Monoclonal antibodies

The effect of polyclonal and monoclonal based antibodies as promising potential therapy for treatment of sepsis: A systematic review

While mortality caused by sepsis remains an unsolved problem, studies showed conflicting results about effectiveness of monoclonal and polyclonal antibodies in patients suffering sepsis. For this reason, this current study provides an update of review clinical randomized trial studies until March 2024. The main object of this study is to determine effects of monoclonal and polyclonal antibodies on mortality rate and hospitalization of patients suffering sepsis. Search of Scopus, Web of science, EMBASE, PubMed and Cochrane were performed and randomized controlled trials which conducted in patients with septic shock or bacterial sepsis were included. Two reviewers assessed all searched trials for eligibility according to already defined criteria and did data collection and analyses afterwards. Present study showed monoclonal and polyclonal antibodies are a safe strategy with mild-to-moderate adverse effects. However, most studies indicate no significant change among inter-and intra-group comparison (p > 0.05) and further studies are needed, results showed an increase in survival rate, ventilator-and ICU-free days, resolve organ dysfunction, mediating inflammation related cytokines.

Development and characterization of a novel specific monoclonal antibody against mink enteritis virus and its antigen epitope analysis

This study prepared a novel monoclonal antibody (MAb) against mink enteritis parvovirus (MEV) and identified its antigen epitope. The antibody subclass is identified as IgG1, the titers of the MAb is up to 1:1 × 106 and keeps stably after low-temperature storage for 9 months or 11 passages of the MAb cells. The MAb can specifically recognize MEV in the cells in IFA, but not Aleutian disease virus (ADV) or canine distemper virus (CDV). Its antigen epitope was identified as a polypeptide containing 5 key amino acids (378YAFGR382) and the homology in 20 MEV strains, 4 canine parvovirus strains, and 4 feline panleukopenia virus strains was 100%. This study supplies a biological material for developing new methods to detect MEV.

Heat-induced structural and chemical changes to a computationally designed miniprotein

The de novo design of miniprotein inhibitors has recently emerged as a new technology to create proteins that bind with high affinity to specific therapeutic targets. Their size, ease of expression, and apparent high stability makes them excellent candidates for a new class of protein drugs. However, beyond circular dichroism melts and hydrogen/deuterium exchange experiments, little is known about their dynamics, especially at the elevated temperatures they seemingly tolerate quite well. To address that and gain insight for future designs, we have focused on identifying unintended and previously overlooked heat-induced structural and chemical changes in a particularly stable model miniprotein, EHEE_rd2_0005. Nuclear magnetic resonance (NMR) studies suggest the presence of dynamics on multiple time and temperature scales. Transiently elevating the temperature results in spontaneous chemical deamidation visible in the NMR spectra, which we validate using both capillary electrophoresis and mass spectrometry (MS) experiments. High temperatures also result in greatly accelerated intrinsic rates of hydrogen exchange and signal loss in NMR heteronuclear single quantum coherence spectra from local unfolding. These losses are in excellent agreement with both room temperature hydrogen exchange experiments and hydrogen bond disruption in replica exchange molecular dynamics simulations. Our analysis reveals important principles for future miniprotein designs and the potential for high stability to result in long-lived alternate conformational states.

Development of Monoclonal Antibody against PirB and Establishment of a Colloidal Gold Immunochromatographic Assay for the Rapid Detection of AHPND-Causing Vibrio

Acute hepatopancreatic necrosis disease (AHPND) poses a significant threat to shrimp aquaculture worldwide, necessitating the accurate and rapid detection of the pathogens. However, the increasing number of Vibrio species that cause the disease makes diagnosis and control more difficult. This study focuses on developing a monoclonal antibody against the Photorhabdus insect-related (Pir) toxin B (PirB), a pivotal virulence factor in AHPND-causing Vibrio, and establishing a colloidal gold immunochromatographic assay for the enhanced early diagnosis and monitoring of AHPND. Monoclonal antibodies targeting PirB were developed and utilized in the preparation of colloidal-gold-labeled antibodies for the immunochromatographic assay. The specificity and sensitivity of the assay were evaluated through various tests, including antibody subclass detection, affinity detection, and optimal labeling efficiency assessment. The developed PirB immunochromatographic test strips exhibited a good specificity, as demonstrated by the positive detection of AHPND-causing Vibrio and negative results for non-AHPND-causing Vibrio. The study highlights the potential of the developed monoclonal antibody and immunochromatographic assay for the effective detection of AHPND-causing Vibrio. Further optimization is needed to enhance the sensitivity of the test strips for improved practical applications in disease prevention and control in shrimp aquaculture.

Development of monoclonal antibodies against oropouche virus and its applicability to immunohistochemical diagnosis

Orthobunyavirus oropouche ense virus (OROV), the causative agent of Oropouche fever, is widely dispersed in Brazil and South America, causing sporadic outbreaks. Due to the similarity of initial clinical symptoms caused by OROV with other arboviruses found in overlapping geographical areas, differential diagnosis is challenging. As for most neglected tropical diseases, there is a shortage of reagents for diagnosing and studying OROV pathogenesis. We therefore developed and characterized mouse monoclonal antibodies and, one of them recognizes the OROV nucleocapsid in indirect immunofluorescent (IFA) and immunohistochemistry (IHC) assays. Considering that it is the first monoclonal antibody produced for detecting OROV infections, we believe that it will be useful not only for diagnostic purposes but also for performing serological surveys and epidemiological surveillance on the dispersion and prevalence of OROV in Brazil and South America.

DOTAD: A Database of Therapeutic Antibody Developability

The development of therapeutic antibodies is an important aspect of new drug discovery pipelines. The assessment of an antibody's developability-its suitability for large-scale production and therapeutic use-is a particularly important step in this process. Given that experimental assays to assess antibody developability in large scale are expensive and time-consuming, computational methods have been a more efficient alternative. However, the antibody research community faces significant challenges due to the scarcity of readily accessible data on antibody developability, which is essential for training and validating computational models. To address this gap, DOTAD (Database Of Therapeutic Antibody Developability) has been built as the first database dedicated exclusively to the curation of therapeutic antibody developability information. DOTAD aggregates all available therapeutic antibody sequence data along with various developability metrics from the scientific literature, offering researchers a robust platform for data storage, retrieval, exploration, and downloading. In addition to serving as a comprehensive repository, DOTAD enhances its utility by integrating a web-based interface that features state-of-the-art tools for the assessment of antibody developability. This ensures that users not only have access to critical data but also have the convenience of analyzing and interpreting this information. The DOTAD database represents a valuable resource for the scientific community, facilitating the advancement of therapeutic antibody research. It is freely accessible at http://i.uestc.edu.cn/DOTAD/ , providing an open data platform that supports the continuous growth and evolution of computational methods in the field of antibody development.

Antibody mimetics: The next generation antibody engineering, a retrospective and prospective analysis

Antibody mimetics represent the fourth generation of antibody engineering, following polyclonal antibodies, monoclonal antibodies, and genetically engineered antibody fragments. Despite cumulative studies highlighting the advantages of antibody mimetics, including enhanced recognition properties, superior affinity, stability, penetrability, and cost-effectiveness, a comprehensive review of this evolving field is notably absent. In this study, spanning 1986-2023 and analyzing 24,318 publications, we undertake a retrospective and prospective analysis to elucidate the evolution roadmap of antibody mimetics, providing insights into the current landscape, global contributions, and future trajectories. Concurrently, our aim is to establish standardized terminology and delineate the research scope within the realm of antibody mimetics. These endeavors not only chart the trajectory and scope of antibody mimetics research but also underscore its potential to revolutionize medicine, technology, and science.

Monoclonal Antibodies and Antibody-drug Conjugates as Emerging Therapeutics for Breast Cancer Treatment

When breast cells divide and multiply out of control, it is called breast cancer. Symptoms include lump formation in the breast, a change in the texture or color of the breast, or a discharge from the nipple. Local or systemic therapy is frequently used to treat breast cancer. Surgical and radiation procedures limited to the affected area are examples of local management. There has been significant worldwide progress in the development of monoclonal antibodies (mAbs) since 1986, when the first therapeutic mAb, Orthoclone OKT3, became commercially available. mAbs can resist the expansion of cancer cells by inducing the destruction of cellular membranes, blocking immune system inhibitors, and preventing the formation of new blood vessels. mAbs can also target growth factor receptors. Understanding the molecular pathways involved in tumor growth and its microenvironment is crucial for developing effective targeted cancer therapeutics. Due to their unique properties, mAbs have a wide range of clinical applications. Antibody-drug conjugates (ADCs) are drugs that improve the therapeutic index by combining an antigen-specific antibody with a payload. This review focuses on the therapeutic applications, mechanistic insights, characteristics, safety aspects, and adverse events of mAbs like trastuzumab, bevacizumab, pertuzumab, ertumaxomab, and atezolizumab in breast cancer treatment. The creation of novel technologies utilizing modified antibodies, such as fragments, conjugates, and multi-specific antibodies, must be a central focus of future studies. This review will help scientists working on developing mAbs to treat cancers more effectively.

A Sensitive and Specific Monoclonal Antibody Based Enzyme-Linked Immunosorbent Assay for the Rapid Detection of Pretilachlor in Grains and the Environment

Pretilachlor is a chloroacetamide herbicide mainly used for weed and broadleaf weed control in rice, that is widely utilized in China. In order to detect the residue of pretilachlor in the environment and food, a highly sensitive and specific monoclonal antibody (mAb) against pretilachlor was prepared, and the half maximum inhibitory concentration (IC50) of the monoclonal antibody was validated to be 31.47 ± 2.35 μg/L. An indirect competitive ELISA (ic-ELISA) based on the antibody with a linear range of 6.25~100 μg/L was developed. The specificity of the antibody was explained by computer simulations and experimental validation. The mAb exhibited negligible cross-reactivity towards alachlor, acetochlor, propisochlor, butachlor, and metalaxyl, and the limits of detection (LOD) for pretilachlor in lake, rice, and soil samples were 4.83~5.23 μg/L. The recoveries of all samples were 78.3~91.3%. The reliability of the ic-ELISA method for residue detection of pretilachlor in the environment and grains was confirmed using high performance liquid chromatography.

Development of monoclonal antibodies against Rhodococcus equi virulence-associated protein N and their application to pathological diagnosis

IMPORTANCE

Rhodococcus equi can cause infection in ruminants, and its pathogenicity is suggested to be associated with VapN. Despite its wide distribution, no immunological diagnostic method has been developed for VapN-producing R. equi. Against this background, we attempted to develop monoclonal antibodies targeting VapN and assess their application in immunostaining. In the study, mice were immunized with recombinant VapN, and cell fusion and cloning by limiting dilution permitted the generation of three antibody-producing hybridomas. The utility of the antibodies produced from the hybridomas in immunostaining was demonstrated using an infected mouse model, and the antibodies were further applied to previously reported cases of R. equi infection in goats and cattle. Although the 4H4 antibody induced the strongest reactions, the reactivity of two other antibodies was improved by antigen retrieval. Our monoclonal antibodies will be utilized to support the definitive diagnosis of suspected R. equi infection, including cases that were previously missed.

Drug-drug interactions between COVID-19 drug therapies and antidepressants

INTRODUCTION

Antidepressants are widely used for the pharmacological treatment of anxiety and mood disorders. Since the eruption of the SARS-COV-2 pandemic and the later development of targeted treatments against COVID-19, inevitably many patients receive antidepressants as well as targeted treatments against COVID-19 against COVID-19. Co-administration of antidepressants with COVID-19 therapeutics has the potential of drug-drug interactions, of varying severity and clinical significance.

AREAS COVERED

This is a curated narrative review of the current state of the art regarding drug-drug interactions between COVID-19 therapeutics and medications licensed for the pharmacotherapy of depression. A systematic search of electronic databases, using as keywords the international nonproprietaty names of currently approved COVID-19 therapeutics and antidepressants was performed, and additionally online interaction checker tools were consulted. Derived data were synthesized for each COVID-19 therapeutic and presented with up-to-date guidance.

EXPERT OPINION

Several COVID-19 therapeutics have potential for drug-drug interactions with antidepressants. Remdesivir and Nirmatrelvir-Ritonavir have the higher risk, whereas several monoclonal antibodies appear safer. The most serious drug-drug interactions (serotonin syndrome and QTc prolongation) require close monitoring; however, DDI toward reducing the efficacy of antidepressants may be difficult to recognize. As COVID-19 treatment protocols take precedence, psychiatrists should exert flexibility in antidepressant use and proactively monitor treatment progress.

Expression of a SAG protein with a CAP domain from Eimeria necatrix and its role in invasion and immunoprotection

Eimeria necatrix is a high pathogenic pathogen, which seriously endangers the poultry industry. The surface antigens (SAGs) of Apicomplexa are a kind of membrane protein anchored on the surface of the parasites through its carboxyl terminal glycosylphosphatidylinositol (GPI) structure. However, little is known about GPI-linked surface proteins in E. necatrix. In the present work, the E. necatrix sag gene (Ensag-CAP) was amplified and cloned for expression of the recombinant protein (rEnSAG-CAP). The full length Ensag-CAP gene was 813 bp, coding 270 amino acids with a predicated molecular weight of 28.86 kDa and contained a CAP domain with four sequence motifs CAP1, CAP2, CAP3 and CAP4. The rEnSAG-CAP was about 32 kDa and mainly expressed in a soluble form. Western blot analysis indicated that the rEnSAG-CAP could be recognized by anti-rEnSAG-CAP monoclonal antibody (anti-rEnSAG-CAP McAb) and the convalescent serum of chicken infected with E. necatrix. Native protein of EnSAG-CAP was detected in second-generation merozoites (MZ-2) using anti-rEnSAG-CAP polyclonal antibody (anti-rEnSAG-CAP pAb). The findings from the indirect immunofluorescence assay and enzyme digestion utilizing Bacillus cereus phosphoinositide-specific phospholipase C (PI-PLC) revealed that EnSAG-CAP predominantly localized at the surfaces of SZ and MZ-2 via a GPI anchor. It was observed that EnSAG-CAP can be cleaved from MZ-2 by PI-PLC. Real-time quantitative PCR (qPCR) analysis showed that transcript levels of Ensag-CAP in MZ-2 was significantly higher than that in SZ (P < 0.05). The anti-rEnSAG-CAP McAb in vitro could significantly inhibit the sporozoite invasion into MDBK cells (P < 0.01), which suggests that the protein might participate in sporozoite invasion into MDBK cells. rEnSAG-CAP afforded an immune protection against E. necatrix. The ACI value was 164.99 in the chickens immunized with 200 µg rEnSAG-CAP. Chickens immunized with rEnSAG-CAP had a significantly higher antigen-specific serum IgY response (P < 0.0001). The data indicates that EnSAG-CAP could serve as a potential candidate antigen for the development of a recombinant coccidiosis vaccine.

Preparation of polyclonal antibodies against the Drosophila deacetylases SIRT 6 and SIRT 7

SIRT6 and SIRT7, as members of the Sirtuins family, are indispensable for the growth and development of Drosophila. They play crucial roles in maintaining genome stability, regulating metabolic senescence, and controlling tumorigenesis. To investigate their involvement in the Drosophila life cycle, we focused on describing the expression and purification of recombinant Drosophila SIRT6 and SIRT7 proteins. Subsequently, these proteins were utilized for generating polyclonal antibodies against Drosophila SIRT6 and SIRT7. The recombinant expression plasmid was introduced into E. coli cells to enable the production of SIRT6 and SIRT7 proteins. Following immunizations of New Zealand white rabbits and guinea pigs with the recombinant proteins as antigens, specific polyclonal antisera against both proteins were obtained. After purification, the specificity of SIRT6 and SIRT7 was confirmed using ELISA and western blot analyses, demonstrating strong specificity. These antibodies hold promise for the development of detection assays required for further research.

From cell factories to patients: Stability challenges in biopharmaceuticals manufacturing and administration with mitigation strategies

Active ingredients of biopharmaceuticals consist of a wide array of biomolecular structures, including those of enzymes, monoclonal antibodies, nucleic acids, and recombinant proteins. Recently, these molecules have dominated the pharmaceutical industry owing to their safety and efficacy. However, their manufacturing is hindered by high cost, inadequate batch-to-batch equivalence, inherent instability, and other quality issues. This article is an up-to-date review of the challenges encountered during different stages of biopharmaceutical production and mitigation of problems arising during their development, formulation, manufacturing, and administration. It is a broad overview discussion of stability issues encountered during product life cycle i.e., upstream processing (aggregation, solubility, host cell proteins, color change), downstream bioprocessing (aggregation, fragmentation), formulation, manufacturing, and delivery to patients.

MILKSHAKE Western blot and Sundae ELISA: We all scream for better antibody validation

Knowing that an antibody's sensitivity and specificity is accurate is crucial for reliable data collection. This certainty is especially difficult to achieve for antibodies (Abs) which bind post-translationally modified proteins. Here we describe two validation methods using surrogate proteins in western blot and ELISA. The first method, which we termed "MILKSHAKE" is a modified maltose binding protein, hence the name, that is enzymatically conjugated to a peptide from the chosen target which is either modified or non-modified at the residue of interest. The surety of the residue's modification status can be used to confirm Ab specificity to the target's post-translational modification (PTM). The second method uses a set of surrogate proteins, which we termed "Sundae". Sundae consists of a set of modified maltose binding proteins with a genetically encoded target sequence, each of which contains a single amino acid substitution at one position of interest. With Sundae, Abs can be evaluated for binding specificities to all twenty amino acids at a single position. Combining MILKSHAKE and Sundae methods, Ab specificity can be determined at a single-residue resolution. These data improve evaluation of commercially available Abs and identify off-target effects for Research-Use-Only and therapeutic Abs.

Aerosol pulmonary immune engineering

Aerosolization of immunotherapies poses incredible potential for manipulating the local mucosal-specific microenvironment, engaging specialized pulmonary cellular defenders, and accessing mucosal associated lymphoid tissue to redirect systemic adaptive and memory responses. In this review, we breakdown key inhalable immunoengineering strategies for chronic, genetic, and infection-based inflammatory pulmonary disorders, encompassing the historic use of immunomodulatory agents, the transition to biological inspired or derived treatments, and novel approaches of complexing these materials into drug delivery vehicles for enhanced release outcomes. Alongside a brief description of key immune targets, fundamentals of aerosol drug delivery, and preclinical pulmonary models for immune response, we survey recent advances of inhaled immunotherapy platforms, ranging from small molecules and biologics to particulates and cell therapies, as well as prophylactic vaccines. In each section, we address the formulation design constraints for aerosol delivery as well as advantages for each platform in driving desirable immune modifications. Finally, prospects of clinical translation and outlook for inhaled immune engineering are discussed.

Identification and Characterization of α-Actinin 1 of Histomonas meleagridis and Its Potential Vaccine Candidates against Histomonosis

Histomonas meleagridis is a protozoan parasite that causes histomonosis in gallinaceous birds such as turkeys and chickens. Since the banning and restricted usage of effective drugs such as nitarsone, 80-100% morbidity and mortality occur in turkeys and 20-30% mortality in chickens. New ideas are needed to resolve the re-emergence of histomonosis in poultry. In this study, the α-actinin encoding gene from H. meleagridis was cloned. The 1839-bp gene encoding 612 amnio acids showed close phylogenetic relationships with Trichomonas vaginalis and Tritrichomonas foetus. It was then inserted into the prokaryotic expression vector pET28a(+) and induced with isopropyl-β-D-thiogalactopyranoside. A 73 kDa recombinant protein rHmα-actinin 1 was obtained and purified with a Ni-NTA chromatography column. rHmα-actinin 1 was recognized by mouse anti-rHmα-actinin 1 polyclonal antibody, mouse anti-rHmα-actinin 1 monoclonal antibody, and rehabilitation sera from H. meleagridis infected chickens. Native α-actinin 1 in the total proteins of H. meleagridis can also be detected with mouse anti-rHmα-actinin monoclonal antibody. Immunolocalization assays showed that Hmα-actinin 1 was mainly distributed in the cytoplasm of virulent histomonads JSYZ-D9 and in the peripheral regions (near the plasma membrane) of attenuated histomonads JSYZ-D195. Based on in vivo experiment, when chickens were subcutaneously immunized with rHmα-actinin 1 at 5 and 12 days old and then challenged with H. meleagridis at 19 days old, rHmα-actinin 1 reduced the lesion scores 12 days after infection (31 days old) and increased the body weight gain during the challenged period (19-31 days old). Furthermore, it also strengthened the cellular and humoral immune responses 7 days after the second immunization (19 days old). In conclusion, Hmα-actinin 1 could be used as a candidate antigen to develop vaccines against chicken histomonosis.

Flow Cytometry: The Next Revolution

Unmasking the subtleties of the immune system requires both a comprehensive knowledge base and the ability to interrogate that system with intimate sensitivity. That task, to a considerable extent, has been handled by an iterative expansion in flow cytometry methods, both in technological capability and also in accompanying advances in informatics. As the field of fluorescence-based cytomics matured, it reached a technological barrier at around 30 parameter analyses, which stalled the field until spectral flow cytometry created a fundamental transformation that will likely lead to the potential of 100 simultaneous parameter analyses within a few years. The simultaneous advance in informatics has now become a watershed moment for the field as it competes with mature systematic approaches such as genomics and proteomics, allowing cytomics to take a seat at the multi-omics table. In addition, recent technological advances try to combine the speed of flow systems with other detection methods, in addition to fluorescence alone, which will make flow-based instruments even more indispensable in any biological laboratory. This paper outlines current approaches in cell analysis and detection methods, discusses traditional and microfluidic sorting approaches as well as next-generation instruments, and provides an early look at future opportunities that are likely to arise.

Rethinking Biosynthesis of Aclacinomycin A

Aclacinomycin A (ACM-A) is an anthracycline antitumor agent widely used in clinical practice. The current industrial production of ACM-A relies primarily on chemical synthesis and microbial fermentation. However, chemical synthesis involves multiple reactions which give rise to high production costs and environmental pollution. Microbial fermentation is a sustainable strategy, yet the current fermentation yield is too low to satisfy market demand. Hence, strain improvement is highly desirable, and tremendous endeavors have been made to decipher biosynthesis pathways and modify key enzymes. In this review, we comprehensively describe the reported biosynthesis pathways, key enzymes, and, especially, catalytic mechanisms. In addition, we come up with strategies to uncover unknown enzymes and improve the activities of rate-limiting enzymes. Overall, this review aims to provide valuable insights for complete biosynthesis of ACM-A.

Application Progress of the Single Domain Antibody in Medicine

The camelid-derived single chain antibody (sdAb), also termed VHH or nanobody, is a unique, functional heavy (H)-chain antibody (HCAb). In contrast to conventional antibodies, sdAb is a unique antibody fragment consisting of a heavy-chain variable domain. It lacks light chains and a first constant domain (CH1). With a small molecular weight of only 12~15 kDa, sdAb has a similar antigen-binding affinity to conventional Abs but a higher solubility, which exerts unique advantages for the recognition and binding of functional, versatile, target-specific antigen fragments. In recent decades, with their unique structural and functional features, nanobodies have been considered promising agents and alternatives to traditional monoclonal antibodies. As a new generation of nano-biological tools, natural and synthetic nanobodies have been used in many fields of biomedicine, including biomolecular materials, biological research, medical diagnosis and immune therapies. This article briefly overviews the biomolecular structure, biochemical properties, immune acquisition and phage library construction of nanobodies and comprehensively reviews their applications in medical research. It is expected that this review will provide a reference for the further exploration and unveiling of nanobody properties and function, as well as a bright future for the development of drugs and therapeutic methods based on nanobodies.

PEGylation Prolongs the Half-Life of Equine Anti-SARS-CoV-2 Specific F(ab')2

Therapeutic antibodies-F(ab')₂ obtained from hyperimmune equine plasma could treat emerging infectious diseases rapidly because of their high neutralization activity and high output. However, the small-sized F(ab')₂ is rapidly eliminated by blood circulation. This study explored PEGylation strategies to maximize the half-life of equine anti-SARS-CoV-2 specific F(ab')₂. Equine anti-SARS-CoV-2 specific F(ab')₂ were combined with 10 KDa MAL-PEG-MAL in optimum conditions. Specifically, there were two strategies: Fab-PEG and Fab-PEG-Fab, F(ab')₂ bind to a PEG or two PEG, respectively. A single ion exchange chromatography step accomplished the purification of the products. Finally, the affinity and neutralizing activity was evaluated by ELISA and pseudovirus neutralization assay, and ELISA detected the pharmacokinetic parameters. The results displayed that equine anti-SARS-CoV-2 specific F(ab')₂ has high specificity. Furthermore, PEGylation F(ab')₂-Fab-PEG-Fab had a longer half-life than specific F(ab')₂. The serum half-life of Fab-PEG-Fab, Fab-PEG, and specific F(ab')₂ were 71.41 h, 26.73 h, and 38.32 h, respectively. The half-life of Fab-PEG-Fab was approximately two times as long as the specific F(ab')₂. Thus far, PEGylated F(ab')₂ has been prepared with high safety, high specificity, and a longer half-life, which could be used as a potential treatment for COVID-19.

Drug-induced cutaneous pseudolymphoma: A systematic review of the literature

Drug-induced cutaneous pseudolymphoma (CPL) is a common form of pseudolymphoma and there are numerous drugs associated with it. In this study, we performed a systematic review of the literature by searching PubMed/Medline and Embase databases to determine the most common drugs responsible for CPL and to define the demographic, clinical, histopathological and immunopathological characteristics of patients (updated on 30 December 2020). From 883 initially found articles, 56 studies (89 reported cases) were included. The mean age of patients was 54.4 ± 17.7 (ranging 8-86) years, and 46 (51.7%) were men. The median time interval between drug intake and CPL occurrence was 120 days (range 1-7300 days). The shortest median time interval between taking the drug and the onset of the disease was observed among patients taking antidepressants (60 days) (range 7-540) and the longest median time interval was observed in individuals using immunomodulators (300 days) (range 3-7300). The most-reported drug categories causing CPL were anti-hypertensives (17.9%), anticonvulsants (14.6%), monoclonal antibodies (13.4%) and antidepressants (11.2%). Moreover, the most common drugs were phenytoin (6.7%), amlodipine (5.6%), fluoxetine (5.6%) and carbamazepine (4.4%). Histopathological evaluation of 76 cases revealed 62 (81.5%) reports of T-cell infiltrations. Furthermore, positive reports of CD4 (94.0%), CD8 (93.0%) and CD30 (87.5%) were noted. The lowest prevalence of CD30-positive reports was observed among monoclonal antibodies. In conclusion, anti-hypertensives, anti-convulsants, monoclonal antibodies and anti-depressants are the most common drugs responsible for CPL. It mostly presents in middle-aged patients with almost no gender difference as pruritic papules, nodules and plaques.

State of the art in epitope mapping and opportunities in COVID-19

The understanding of any disease calls for studying specific biological structures called epitopes. One important tool recently drawing attention and proving efficiency in both diagnosis and vaccine development is epitope mapping. Several techniques have been developed with the urge to provide precise epitope mapping for use in designing sensitive diagnostic tools and developing rpitope-based vaccines (EBVs) as well as therapeutics. In this review, we will discuss the state of the art in epitope mapping with a special emphasis on accomplishments and opportunities in combating COVID-19. These comprise SARS-CoV-2 variant analysis versus the currently available immune-based diagnostic tools and vaccines, immunological profile-based patient stratification, and finally, exploring novel epitope targets for potential prophylactic, therapeutic or diagnostic agents for COVID-19.

Immunoprecipitation: Variations, Considerations, and Applications

Immunoprecipitation (IP) refers to methods of affinity chromatography that enrich and/or purify a specific protein from a complex mixture using a specific antibody immobilized on a solid support. Several operations and processes that are dependent on the isolation, concentration, and modification of proteins have seen improvement in their selectivity and separation based on the integration of IP-specific reactions into their workflows. This relatively simple principle has contributed significantly to our understanding of proteins and their behaviors and has become increasingly fundamental to most protein characterization studies today. In this chapter, we review the basic principles of IP and the several factors that influence each stage, and subsequently the success, of an IP experiment. Moreover, variations in application of the IP principle are discussed, and the adaptability of the techniques based on such is highlighted in the provision of two IP workflows to purify a particular protein from an entire cellular proteosome. These workflows cover the preparation and fractionation of crude cellular lysate into individual subcellular fractions, through to both "batch" and "column"-based extractions of the target protein of interest. Protocols for determining the validity of the workflows, and the presence/abundance of the protein of interest, are also briefly described.

Bispecific Aptamer-Based Recognition-then-Conjugation Strategy for PD1/PDL1 Axis Blockade and Enhanced Immunotherapy

Cytotoxic T cells initiate antitumor effects mainly through direct interactions with tumor cells. As a counter to this, tumor cells can put the brakes on such T-cell activity via specific linkage between programmed death ligand 1 (PDL1) and its receptor programmed cell death protein 1 (PD1). Bispecific inhibitors that enabled synchronous blockade of PD1 and PDL1, thereby releasing the brakes on T-cell antitumor activity, should significantly improve the efficacy of immune checkpoint blockade (ICB) therapy. In this work, we identified a DNA aptamer, Ap3, that could specifically recognize PDL1 on tumor cells and competed with the binding of PD1. By integrating Ap3 with an anti-PD1 aptamer, the bispecific aptamer Ap3-7c was constructed, and it showed promise for improving the T-cell immune response. We further designed a dibenzocyclooctyne (DBCO)-labeled bispecific aptamer, D-Ap3-7c, allowing covalent conjugation of aptamers onto PD1 and PDL1 after specific cell recognition. Our in vivo studies showed that this recognition-then-conjugation strategy could induce a potent immunological effect against tumors. This work is expected to provide clues for antitumor immunotherapy.

The immunolocalization of cluster of differentiation 31, phalloidin and alpha smooth muscle actin on vascular network of normal and ischemic rat brain

Cluster of differentiation 31 (CD31), phalloidin and alpha smooth muscle actin (α-SMA) have been widely applied to label the cerebral blood vessels in the past years. Although CD31 is mainly used as endothelial marker in determining the cerebral capillaries, it seems likely that its labeling efficiency is closely correlated with the antibodies from the polyclonal or monoclonal one, as well as the conditions of blood vessels. In order to test this phenomenon, we compared the labeling characteristics of goat polyclonal anti-CD31 (gP-CD31) and mouse monoclonal anti-CD31 (mM-CD31) with those of phalloidin and α-SMA on the rat brain in health and ischemia/reperfusion (I/R) with the middle cerebral artery occlusion. By multiple immunofluorescence staining, it was found that gP-CD31 labeling expressed extensively on the cerebral capillaries forming the vascular networks on the normal and ischemic regions, but mM-CD31 labeling mainly presented on the capillaries in the ischemic region. In contrast to the vascular labeling with gP-CD31, phalloidin and α-SMA were mainly expressed on the wall of cortical penetrating arteries, and less on that of capillaries. By three-dimensional reconstruction analysis, it was clearly shown that gP-CD31 labeling was mainly located on the lumen side of vascular wall and was surrounded by phalloidin labeling and α-SMA labeling. These results indicate that gP-CD31 is more sensitive than mM-CD31 for labeling the cerebral vasculature, and is highly compatible with phalloidin and α-SMA for evaluating the cerebral vascular networks under the physiological and pathological conditions.

Comprehensive evaluation of peptide de novo sequencing tools for monoclonal antibody assembly

Monoclonal antibodies are biotechnologically produced proteins with various applications in research, therapeutics and diagnostics. Their ability to recognize and bind to specific molecule structures makes them essential research tools and therapeutic agents. Sequence information of antibodies is helpful for understanding antibody-antigen interactions and ensuring their affinity and specificity. De novo protein sequencing based on mass spectrometry is a valuable method to obtain the amino acid sequence of peptides and proteins without a priori knowledge. In this study, we evaluated six recently developed de novo peptide sequencing algorithms (Novor, pNovo 3, DeepNovo, SMSNet, PointNovo and Casanovo), which were not specifically designed for antibody data. We validated their ability to identify and assemble antibody sequences on three multi-enzymatic data sets. The deep learning-based tools Casanovo and PointNovo showed an increased peptide recall across different enzymes and data sets compared with spectrum-graph-based approaches. We evaluated different error types of de novo peptide sequencing tools and their performance for different numbers of missing cleavage sites, noisy spectra and peptides of various lengths. We achieved a sequence coverage of 97.69-99.53% on the light chains of three different antibody data sets using the de Bruijn assembler ALPS and the predictions from Casanovo. However, low sequence coverage and accuracy on the heavy chains demonstrate that complete de novo protein sequencing remains a challenging issue in proteomics that requires improved de novo error correction, alternative digestion strategies and hybrid approaches such as homology search to achieve high accuracy on long protein sequences.

An Executed Plan to Combat COVID-19 in the United States

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in late 2019. To date, this coronavirus is responsible for greater than 90 million cases in the United States and more than 1 million confirmed deaths. When this virus came to the United States, testing was unorganized, no effective treatments were known, and no vaccines had been discovered. A plan to correct these deficiencies through cooperative science and efficient clinical trials was implemented to combat this novel virus. This plan developed efficient and inexpensive tests, highly effective medicines to treat and prevent disease progression, and vaccines to immunize the population.

Advanced hybridoma technology for selective production of high-affinity monoclonal antibodies through B-cell receptors

In general, it is difficult to raise novel monoclonal antibodies against relatively low-molecular weight antigen, and particularly those with high homology for the mouse protein. The optimized B-cell targeting (BCT) technique can overcome this limitation. The point of this advanced technology is the selection of sensitized B lymphocytes by the antigen through B-cell receptors (BCRs). This strict selection by specific and strong interaction between antigen and antibody enables the efficient production of monoclonal antibodies with high specificity and affinity. It also offers the condensation of sensitized target B lymphocytes to selectively generate hybridoma cells secreting desired monoclonal antibodies. In this study, several kinds of biotinylated human myoglobin (hMyo) were prepared to select sensitized B lymphocytes via BCRs. Biotinylated hMyo prepared by a 3.75- and 7.5-fold molar excess of N-hydroxysuccinimide (NHS)-biotin provided high antigenicity of 68-88%. B lymphocytes selected by these biotinylated antigens had an ELISA-positive rate >17 times higher than that with usual biotinylated antigen. Monoclonal antibodies generated by the optimized BCT technology by preselecting sensitized B lymphocytes with the target antigen were identified to specifically recognize lower antigenic epitopes in hMyo with high affinity, while this would be impossible by the polyethylene glycol (PEG) method. Furthermore, combination of these high-affinity monoclonal antibodies gave the best binding rate in an epitope binning assay. These outcomes could be attributed to the unique characteristic that BCRs on sensitized B lymphocytes themselves can select the target epitopes in the antigen. The BCRs may act as a strict sensor of B lymphocytes to precisely select the target epitopes, even though the number of immunized B lymphocytes is low.

Antigenic Cross-Reactivity Between SARS-CoV-2 S1-RBD and Its Receptor ACE2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an emerging virus responsible for the ongoing COVID-19 pandemic. SARS-CoV-2 binds to the human cell receptor angiotensin-converting enzyme 2 (ACE2) through its receptor-binding domain in the S1 subunit of the spike protein (S1-RBD). The serum levels of autoantibodies against ACE2 are significantly higher in patients with COVID-19 than in controls and are associated with disease severity. However, the mechanisms through which these anti-ACE2 antibodies are induced during SARS-CoV-2 infection are unclear. In this study, we confirmed the increase in antibodies against ACE2 in patients with COVID-19 and found a positive correlation between the amounts of antibodies against ACE2 and S1-RBD. Moreover, antibody binding to ACE2 was significantly decreased in the sera of some COVID-19 patients after preadsorption of the sera with S1-RBD, which indicated that antibodies against S1-RBD can cross-react with ACE2. To confirm this possibility, two monoclonal antibodies (mAbs 127 and 150) which could bind to both S1-RBD and ACE2 were isolated from S1-RBD-immunized mice. Measurement of the binding affinities by Biacore showed these two mAbs bind to ACE2 much weaker than binding to S1-RBD. Epitope mapping using synthetic overlapping peptides and hydrogen deuterium exchange mass spectrometry (HDX-MS) revealed that the amino acid residues P463, F464, E465, R466, D467 and E471 of S1-RBD are critical for the recognition by mAbs 127 and 150. In addition, Western blotting analysis showed that these mAbs could recognize ACE2 only in native but not denatured form, indicating the ACE2 epitopes recognized by these mAbs were conformation-dependent. The protein-protein interaction between ACE2 and the higher affinity mAb 127 was analyzed by HDX-MS and visualized by negative-stain transmission electron microscopy imaging combined with antigen-antibody docking. Together, our results suggest that ACE2-cross-reactive anti-S1-RBD antibodies can be induced during SARS-CoV-2 infection due to potential antigenic cross-reactivity between S1-RBD and its receptor ACE2.

Generation of Thermally Stable Affinity Pairs for Sensitive, Specific Immunoassays

Many point-of-care diagnostic tests rely on a pair of monoclonal antibodies that bind to two distinct epitopes of a molecule of interest. This protocol describes the identification and generation of such affinity pairs based on an easily produced small protein scaffold rcSso7d which can substitute monoclonal antibodies. These strong binding variants are identified from a large yeast display library. The approach described can be significantly faster than antibody generation and epitope binning, yielding affinity pairs synthesized in common bacterial protein synthesis strains, enabling the rapid generation of novel diagnostic tools.

Production, characterization, and epitope mapping of monoclonal antibodies of ribosomal protein S3 (rpS3)

Ribosomal protein S3 (rpS3), a member of 40S small ribosomal subunit, is a multifunctional protein with various extra-ribosomal functions including DNA repair endonuclease activity and is secreted from cancer cells. Therefore, antibodies with high specificity against rpS3 protein could be useful cancer biomarkers. In this study, polyclonal antibody (pAb) and monoclonal antibodies (mAbs) were raised against rpS3 protein and epitope mapping was performed for each antibody; the amino acid residues of rpS3 were scanned from amino acid 185 to 243 through peptide scanning to reveal the epitopes of each mAb. Results showed that pAb R2 has an epitope from amino acid 203 to 230, mAb M7 has an epitope from amino acid 213 to 221, and mAb M8 has an epitope from amino acid 197 to 219. Taken together, novel mAbs and pAb against rpS3 were raised and mapped against rpS3 with different specific epitopes.

Advancing Our Understanding of Corneal Herpes Simplex Virus-1 Immune Evasion Mechanisms and Future Therapeutics

Herpes stromal keratitis (HSK) is a disease that commonly affects the cornea and external eye and is caused by Herpes Simplex Virus type 1 (HSV-1). This virus infects approximately 66% of people worldwide; however, only a small portion of these people will develop symptoms in their lifetime. There is no cure or vaccine available for HSV-1; however, there are treatments available that aim to control the inflammation caused by the virus and prevent its recurrence. While these treatments are beneficial to those suffering with HSK, there is a need for more effective treatments to minimise the need for topical steroids, which can have harmful effects, and to prevent bouts of disease reactivation, which can lead to progressive corneal scarring and visual impairment. This review details the current understanding of HSV-1 infection and discusses potential novel treatment options including microRNAs, TLRs, mAbs, and aptamers.

Cellular Immunotherapy and the Lung

The new era of cellular immunotherapies has provided state-of-the-art and efficient strategies for the prevention and treatment of cancer and infectious diseases. Cellular immunotherapies are at the forefront of innovative medical care, including adoptive T cell therapies, cancer vaccines, NK cell therapies, and immune checkpoint inhibitors. The focus of this review is on cellular immunotherapies and their application in the lung, as respiratory diseases remain one of the main causes of death worldwide. The ongoing global pandemic has shed a new light on respiratory viruses, with a key area of concern being how to combat and control their infections. The focus of cellular immunotherapies has largely been on treating cancer and has had major successes in the past few years. However, recent preclinical and clinical studies using these immunotherapies for respiratory viral infections demonstrate promising potential. Therefore, in this review we explore the use of multiple cellular immunotherapies in treating viral respiratory infections, along with investigating several routes of administration with an emphasis on inhaled immunotherapies.

Label-Free Detection of Escherichia coli from Mixed Bacterial Cultures Using Bacteriophage T4 on Plasmonic Fiber-Optic Sensor

Consumption of water contaminated with pathogenic bacteria is a major cause of water-borne diseases. To address this challenge, we have developed a novel and sensitive sensing scheme for the rapid detection of bacteria (Escherichia coli B40) on a fiber-optic platform using bacteriophage (T4) as a bio-recognition element. The novelty of our sensing scheme is that instead of bacteriophages, bacteria (analyte) were first captured on the sensing surface and then the sensing surface was subjected to bacteriophages for specific detection of bacteria. The sensor was subjected to 100 to 10⁷ cfu/mL of E. coli B40 spiked in a lake water matrix, and the least concentration of bacteria that could be easily detected was found to be 1000 cfu/mL. The control studies were performed with nonhost bacteria Pseudomonas aeruginosa. Bacteriophage T4, being specific to its host E. coli B40, did not interact with P. aeruginosa captured on the sensing probe, giving a negligible nonspecific response. Due to the specificity of bacteriophages to its host bacteria, it is possible to use this scheme to carry out the detection of specific bacteria in a mixed sample (containing a combination of bacteria) using bacteriophages specific to it. The sensor was able to detect E. coli B40 (target bacteria) even in the presence of a very high concentration (1000 times higher) of P. aeruginosa (nontarget bacteria).

Antibody disulfide bond reduction and recovery during biopharmaceutical process development-A review

Antibody disulfide bond reduction has been a challenging issue in monoclonal antibody manufacturing. It could lead to a decrease of product purity and failure to meet the targeted product profile and/or specifications. More importantly, disulfide bond reduction could also impact drug safety and efficacy. Scientists across the industry have been examining the root causes and developing mitigation strategies to address the challenge. In recent years, with the development of high titer mammalian cell culture processes to meet the rapidly growing demand for antibody biopharmaceuticals, disulfide bond reduction has been observed more frequently. Thus, it is necessary to continue evolving the disulfide reduction mitigation strategies and developing novel approaches to maintain high product quality. Additionally, in recent years as more complex molecules (such as bispecific and trispecific antibodies) emerge, the molecular heterogeneity due to incomplete formation of the interchain disulfide bonds becomes a more imperative challenging issue. Given the disulfide reduction challenges that biotech industry is facing, in this review, we provide a comprehensive scientific summary of the root cause analysis of disulfide reduction during process development of antibody therapeutics, mitigation strategies and its potential remediated recovery based on published papers. First, this paper intends to highlight different aspects of the root cause for disulfide reduction. Secondly, to provide a broader understanding of the disulfide bond reduction in downstream process, this paper discusses disulfide bond reduction impact on product stability, associated analytical methods for disulfide bond reduction detection and characterization, process control strategies as well as their manufacturing implementation. In addition, brief perspectives on the development of future mitigation strategies are also reviewed, including platform alignment, mitigation strategy application for the emerging new modalities such as bispecific and trispecific antibodies as well as using machine learning to identify molecule susceptibility of disulfide bond reduction. The data in this review are originated from the published papers.

Matrix Metalloproteinase-9 Expression is Enhanced by Ischemia and Tissue Plasminogen Activator and Induces Hemorrhage, Disability and Mortality in Experimental Stroke

Matrix metalloproteinase-9 (MMP-9) degrades collagen and other cellular matrix proteins. After acute ischemic stroke, increased MMP-9 levels are correlated with hemorrhage, lack of reperfusion and stroke severity. Nevertheless, definitive data that MMP-9 itself causes poor outcomes in ischemic stroke are limited. In a model of experimental ischemic stroke with reperfusion, we examined whether ischemia and recombinant tissue plasminogen activator (r-tPA) therapy affected MMP-9 expression, and we used specific inhibitors to test if MMP-9 affects brain injury and recovery. After stroke, MMP-9 expression increased significantly in the ischemic vs. non-ischemic hemisphere of the brain (p < 0.001). MMP-9 expression in the ischemic, but not the non-ischemic hemisphere, was further increased by r-tPA treatment (p < 0.001). To determine whether MMP-9 expression contributed to stroke outcomes after r-tPA treatment, we tested three different antibody MMP-9 inhibitors. When compared to treatment with r-tPA and saline, treatment with r-tPA and MMP-9 antibody inhibitors significantly reduced brain hemorrhage by 11.3 to 38.6-fold (p < 0.01), brain swelling by 2.8 to 4.3-fold (p < 0.001) and brain infarction by 2.5 to 3.9-fold (p < 0.0001). Similarly, when compared to treatment with r-tPA and saline, treatment with r-tPA and an MMP-9 antibody inhibitor significantly improved neurobehavioral outcomes (p < 0.001), decreased weight loss (p < 0.001) and prolonged survival (p < 0.01). In summary, both prolonged ischemia and r-tPA selectively enhanced MMP-9 expression in the ischemic hemisphere. When administered with r-tPA, specific MMP-9 inhibitors markedly reduced brain hemorrhage, swelling, infarction, disability and death, which suggests that blocking the deleterious effects of MMP-9 may improve outcomes after ischemic stroke.

Identification of a novel epitope specific for Gp85 protein of avian leukosis virus subgroup K

During the past two decades, avian leukosis virus (ALV) caused tremendous economic losses to poultry industry in China. ALV-K as a newly found subgroup in recent years, which made the control and eradication of ALV more difficult as they were originated from the recombination of different subgroups. To date, specific rapid detection methods refer to ALV-K are still missing. Gp85 is the main structural protein of the virus, which mediates the invasion of host cells by the virus and determinates the classification of subgroups. In this study, we prepared a monoclonal antibody (Mab) named Km3 against Gp85 of ALV-K. Immunofluorescence assay showed that Km3 specifically recognized the strains of ALV-K rather than the strains of ALV-A or ALV-J. To explain the subgroups specificity of Km3, the epitope cognized by the Mab was identified by Western blotting using 15 overlapping fragments spanning the Gp85. Finally, the peptide ¹²⁹AFGPRSIDTLSDWSRPQ¹⁴⁵ was identified as the minimal linear epitope recognized by Km3. Alignment of Gp85 from different subgroups showed that the epitope was highly conserved among ALV-K strains, which was quite different from that of the strains from ALV -A, -B and -J. In conclusion, the Mab Km3 may serve as a useful reagent for ALV-K detection and diagnosis in the future.

Development of Monoclonal Antibodies and Antigen-Capture ELISA for Human Parechovirus Type 3

Human parechovirus type 3 (HPeV3) is an etiologic agent of respiratory diseases, meningitis, and sepsis-like illness in both infants and adults. Monoclonal antibodies (mAbs) can be a promising diagnostic tool for antigenic diseases such as virus infection, as they offer a high specificity toward a specific viral antigen. However, to date, there is no specific mAb available for the diagnosis of HPeV3 infection. In this study, we developed and characterized mAbs specific for HPeV3 capsid protein VP0. We used cell-free, wheat germ-synthesized viral VP0 protein for immunizing BALB/c mice to generate hybridomas. From the resultant hybridoma clones, we selected nine clones producing mAbs reactive to the HPeV3-VP0 antigen, based on enzyme-linked immunosorbent assay (ELISA). Epitope mapping showed that these mAbs recognized three distinct domains in HPeV3 VP0. Six mAbs recognized HPeV3 specifically and the other three mAbs showed cross-reactivity with other HPeVs. Using the HPeV3-specific mAbs, we then developed an ELISA for viral antigen detection that could be reliably used for laboratory diagnosis of HPeV3. This ELISA system exhibited no cross-reactivity with other related viruses. Our newly developed mAbs would, thus, provide a useful set of tools for future research and ensure HPeV3-specific diagnosis.

Biosensor platforms for rapid HIV detection

Human immunodeficiency virus (HIV), a type of lentivirus (a subgroup of retrovirus), causes acquired immunodeficiency syndrome (AIDS). This pathophysiologic state destroys the immune system allowing opportunistic infections, cancer and other life-threatening diseases to thrive. Although many analytic tools including enzyme-linked immunoassay (ELISA), indirect and line immunoassay, Western blotting, radio-immunoprecipitation, nucleic acid amplification testing (NAAT) have been developed to detect HIV, recent developments in nanosensor technology have prompted its use as a novel diagnostic approach. Nanosensors provide analytical information about behavior and characteristics of particles by using biochemical reactions mediated by enzymes, immune components, cells and tissues. These reactions are transformed into decipherable signals, i.e., electrical, thermal, optical, using nano to micro scale technology. Nanosensors are capable of both quantitative and qualitative detection of HIV, are highly specific and sensitive and provide rapid reproducible results. Nanosensor technology can trace infant infection during mother-to-child transmission, the latent HIV pool and monitor anti-HIV therapy. In this chapter, we review nanosensor analytics including electrochemical, optical, piezoelectric, SERS-based lateral flow assay, microfluidic channel-based biosensors in the detection of HIV. Other techniques in combination with different biorecognition elements (aptamers, antibodies, oligonucleotides) are also discussed.

Macromolecules and Antibody-Based Drugs

Macromolecule drugs particularly antibody drugs are very powerful therapies developing rapidly in the recent 20 years, providing hopes for many patients diagnosed with "incurable" diseases in the past. They also provide more effective and less side effects for many afflicting diseases, and greatly improve the survival rate and life quality of patients. In the last two decades, the proportion of US Food and Drug Administration (FDA) approved macromolecules and antibody drugs are increasing quickly, especially after the discovery of immune checkpoints. To crown all, the 2017 Nobel prize in physiology or medicine was given to immunotherapy. In this chapter, we would like to summarize the current situation of macromolecule and antibody drugs, and what effort scientists and pharmaceutical industry have made to discover and manufacture better antibody drugs.

Beyond Epitope Binning: Directed in Vitro Selection of Complementary Pairs of Binding Proteins

Many biotechnological applications require the simultaneous binding of affinity reagents to nonoverlapping target epitopes, the most prominent example being sandwich immunoassays. Typically, affinity pairs are identified via post facto functional analysis of clones that were not selected for complementarity. Here, we developed the Rapid Affinity Pair Identification via Directed Selection (RAPIDS) process, which enables the efficient identification of affinity reagents that function together as complementary pairs, from in vitro libraries of ∼10⁹ variants. We used RAPIDS to develop highly specific affinity pairs against biomarkers of tuberculosis, Zika virus, and sepsis. Without additional trial-and-error screening, these affinity pairs exhibited utility in multiple assay formats. The RAPIDS process applies selective pressure to hundreds of thousands of potential affinity pairs to efficiently identify complementary pairs that bind to separate epitopes without binding to one another or nontargets, yielding diagnostic assays that are sensitive and specific by design.

Immunology and Immunotherapy in Critical Care: An Overview

Until recently, immunology was not a major focus of attention in the acute and critical care setting. With the evolution of immunotherapy, however-including the development of monoclonal antibodies, checkpoint inhibitors, and adoptive cellular therapies-an in-depth understanding of the immune system has become necessary to properly care for acutely ill patients. Lymphocytes (ie, T cells and B cells) play a major role in the daily functioning of the immune response. The interaction of these cells in protecting the body against infection and foreign substances is complicated and is the basis for many of the innovations in immunology and cancer treatment. This article explores basic immunology concepts, new drug categories, and adoptive cellular therapies that are at the forefront of cancer therapy.

Identification of novel B cell epitopes in the fiber protein of serotype 8 Fowl adenovirus

In recent years, hepatitis-hydropericardium syndrome (HHS) and inclusion body hepatitis (IBH) caused by fowl adenovirus (FAdV) infection have resulted in significant economic losses to the poultry industry worldwide. Epidemiological analysis revealed that serotype FAdV-8 is one of the major pathogenic FAdVs currently prevalent in domestic flocks. Although the fiber protein of FAdV plays vital roles in viral infection and pathogenesis, the B cell epitope in the fiber protein is less known. In this study, two monoclonal antibodies (mAbs) specific to fiber protein of FAdV-8, designated as 4D9 and 5F10, were prepared. Although the mAb 4D9 and 5F10 could not neutralize FAdV-8 infection, 4D9 and 5F10 showed good activities of indirect immunofluorescence, western blot and immunoprecipitation. Epitope analysis revealed that mAb 5F10 recognized 187-219aa in the fiber whereas mAb 4D9 recognized 113-149aa in the fiber. Sequence analysis showed that the epitope recognized by mAb 5F10 was conserve across serotypes FAdV-7, 8a and 8b whereas that for mAb 4D9 was only conserve in FAdV-8b. The generation of mAbs specific to fiber of FAdV-8 and the identification of the novel B cell epitopes here lay the foundation for further studying the antigenicity of the fiber and developing specific diagnosis for FAdV-8.

Generation and characterization of a novel recombinant scFv antibody specific for Campylobacter jejuni

Campylobacter jejuni is a leading cause of foodborne illness worldwide, mainly due to consumption and handling of contaminated raw chicken. Rapid detection methods for C. jejuni are vital for monitoring contamination levels in chicken products and reducing human Campylobacteriosis cases. The 'gold standard' culture-based method of Campylobacter detection takes 3-5 days and is too slow to permit effective intervention. Immuno-based methods are faster, but usually necessitate use of animals or hybridoma technology to produce antibodies; making them difficult and expensive to produce. Here, we report the generation and characterization of recombinant single-chain variable fragment (scFv) antibodies specific for C. jejuni cells, and evaluation of one scFv antibody for an immunomagnetic separation-quantitative PCR (IMS-qPCR) method to rapidly, sensitively, and specifically detect low numbers of C. jejuni. An scFv antibody phage-display library was constructed using spleen mRNA derived from a rabbit immunized with gamma-irradiated C. jejuni cells. This library was screened by surface biopanning against C. jejuni whole cells. Enriched clones were analyzed by enzyme-linked immunosorbent assay (ELISA). Two scFv antibodies that strongly and specifically recognized C. jejuni cell were expressed in Escherichia coli. Western blot analysis showed that one antibody, scFv80, was expressed as a soluble protein and retained its specific and strong binding to C. jejuni cells. This recombinant monoclonal scFv antibody was purified and used to covalently coat paramagnetic beads to be used for IMS-qPCR. The IMS-qPCR method was able to specifically and sensitively detect C. jejuni in mixed cultures within 3 h.