG1Y162-2 (4) showed a band at approximately 39 kDa, and this band was recognized by sera from cystic echinococcosis patients. A recombinant poly-epitope vaccine EgG1Y162-2 (4) against cystic echinococcosis has been successfully constructed, which provides a preliminary basis for researches on recombinant multi-epitope vaccine against cystic echinococcosis.

Rational Design and Evaluation of the Recombinant Multiepitope Protein for Serodiagnosis of Rubella.

Rubella is an infection caused by rubella virus (RV) and is generally regarded as a mild childhood disease. The disease continues to be of public health importance mainly because when the infection is acquired during early pregnancy, it often results in fetal abnormalities, which are classified as congenital rubella syndrome (CRS). An accurate diagnosis of rubella is thus of pivotal importance for proper treatment. The aim of the study was to produce a recombinant multiepitope protein (rMERUB) for the diagnosis of rubella, based on conserved immunodominant epitopes of glycoprotein E1 and E2. A synthetic gene was designed and cloned into vector pET21a with a 6xHis tag at the Cterminal for affinity purification and overexpressed in Escherichia coli cells. Biophysical analysis of rMERUB was performed by circular dichroism. Biological activity was assessed using an in-house ELISA assay. Expression in Escherichia coli showed a ~22 kDa protein that was purified and used to perform structural assays and an IgG ELISA. Structural analyses reveal that rMERUB has a β leaf pattern that promotes the exposure of epitopes, thus allowing antibody recognition. Evaluation of 33 samples (22=positive; 11=negative) was performed using in-house ELISA and this was compared with a commercial kit. The sensitivity was 100% (95% CI: 85-100) and specificity 90.91% (95% CI: 62-99). Excellent agreement (Kappa index = 0.9) was obtained between ELISA assays. The careful choice of epitopes and the high epitope density, coupled with simple-step purification, pinpoints rMERUB as a promising alternative for rubella diagnosis, with potential for the development of a diagnostic kit.

Cloning, expression, purification and functional analysis of a specific multi-epitope protein from multi drug resistance Acinetobacter baumannii.

Background and Objectives:Immunization is a promising strategy to combat against the life-threatening infections by Multi Drug Resistance Acinetobacter baumannii. In this study, we directed to design and evaluate the efficacy of a recombinant multi-epitope protein against this pathogen.Materials and Methods:Epitopes prediction was performed for candidate proteins OmpA and BAM complex (BamA, BamB, BamC, BamD, BamE) from A. baumannii, using immune-informatics tools with high affinity for the human HLA alleles. After expression and purification of the recombinant protein, its functional activity was confirmed by interaction with positive sera.Results:Cloning and expression of the desired multi-epitopes protein were verified. Circular Dichroism study showed the secondary structure and proper refolding of the recombinant protein was achieved and matched with computational prediction. There was a significant interaction between designed protein with antibodies presented in ICU patients’ and staff’s sera.Conclusion:The interaction of the recombinant protein with patients’ sera antibodies suggests that it may be a promising determinant protein for immunization against of MDR A. baumannii.

Antibodies induced by oral immunization of mice with a recombinant protein produced in tobacco plants harboring Bordetella pertussis epitopes.

Bordetella pertusis causes whooping cough or pertussis, disease that has not been eradicated and is reemerging despite the availability and massive application for decades of vaccines, such as Boostrix® which is an acellular vaccine harboring two regions of S1 subunit of the pertussis toxin, one region of filamentous hemagglutinin and one region of pertactin. In 2008, the World Health Organization estimated 16 million new cases and 95% occurred in developing countries with 195,000 children’s deaths. We attempt to improve the vaccine against whooping cough and reduce its production costs by obtaining plants and bacteria expressing a heterologous protein harboring pertactin, pertussis toxin, and filamentous hemagglutinin epitopes from B. pertussis and assessing its immunogenicity after oral administration to mice. First, we designed a synthetic gene that encodes a multiepitope, then it was cloned into a vector for transient transformation by infiltration of tobacco plants with low amounts of nicotine; the codon bias-optimized construct was also cloned into an Escherichia coli expression vector. Recombinant proteins from E. coli cells (PTF) and tobacco leaves (PTF-M3ʹ) were purified by nickel affinity with a yield of 0.740 mg of recombinant protein per g dry weight. Purified recombinant proteins were administered orally to groups of Balb/c mice using the Boostrix® vaccine and vehicle (PBS) as positive and negative controls, respectively. A higher mucosal and systemic antibody responses were obtained in mice receiving the PTF and PTF-M3ʹ proteins than Boostrix® or PBS. These findings prove the concept that oral administration of multiepitope recombinant proteins expressed in plants may be a potential edible vaccine.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11240-021-02107-1.

Evaluation of multi-epitope recombinant protein as a candidate for a contraceptive vaccine

Contraceptive vaccine (CV) is a valuable, non-invasive, and alternative method for purposeful contraception. Sperm antigens are useful targets for producing CVs due to their specialized expression in sperm. In this study, a recombinant protein containing three main sperm epitopes (IZUMO1, SACA3, and PH-20) was designed and evaluated as CV to control fertility in male mice. The chimeric recombinant protein was expressed and purified in E. coli. Male mice were immunized by 100 μg purified protein and sera were collected to assess IgG antibodies. Evaluating the reproductive performance, immunized male mice mated with normal-fertile female mice and mating rate and the number of newborns was studied. Immunized mice were sacrificed and necropsy and histopathology studies were conducted. The results revealed that the designed chimeric protein stimulated the immune system of the mice effectively. The level of IgG antibody was significantly higher in vaccinated mouse rather than control mouse. Eighty percent of the vaccinated mice became infertile and in the remaining ones, the number of children decreased to 4-6 offspring instead of 10–12 in normal mice. Histopathological studies showed that no organs including heart, brain, lung, liver, kidney and intestine were damaged. However, Normal spermatogenesis has been disrupted and necrotic spermatogonia cells were reported in Seminiferous tubules. We concluded that the designed chimeric protein containing IZUMO1, SACA3, and PH-20 epitopes can stimulate the immune system and cause male contraception without any side effects.

Development of an Indirect Chemiluminescence Immunoassay Using a Multiepitope Recombinant Protein To Specifically Detect Antibodies against Foot-and-Mouth Disease Virus Serotype O in Swine.

Foot-and-mouth disease virus (FMDV) has led to serious losses in animal husbandry worldwide. Seromonitoring of FMDV postvaccination is important for the control and eradication of foot-and-mouth disease (FMD) in regions and countries where vaccination is widespread. However, many commercial kits present high false-positive rates. In this study, a multiepitope-based indirect chemiluminescence immunoassay (ME-CLIA) was developed for specifically detecting antibodies against FMDV serotype O in swine sera. The developed method presented high diagnostic sensitivity and excellent diagnostic specificity, and it could detect a broad spectrum of antibodies against FMDV serotype O. The diagnostic performance, accuracy rate, and analytical sensitivity of ME-CLIA were compared with those of three commercial kits. The immune protection value of multiple-epitope recombinant vaccine detected using ME-CLIA was preliminarily determined by observation of clinical symptoms postimmunization challenge, the results of which indicated that the ME-CLIA can be employed as a matching detection method for evaluating multiple-epitope recombinant vaccine. The percent positive values of ME-CLIA determined using swine vaccinated with inactivated vaccine were significantly positively correlated with the titers of liquid-phase-blocking enzyme-linked immunosorbent assay (ELISA) (LBPE) (r = 0.8361; P < 0.0001). These results indicated that ME-CLIA is suitable for detection of antibodies against FMDV serotype O in swine and for potency evaluation of multiple-epitope and inactivated vaccines.