Role of bi-specific monoclonal antibodies in immunodiagnostic assay

This review paper highlights the use of bi-specific monoclonal antibodies (bsMAb) in the diagnostic assays for the early detection of pathogens of human infectious diseases such as severe acute respiratory syndrome (SARS), chikungunya (CHIKV), tuberculosis (TB) and dengue. Bi-specific monoclonal antibodies (bsMAb) are unique and artificially engineered macromolecules with two distinct binding sites, and are capable of binding two different antigens non-covalently. However, the traditional methods of diagnosis such as virus or bacterial isolation, and PCR amplification are quite expensive and time consuming. Bispecific monoclonal antibodies (bsMAb) are versatile, and can increase the specificity and sensitivity of detection in the suspected individuals. Therefore, immunodiagnostic assays using bsMAb are less expensive, and a large number of clinical samples could be analyzed at a faster rate for the detection of pathogens within a stipulated time. This could allow in developing a cost effective diagnostic kit, which is very useful particularly in the developing countries for the early assessment of the disease outbreak

Dengue Diagnostics: Current Scenario

There is an urgent requirement for specific, sensitive and inexpensive dengue diagnostic tools that can be used for clinical management, surveillance and outbreak investigations would permit early intervention to treat patients and prevent or control epidemics. Additionally, new techniques for the early detection of severe disease such as the use of biomarkers have the potential to decrease morbidity and mortality. Recent developments in rapid detection technologies offer the promise of improved diagnostics for case management and the early detection of dengue outbreaks. This short review summarizes the various diagnostics tests currently pursued

A Mini-review of Dengue Vaccine Development

About 100 million dengue cases are reported annually and an estimated 2.5 billion people are susceptible to the infection mostly in the tropical regions. Dengue virus is a member of the Flavivirus genus and consists of four serotypes (DV-1, DV-2, DV-3, and DV- 4), each of which is capable of causing dengue fever and the more severe dengue hemorrhagic fever or dengue shock syndrome. There is an urgent need to develop a safe and effective vaccine that induces protective immune response to all the four serotypes overcoming antibody dependent enhancement. At present there is no licensed vaccine or specific therapeutic measures for prevention or management of the fatal infection. This mini review outlines the different vaccine candidates that are at various stages of development

Targeting strategies and nanocarriers in vaccines and therapeutics

In the past few decades, remarkable advances have been made in the field of immunology and molecular biology. Even though the efficacy level, protein binding capacity and other pharmacological parameters are extraordinary, formulations have become more challenging in terms of making drugs or antigens reach specific sites of action, the release rate of a drug at the site of action, proper presentation of an antigen by antigen-presenting cells or dendritic cells and other pharmacokinetic and pharmacodynamic parameters of finished drug products and vaccines. The purpose of this review is to present a brief overview of the challenges to drug targeting, especially vaccines, as well as of different approaches designed to overcome these barriers

A Bispecific Antibody Based Assay Shows Potential for Detecting Tuberculosis in Resource Constrained Laboratory Settings

The re-emergence of tuberculosis (TB) as a global public health threat highlights the necessity of rapid, simple and inexpensive point-of-care detection of the disease. Early diagnosis of TB is vital not only for preventing the spread of the disease but also for timely initiation of treatment. The later in turn will reduce the possible emergence of multi-drug resistant strains of Mycobacterium tuberculosis. Lipoarabinomannan (LAM) is an important non-protein antigen of the bacterial cell wall, which is found to be present in different body fluids of infected patients including blood, urine and sputum. We have developed a bispecific monoclonal antibody with predetermined specificities towards the LAM antigen and a reporter molecule horseradish peroxidase (HRPO). The developed antibody was subsequently used to design a simple low cost immunoswab based assay to detect LAM antigen. The limit of detection for spiked synthetic LAM was found to be 5.0 ng/ml (bovine urine), 0.5 ng/ml (rabbit serum) and 0.005 ng/ml (saline) and that for bacterial LAM from M. tuberculosis H37Rv was found to be 0.5 ng/ml (rabbit serum). The assay was evaluated with 21 stored clinical serum samples (14 were positive and 7 were negative in terms of anti-LAM titer). In addition, all 14 positive samples were culture positive. The assay showed 100% specificity and 64% sensitivity (95% confidence interval). In addition to good specificity, the end point could be read visually within two hours of sample collection. The reported assay might be used as a rapid tool for detecting TB in resource constrained laboratory settings

Protein-Protein Interactions

Living organisms are almost exclusively comprised of four classes of molecules, namely, proteins, nucleic acids, polysaccharides, and lipids. Of these, barring lipids, all other classes can be regarded as macromolecules that are built from a limited number of building blocks or monomers. In the case of proteins, such building blocks are amino acids. Proteins are formed by polymerization of essentially twenty \u27standard\u27 amino acids. Yet, the myriad of proteins and their diverse functions, ranging from basic metabolism to structural and reproductive functions, can be astounding and constitute the very basis of life on Earth. For instance, an Escherichia coli bacterium contains over 4000 different proteins participating in virtually every life sustaining function of the cell.https://digitalcommons.chapman.edu/pharmacy_books/1023/thumbnail.jp

Development, Characterization, and Application of Monoclonal Antibodies against Severe Acute Respiratory Syndrome Coronavirus Nucleocapsid Protein▿

Five monoclonal antibodies (MAbs) against recombinant nucleocapsid protein (NP) of severe acute respiratory syndrome (SARS)-causing coronavirus (CoV) were developed by hybridoma technology. Epitope mapping by Western blotting showed that these anti-SARS-CoV NP MAbs bind to distinct domains of NP. These anti-SARS-CoV NP MAbs, with their high specificity, are potentially ideal candidates for developing early and sensitive diagnostic assays for SARS-CoV

Dendritic Cell Targeted Chitosan Nanoparticles for Nasal DNA Immunization against SARS CoV Nucleocapsid Protein

This work investigates the formulation and in vivo efficacy of dendritic cell (DC) targeted plasmid DNA loaded biotinylated chitosan nanoparticles for nasal immunization against nucleocapsid (N) protein of severe acute respiratory syndrome coronavirus (SARS-CoV) as antigen. The induction of antigen-specific mucosal and systemic immune response at the site of virus entry is a major challenge for vaccine design. Here, we designed a strategy for non-invasive receptor mediated gene delivery to nasal resident DCs. The pDNA loaded biotinylated chitosan nanoparticles were prepared using a complex coacervation process and characterized for size, shape, surface charge, plasmid loading and protection against nuclease digestion. The pDNA loaded biotinylated chitosan nanoparticles were targeted with bifunctional fusion protein (bfFp) vector for achieving DC selective targeting. The bfFp is a recombinant fusion protein consisting of truncated core-streptavidin fused with anti-DEC-205 single chain antibody (scFv). The core-streptavidin arm of fusion protein binds with biotinylated nanoparticles, while anti-DEC-205 scFv imparts targeting specificity to DC DEC-205 receptor. We demonstrate that intranasal administration of bfFp targeted formulations along with anti-CD40 DC maturation stimuli enhanced magnitude of mucosal IgA as well as systemic IgG against N protein. The strategy led to the detection of augmented levels of N protein specific systemic IgG and nasal IgA antibodies. However, following intranasal delivery of naked pDNA no mucosal and systemic immune responses were detected. A parallel comparison of targeted formulations using intramuscular and intranasal route showed that the intramuscular route is superior for induction of systemic IgG responses compared with the intranasal route. Our results suggest that targeted pDNA delivery through non-invasive intranasal route can be a strategy for designing low-dose vaccines

Dendritic Cell Targeted Chitosan Nanoparticles for Nasal DNA Immunization against SARS CoV Nucleocapsid Protein

This work investigates the formulation and <i>in vivo</i> efficacy of dendritic cell (DC) targeted plasmid DNA loaded biotinylated chitosan nanoparticles for nasal immunization against nucleocapsid (N) protein of severe acute respiratory syndrome coronavirus (SARS-CoV) as antigen. The induction of antigen-specific mucosal and systemic immune response at the site of virus entry is a major challenge for vaccine design. Here, we designed a strategy for noninvasive receptor mediated gene delivery to nasal resident DCs. The pDNA loaded biotinylated chitosan nanoparticles were prepared using a complex coacervation process and characterized for size, shape, surface charge, plasmid DNA loading and protection against nuclease digestion. The pDNA loaded biotinylated chitosan nanoparticles were targeted with bifunctional fusion protein (bfFp) vector for achieving DC selective targeting. The bfFp is a recombinant fusion protein consisting of truncated core-streptavidin fused with anti-DEC-205 single chain antibody (scFv). The core-streptavidin arm of fusion protein binds with biotinylated nanoparticles, while anti-DEC-205 scFv imparts targeting specificity to DC DEC-205 receptor. We demonstrate that intranasal administration of bfFp targeted formulations along with anti-CD40 DC maturation stimuli enhanced magnitude of mucosal IgA as well as systemic IgG against N protein. The strategy led to the detection of augmented levels of N protein specific systemic IgG and nasal IgA antibodies. However, following intranasal delivery of naked pDNA no mucosal and systemic immune responses were detected. A parallel comparison of targeted formulations using intramuscular and intranasal routes showed that the intramuscular route is superior for induction of systemic IgG responses compared with the intranasal route. Our results suggest that targeted pDNA delivery through a noninvasive intranasal route can be a strategy for designing low-dose vaccines