Shock and Temperature Monitoring During Transport of Immunoglobulins from a Hospital to Patients' Homes: A Pilot Study

Transport of biopharmaceuticals from a hospital to a patient's home is scarcely researched but it is essential to investigate the effects of such transport on the stability of the drug, before home-based care can take place. In this study, transport of biopharmaceuticals in vials that are marketed as ready-to-administer from a hospital pharmacy to patients' homes was investigated. Immunoglobulin packages were tracked with 10 G and 25 G shock indicators and temperature data loggers. In the control group, immunoglobulins were transported from the hospital pharmacy to the outpatient daycare unit. During the transport process to patients' homes (n = 39), almost half of the packages were shocked with 25 G and more than half of all packages exceeded the required temperature range. Fortunately, the results found do not affect the stability of the ready-to-administer vials with immunoglobulins. However, these results indicate that the transport of biopharmaceuticals should be better controlled as not all biopharmaceuticals or formulations are so stable. Therefore, results of this pilot study provide a basis for recommendations for home-based therapy.

Biocatalytic Method for Producing an Affinity Resin for the Isolation of Immunoglobulins

Affinity chromatography is a widely used technique for antibody isolation. This article presents the successful synthesis of a novel affinity resin with a mutant form of protein A (BsrtA) immobilized on it as a ligand. The key aspect of the described process is the biocatalytic immobilization of the ligand onto the matrix using the sortase A enzyme. Moreover, we used a matrix with primary amino groups without modification, which greatly simplifies the synthesis process. The resulting resin shows a high dynamic binding capacity (up to 50 mg IgG per 1 mL of sorbent). It also demonstrates high tolerance to 0.1 M NaOH treatment and maintains its effectiveness even after 100 binding, elution, and sanitization cycles.

Addition of sodium malonate alters the morphology and increases the critical flux during tangential flow filtration of precipitated immunoglobulins

Recent studies have demonstrated that one can control the packing density, and in turn the filterability, of protein precipitates by changing the pH and buffer composition of the precipitating solution to increase the structure/order within the precipitate. The objective of this study was to examine the effect of sodium malonate, which is known to enhance protein crystallizability, on the morphology of immunoglobulin precipitates formed using a combination of ZnCl2 and polyethylene glycol. The addition of sodium malonate significantly stabilized the precipitate particles as shown by an increase in melting temperature, as determined by differential scanning calorimetry, and an increase in the enthalpy of interaction, as determined by isothermal titration calorimetry. The sodium malonate also increased the selectivity of the precipitation, significantly reducing the coprecipitation of DNA from a clarified cell culture fluid. The resulting precipitate had a greater packing density and improved filterability, enabling continuous tangential flow filtration with minimal membrane fouling relative to precipitates formed under otherwise identical conditions but in the absence of sodium malonate. These results provide important insights into strategies for controlling precipitate morphology to enhance the performance of precipitation-filtration processes for the purification of therapeutic proteins.

Deep learning insights into the architecture of the mammalian egg-sperm fusion synapse

A crucial event in sexual reproduction is when haploid sperm and egg fuse to form a new diploid organism at fertilization. In mammals, direct interaction between egg JUNO and sperm IZUMO1 mediates gamete membrane adhesion, yet their role in fusion remains enigmatic. We used AlphaFold to predict the structure of other extracellular proteins essential for fertilization to determine if they could form a complex that may mediate fusion. We first identified TMEM81, whose gene is expressed by mouse and human spermatids, as a protein having structural homologies with both IZUMO1 and another sperm molecule essential for gamete fusion, SPACA6. Using a set of proteins known to be important for fertilization and TMEM81, we then systematically searched for predicted binary interactions using an unguided approach and identified a pentameric complex involving sperm IZUMO1, SPACA6, TMEM81 and egg JUNO, CD9. This complex is structurally consistent with both the expected topology on opposing gamete membranes and the location of predicted N-glycans not modeled by AlphaFold-Multimer, suggesting that its components could organize into a synapse-like assembly at the point of fusion. Finally, the structural modeling approach described here could be more generally useful to gain insights into transient protein complexes difficult to detect experimentally.

No evidence for a direct extracellular interaction between human Fc receptor-like 3 (MAIA) and the sperm ligand IZUMO1

Fertilization involves the recognition and fusion of sperm and egg to form a previously unidentified organism. In mammals, surface molecules on the sperm and egg have central roles, and while adhesion is mediated by the IZUMO1-JUNO sperm-egg ligand-receptor pair, the molecule/s responsible for membrane fusion remain mysterious. Recently, MAIA/FCRL3 was identified as a mammalian egg receptor, which bound IZUMO1 and JUNO and might therefore have a bridging role in gamete recognition and fusion. Here, we use sensitive assays designed to detect extracellular protein binding to investigate the interactions between MAIA and both IZUMO1 and JUNO. Despite using reagents with demonstrable biochemical activity, we did not identify any direct binding between MAIA/FCRL3 and either IZUMO1 or JUNO. We also observed no fusogenic activity of MAIA/FCRL3 in a cell-based membrane fusion assay. Our findings encourage caution in further investigations on the role played by MAIA/FCRL3 in fertilization.

Efficacy evaluation of anti-DEC-IgY against antibiotic-resistant diarrhoeagenic Escherichia coli

Introduction. The rise of multi-drug-resistant bacteria poses a global threat. In 2017, the World Health Organization identified 12 antibiotic-resistant 'priority pathogens', including Enterobacteriaceae, highlighting the menace of Gram-negative bacteria. Diarrhoeagenic Escherichia coli (DEC)-induced diarrhoea is particularly problematic for travellers and infants. In contrast to other antibiotic alternatives, passive immunotherapy is showing promise by providing immediate and precise protection. However, mammalian-sourced antibodies are costly, hindering large-scale production. Egg-laying chicken-derived IgY antibodies present a cost-effective, high-yield solution, revolutionizing antibody-based therapeutics compared to mammalian IgG.Hypothesis/Gap Statement. This study hypothesized that developing anti-DEC-IgY could combat DEC infections effectively.Aim. The primary aim was to develop anti-DEC-IgY and assess its potential in DEC-induced diarrhoeal management.Method. Chickens were immunized with DEC antigens to induce an immune response. IgY antibodies were extracted from immune eggs and purified using ion-exchange column chromatography. Anti-DEC-IgY's ability to inhibit DEC growth was evaluated through growth inhibition assays. Anti-DEC-IgY's capacity to prevent E. coli adhesion was assessed using mice intestinal mucosa. In vivo experiments measured pathogen colonization reduction and infection severity reduction. P values were calculated to confirm statistical significance.Result. The antibacterial efficacy of anti-DEC-IgY by growth inhibition assay demonstrated that 25 mg ml-1 of IgY could inhibit the DEC growth. The anti-adherence-property was tested using mice intestinal mucosa and found that anti-DEC-IgY could prevent the E. coli adhesion. In vivo results suggest that 12 mg ml-1 of IgY will reduce the pathogen colonization in intestine and reduce the severity of the infection. The P values between the experimental groups confirm the statistical significance of the findings.Conclusion. The study findings suggest that IgY-based passive immunotherapy could be a potential strategy for managing the risks associated with antibiotic-resistant bacterial infections. Additionally, this study paves the way for the development of IgY-related research and applications in India.

The Structure Characteristics and Function of Non B Cell-Derived Immunoglobulin

According to classical immunology theory, immunoglobulin (Ig) is exclusively produced by differentiated B lymphocytes, which exhibit a typical tetrapeptide chain structure and are predominantly present on the surface of B cells and in bodily fluids. B-Ig is one of the critical effector molecules for humoral immune responses specifically recognising antigens and eliminating them. However, mounting evidence has demonstrated that Ig is widely expressed in non B lineage cells, especially malignant ones (referred to as non B-Ig). Interestingly, non B-Ig mainly resides in the cytoplasm and secretion, but to some extent on the cell surface. Furthermore non B-Ig not only displays a tetrapeptide chain structure but also shows free heavy chains and free light chains (FLCs). Additionally, Ig derived from non B cancer cell typically displays unique glycosylation modifications. Functionally, non B-Ig demonstrated diversity and versatility, showing antibody activity and cellular biological activity, such as promoting cell proliferation and survival, and it is implicated in cancer progression and some immune-related diseases, such as renal diseases.

Single-molecule analysis of osmolyte-mediated nanomechanical unfolding behavior of a protein domain

The small organic molecules, known as osmolytes being ubiquitously present in different cell types, affect protein folding, stability and aggregation. However, it is unknown how the osmolytes affect the nanomechanical unfolding behavior of protein domain. Here, we show the osmolyte-dependent mechanical unfolding properties of protein titin immunoglobulin-27 (I27) domain using an atomic force microscopy (AFM)-based single-molecule force spectroscopy. We found that amines and methylamines improved the mechanical stability of I27 domain, whereas polyols had no effect. Interestingly, glycine betaine (GB) or trimethylamine-N-oxide (TMAO) increased the average unfolding force of the protein domain. The kinetic parameters analyzed at single-molecule level reveal that stabilizing effect of osmolytes is due to a decrease in the unfolding rate constant of I27, which was confirmed by molecular dynamics simulations. Our study reveals different effects that diverse osmolytes have on the mechanical properties of the protein, and suggests the potential use of osmolytes in modulating the mechanical stability of proteins required for various nano-biotechnological applications.

The Force-Dependent Mechanism of an Integrin α4β7-MAdCAM-1 Interaction

The interaction between integrin α4β7 and mucosal vascular addressin cell-adhesion molecule-1 (MAdCAM-1) facilitates the adhesion of circulating lymphocytes to the surface of high endothelial venules in inflammatory bowel diseases (IBDs). Lymphocyte adhesion is a multistep cascade involving the tethering, rolling, stable adhesion, crawling, and migration of cells, with integrin α4β7 being involved in rolling and stable adhesions. Targeting the integrin α4β7-MAdCAM-1 interaction may help decrease inflammation in IBDs. This interaction is regulated by force; however, the underlying mechanism remains unknown. Here, we investigate this mechanism using a parallel plate flow chamber and atomic force microscopy. The results reveal an initial increase in the lifetime of the integrin α4β7-MAdCAM-1 interaction followed by a decrease with an increasing force. This was manifested in a two-state curve regulated via a catch-bond-slip-bond conversion regardless of Ca2+ and/or Mg2+ availability. In contrast, the mean rolling velocity of cells initially decreased and then increased with the increasing force, indicating the flow-enhanced adhesion. Longer tether lifetimes of single bonds and lower rolling velocities mediated by multiple bonds were observed in the presence of Mg2+ rather than Ca2+. Similar results were obtained when examining the adhesion to substrates co-coated with chemokine CC motif ligand 25 and MAdCAM-1, as opposed to substrates coated with MAdCAM-1 alone. In conclusion, the integrin α4β7-MAdCAM-1 interaction occurs via ion- and cytokine-dependent flow-enhanced adhesion processes and is regulated via a catch-bond mechanism.

CmHem, a hemolin-like gene identified from Cnaphalocrocis medinalis, involved in metamorphosis and baculovirus infection

Background

As a member of the immunoglobulin superfamily, hemolins play a vital role in insect development and defense against pathogens. However, the innate immune response of hemolin to baculovirus infection varies among different insects.

Methods and results

In this study, the hemolin-like gene from a Crambidae insect, Cnaphalocrocis medinalis, CmHem was cloned, and its role in insect development and baculovirus infection was analyzed. A 1,528 bp contig as potential hemolin-like gene of C. medinalis was reassembled from the transcriptome. Further, the complete hemolin sequence of C. medinalis (CmHem) was cloned and sequenced. The cDNA of CmHem was 1,515 bp in length and encoded 408 amino acids. The deduced amino acid of CmHem has relatively low identities (41.9-62.3%) to various insect hemolins. However, it contains four Ig domains similarity to other insect hemolins. The expression level of CmHem was the highest in eggs, followed by pupae and adults, and maintained a low expression level at larval stage. The synthesized siRNAs were injected into mature larvae, and the CmHem transcription decreased by 51.7%. Moreover, the abdominal somites of larvae became straightened, could not pupate normally, and then died. Infection with a baculovirus, C. medinalis granulovirus (CnmeGV), the expression levels of CmHem in the midgut and fat body of C. medinalis significantly increased at 12 and 24 h, respectively, and then soon returned to normal levels.

Conclusions

Our results suggested that hemolin may be related to the metamorphosis of C. medinalis. Exposure to baculovirus induced the phased expression of hemolin gene in the midgut and fat body of C. medinalis, indicated that hemolin involved in the immune recognition of Crambidae insects to baculovirus.

Xeno interactions between MHC-I proteins and molecular chaperones enable ligand exchange on a broad repertoire of HLA allotypes

Immunological chaperones tapasin and TAP binding protein, related (TAPBPR) play key roles in antigenic peptide optimization and quality control of nascent class I major histocompatibility complex (MHC-I) molecules. The polymorphic nature of MHC-I proteins leads to a range of allelic dependencies on chaperones for assembly and cell-surface expression, limiting chaperone-mediated peptide exchange to a restricted set of human leukocyte antigen (HLA) allotypes. Here, we demonstrate and characterize xeno interactions between a chicken TAPBPR ortholog and a complementary repertoire of HLA allotypes, relative to its human counterpart. We find that TAPBPR orthologs recognize empty MHC-I with broader allele specificity and facilitate peptide exchange by maintaining a reservoir of receptive molecules. Deep mutational scanning of human TAPBPR further identifies gain-of-function mutants, resembling the chicken sequence, which can enhance HLA-A*01:01 expression in situ and promote peptide exchange in vitro. These results highlight that polymorphic sites on MHC-I and chaperone surfaces can be engineered to manipulate their interactions, enabling chaperone-mediated peptide exchange on disease-relevant HLA alleles.

Antibody Sequence and Structure Analyses Using IMGT®: 30 Years of Immunoinformatics

IMGT^®, the international ImMunoGeneTics information system^®, http://www.imgt.org , the global reference in immunogenetics and immunoinformatics, was created in 1989 by Marie-Paule Lefranc (Université de Montpellier and CNRS) to manage the huge diversity of the antigen receptors, immunoglobulins (IG) or antibodies, and T cell receptors (TR) of the adaptive immune responses. The founding of IMGT^® marked the advent of immunoinformatics, which emerged at the interface between immunogenetics and bioinformatics. IMGT^® standardized analysis of the IG, TR, and major histocompatibility (MH) genes and proteins bridges the gap between sequences and three-dimensional (3D) structures, for all jawed vertebrates from fish to humans. This is achieved through the IMGT Scientific chart rules, based on the IMGT-ONTOLOGY axioms, and primarily CLASSIFICATION (IMGT gene and allele nomenclature) and NUMEROTATION (IMGT unique numbering and IMGT Colliers de Perles). IMGT^® comprises seven databases (IMGT/LIGM-DB for nucleotide sequences, IMGT/GENE-DB for genes and alleles, etc.), 17 tools (IMGT/V-QUEST, IMGT/JunctionAnalysis, IMGT/HighV-QUEST for NGS, etc.), and more than 20,000 Web resources. In this chapter, the focus is on the tools for amino acid sequences per domain (IMGT/DomainGapAlign and IMGT/Collier-de-Perles), and on the databases for receptors (IMGT/2Dstructure-DB and IMGT/3D-structure-DB) described per receptor, chain, and domain and, for 3D, with contact analysis, paratope, and epitope. The IMGT/mAb-DB is the query interface for monoclonal antibodies (mAb), fusion proteins for immune applications (FPIA), composite proteins for clinical applications (CPCA), and related proteins of interest (RPI) with links to IMGT^® 2D and 3D databases and to the World Health Organization (WHO) International Nonproprietary Names (INN) program lists. The chapter includes the human IG allotypes and antibody engineered variants for effector properties used in the description of therapeutical mAb.

TAPBPR employs a ligand-independent docking mechanism to chaperone MR1 molecules

Chaperones tapasin and transporter associated with antigen processing (TAP)-binding protein related (TAPBPR) associate with the major histocompatibility complex (MHC)-related protein 1 (MR1) to promote trafficking and cell surface expression. However, the binding mechanism and ligand dependency of MR1/chaperone interactions remain incompletely characterized. Here in vitro, biochemical and computational studies reveal that, unlike MHC-I, TAPBPR recognizes MR1 in a ligand-independent manner owing to the absence of major structural changes in the MR1 α2-1 helix between empty and ligand-loaded molecules. Structural characterization using paramagnetic nuclear magnetic resonance experiments combined with restrained molecular dynamics simulations reveals that TAPBPR engages conserved surfaces on MR1 to induce similar adaptations to those seen in MHC-I/TAPBPR co-crystal structures. Finally, nuclear magnetic resonance relaxation dispersion experiments using 19F-labeled diclofenac show that TAPBPR can affect the exchange kinetics of noncovalent metabolites with the MR1 groove, serving as a catalyst. Our results support a role of chaperones in stabilizing nascent MR1 molecules to enable loading of endogenous or exogenous cargo.

Novel Antibody-Peptide Binding Assay Indicates Presence of Immunoglobulins against EGFR Phospho-Site S1166 in High-Grade Glioma

We investigated the feasibility of detecting the presence of specific autoantibodies against potential tumor-associated peptide antigens by enriching these antibody-peptide complexes using Melon Gel resin and mass spectrometry. Our goal was to find tumor-associated phospho-sites that trigger immunoreactions and raise autoantibodies that are detectable in plasma of glioma patients. Such immunoglobulins can potentially be used as targets in immunotherapy. To that aim, we describe a method to detect the presence of antibodies in biological samples that are specific to selected clinically relevant peptides. The method is based on the formation of antibody-peptide complexes by mixing patient plasma with a glioblastoma multiforme (GBM) derived peptide library, enrichment of antibodies and antibody-peptide complexes, the separation of peptides after they are released from immunoglobulins by molecular weight filtration and finally mass spectrometric quantification of these peptides. As proof of concept, we successfully applied the method to dinitrophenyl (DNP)-labeled α-casein peptides mixed with anti-DNP. Further, we incubated human plasma with a phospho-peptide library and conducted targeted analysis on EGFR and GFAP phospho-peptides. As a result, immunoaffinity against phospho-peptide GSHQIS[+80]LDNPDYQQDFFPK (EGFR phospho-site S1166) was detected in high-grade glioma (HGG) patient plasma but not in healthy donor plasma. For the GFAP phospho-sites selected, such immunoaffinity was not observed.

Trans-homophilic interaction of CADM1 promotes organ infiltration of T-cell lymphoma by adhesion to vascular endothelium

The initial step of organ infiltration of malignant cells is the interaction with host vascular endothelial cells, which is often mediated by specific combinations of cell adhesion molecules. Cell adhesion molecule 1 (CADM1) is overexpressed in adult T-cell leukemia/lymphoma (ATL) and provides a cell-surface diagnostic marker. CADM1 promotes the adhesion of ATL cells to vascular endothelial cells and multiple organ infiltration in mice. However, its binding partner on host cells has not yet been identified. In this study, we show that CADM1 promotes transendothelial migration of ATL cells in addition to the adhesion to vascular endothelial cells. Moreover, CADM1 enhances liver infiltration of mouse T-cell lymphoma cells, EL4, after tail vein injection, whereas a CADM1 mutant lacking adhesive activity did not. Among the known CADM1-binding proteins expressed in primary endothelial cells, only CADM1 and CADM4 could induce morphological extension of ATL cells when plated onto glass coated with these proteins. Furthermore, CADM1-mediated liver infiltration of EL4 cells was canceled in conventional and vascular endothelium-specific Cadm1 knockout mice, whereas it was not canceled in Cadm4 knockout mice. These results suggest that CADM1 on host vascular endothelial cells is required for organ infiltration of ATL and other T-cell lymphomas expressing CADM1.

Development of Improved High-Performance Liquid Chromatography Method for the Determination of Residual Caprylic Acid in Formulations of Human Immunoglobulins

Quality control of human immunoglobulin formulations produced by caprylic acid precipitation necessitates a simple, rapid, and accurate method for determination of residual caprylic acid. A high-performance liquid chromatography method for that purpose was developed and validated. The method involves depletion of immunoglobulins, the major interfering components that produce high background noise, by precipitation with acetonitrile (1:1, v/v). Chromatographic analysis of caprylic acid, preserved in supernatant with no loss, was performed using a reverse-phase C18 column (2.1 × 150 mm, 3 μm) as a stationary phase and water with 0.05% TFA–acetonitrile (50:50, v/v) as a mobile phase at a flow rate of 0.2 mL/min and run time of 10 min. The developed method was successfully validated according to the ICH guidelines. The validation parameters confirmed that method was linear, accurate, precise, specific, and able to provide excellent separation of peaks corresponding to caprylic acid and the fraction of remaining immunoglobulins. Furthermore, a 24−1 fractional factorial design was applied in order to test the robustness of developed method. As such, the method is highly suitable for the quantification of residual caprylic acid in formulations of human immunoglobulins for therapeutic use, as demonstrated on samples produced by fractionation of convalescent anti-SARS-CoV-2 human plasma at a laboratory scale. The obtained results confirmed that the method is convenient for routine quality control.

Tilting the Balance: Therapeutic Prospects of CD83 as a Checkpoint Molecule Controlling Resolution of Inflammation

Chronic inflammatory diseases and transplant rejection represent major challenges for modern health care. Thus, identification of immune checkpoints that contribute to resolution of inflammation is key to developing novel therapeutic agents for those conditions. In recent years, the CD83 (cluster of differentiation 83) protein has emerged as an interesting potential candidate for such a "pro-resolution" therapy. This molecule occurs in a membrane-bound and a soluble isoform (mCD83 and sCD83, respectively), both of which are involved in resolution of inflammation. Originally described as a maturation marker on dendritic cells (DCs), mCD83 is also expressed by activated B and T cells as well as regulatory T cells (Tregs) and controls turnover of MHC II molecules in the thymus, and thereby positive selection of CD4+ T cells. Additionally, it serves to confine overshooting (auto-)immune responses. Consequently, animals with a conditional deletion of CD83 in DCs or regulatory T cells suffer from impaired resolution of inflammation. Pro-resolving effects of sCD83 became evident in pre-clinical autoimmune and transplantation models, where application of sCD83 reduced disease symptoms and enhanced allograft survival, respectively. Here, we summarize recent advances regarding CD83-mediated resolution of inflammatory responses, its binding partners as well as induced signaling pathways, and emphasize its therapeutic potential for future clinical trials.

Genetic diversity in the IZUMO1-JUNO protein-receptor pair involved in human reproduction

Fertilization in mammals begins with the union of egg and sperm, an event that starts a cascade of cellular processes. The molecular-level understanding of these processes can guide the development of new strategies for controlling and/or promoting fertilization, and inform researchers and medical professional on the best choice of interventions. The proteins encoded by the IZUMO1 and JUNO genes form a ligand-receptor protein pair involved in the recognition of sperm and egg. Due to their role in the fertilization process, these proteins are potential targets for the development of novel anti-contraceptive, as well as infertility treatments. Here we present a comprehensive analysis of these gene sequences, with the objective of identifying evolutionary patterns that may support their relevance as targets for preventing or improving fertility among humans. JUNO and IZUMO1 gene sequences were identified within the genomes of over 2,000 humans sequenced in the 1000 Genomes Project. The human sequences were subjected to analyses of nucleotide diversity, deviation from neutrality of genetic variation, population-based differentiation (F_ST), haplotype inference, and whole chromosome scanning for signals of positive or of balancing selection. Derived alleles were determined by comparison to archaic hominin and other primate genomes. The potential effect of common non-synonymous variants on protein-protein interaction was also assessed. IZUMO1 displays higher variability among human individuals than JUNO. Genetic differentiation between continental population pairs was within whole-genome estimates for all but the JUNO gene in the African population group with respect to the other 4 population groups (American, East Asian, South Asian, and European). Tajima’s D values demonstrated deviation from neutrality for both genes in comparison to a group of genes identified in the literature as under balancing or positive selection. Tajima’s D for IZUMO1 aligns with values calculated for genes presumed to be under balancing selection, whereas JUNO’s value aligned with genes presumed to be under positive selection. These inferences on selection are both supported by SNP density, nucleotide diversity and haplotype analysis. A JUNO haplotype carrying 3 derived alleles out of 5, one of which is a missense mutation implicated in polyspermy, was found to be significant in a population of African ancestry. Polyspermy has a disadvantageous impact on fertility and its presence in approximately 30% of the population of African ancestry may be associated to a potentially beneficial role of this haplotype. This role has not been established and may be related to a non-reproductive role of JUNO. The high degree of conservation of the JUNO sequence combined with a dominant haplotype across multiple population groups supports JUNO as a potential target for the development of contraceptive treatments. In addition to providing a detailed account of human genetic diversity across these 2 important and related genes, this study also provides a framework for large population-based studies investigating protein-protein interactions at the genome level.

Exploring the potential usefulness of IgY for antiviral therapy: A current review

Immunoglobulin yolk (IgY) is therapeutic antibodies presented in yolk eggs of birds, reptiles, and amphibians. These proteins produced by the immune system of the animal, are capable of neutralizing antigenic molecules, including viral antigens, fulfilling a role in the body defense. The specificity of these antibodies and the facility for their production, make these molecules capable of being used as tools for diagnosis and immunotherapy. Regarding this last aspect, it is common knowledge that the field of virology, is racing against time in the development of new drugs and vaccines to try to contain pandemics and local epidemics and, in counterproposal, avian antibodies are neutralizing molecules that can help in the control and spread of disease. These molecules have been explored for years and currently chicken eggs are produced in large quantities from the animal's immunization against a specific pathogen. Thus, on this subject, this review made a survey of these researches and presents a summary of all the successful cases and perspectives in the use of IgYs as tools for viral immunization.

SCIGA: Software for large-scale, single-cell immunoglobulin repertoire analysis

BACKGROUND

B-cell immunoglobulin repertoires with paired heavy and light chain can be determined by means of 10X single-cell V(D)J sequencing. Precise and quick analysis of 10X single-cell immunoglobulin repertoires remains a challenge owing to the high diversity of immunoglobulin repertoires and a lack of specialized software that can analyze such diverse data.

FINDINGS

In this study, specialized software for 10X single-cell immunoglobulin repertoire analysis was developed. SCIGA (Single-Cell Immunoglobulin Repertoire Analysis) is an easy-to-use pipeline that performs read trimming, immunoglobulin sequence assembly and annotation, heavy and light chain pairing, statistical analysis, visualization, and multiple sample integration analysis, which is all achieved by using a 1-line command. Then SCIGA was used to profile the single-cell immunoglobulin repertoires of 9 patients with coronavirus disease 2019 (COVID-19). Four neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were identified from these repertoires.

CONCLUSIONS

SCIGA provides a complete and quick analysis for 10X single-cell V(D)J sequencing datasets. It can help researchers to interpret B-cell immunoglobulin repertoires with paired heavy and light chain.

MRCKβ links Dasm1 to actin rearrangements to promote dendrite development

Proper dendrite morphogenesis and synapse formation are essential for neuronal development and function. Dasm1, a member of the immunoglobulin superfamily, is known to promote dendrite outgrowth and excitatory synapse maturation in vitro. However, the in vivo function of Dasm1 in neuronal development and the underlying mechanisms are not well understood. To learn more, Dasm1 knockout mice were constructed and employed to confirm that Dasm1 regulates dendrite arborization and spine formation in vivo. We performed a yeast two-hybrid screen using Dasm1, revealing MRCKβ as a putative partner; additional lines of evidence confirmed this interaction and identified cytoplasmic proline-rich region (823–947 aa) of Dasm1 and MRCKβ self-activated kinase domain (CC1, 410–744 aa) as necessary and sufficient for binding. Using co-immunoprecipitation assay, autophosphorylation assay, and BS3 cross-linking assay, we show that Dasm1 binding triggers a change in MRCKβ’s conformation and subsequent dimerization, resulting in autophosphorylation and activation. Activated MRCKβ in turn phosphorylates a class 2 regulatory myosin light chain, which leads to enhanced actin rearrangement, causing the dendrite outgrowth and spine formation observed before. Removal of Dasm1 in mice leads to behavioral abnormalities. Together, these results reveal a crucial molecular pathway mediating cell surface and intracellular signaling communication to regulate actin dynamics and neuronal development in the mammalian brain.

Integrative overview of antibodies against SARS-CoV-2 and their possible applications in COVID-19 prophylaxis and treatment

SARS-CoV-2 is a novel β-coronavirus that caused the COVID-19 pandemic disease, which spread rapidly, infecting more than 134 million people, and killing almost 2.9 million thus far. Based on the urgent need for therapeutic and prophylactic strategies, the identification and characterization of antibodies has been accelerated, since they have been fundamental in treating other viral diseases. Here, we summarized in an integrative manner the present understanding of the immune response and physiopathology caused by SARS-CoV-2, including the activation of the humoral immune response in SARS-CoV-2 infection and therefore, the synthesis of antibodies. Furthermore, we also discussed about the antibodies that can be generated in COVID-19 convalescent sera and their associated clinical studies, including a detailed characterization of a variety of human antibodies and identification of antibodies from other sources, which have powerful neutralizing capacities. Accordingly, the development of effective treatments to mitigate COVID-19 is expected. Finally, we reviewed the challenges faced in producing potential therapeutic antibodies and nanobodies by cell factories at an industrial level while ensuring their quality, efficacy, and safety.

Characterization and functional analysis of fibrinogen-related protein (FreP) in the black tiger shrimp, Penaeus monodon

Ficolin is classified as an immune related protein containing collagen-like and fibrinogen-related domain (FreD). In invertebrates, the functions of fibrinogen-related proteins (FrePs) are of importance to innate immunity. In this study, a FreP in the black tiger shrimp Penaeus monodon was identified and characterized. The PmFreP cDNA is 1,007 bp long with a 921 bp-open reading frame that encodes for 306 amino acids. The deduced PmFreP sequence consists of a signal peptide, an unknown region and the FreD. Phylogenetic analysis showed that PmFreP was clustered with fibrinogen-like proteins in crustaceans which was separated from vertebrate ficolin-like proteins. The deduced fibrinogen-like domain contains four conserved cysteine residues (Cys96, Cys127, Cys249, and Cys262) that are responsible for the formation of disulfide bridges. Gene expression analysis shows that Pmfrep is mainly expressed in the intestine and the expression is significantly upregulated after Vibrio harveyi and white spot syndrome virus (WSSV) challenge. Recombinant PmFreP (rPmFreP) were successfully expressed and purified, and forms a trimeric structure as judged by native-PAGE. Bacterial binding assay showed that the rPmFreD can bind and agglutinate Gram-negative and Gram-positive bacteria in the presence of calcium (Ca²⁺) ions. Moreover, the rPmFreP facilitates the clearance of V. harveyi in vivo. Overall, our results suggested that the PmFreP may serve as pattern recognition receptors implicated in shrimp innate immunity.

Siglec-15 recognition of sialoglycans on tumor cell lines can occur independently of sialyl Tn antigen expression

Siglec-15 is a conserved sialic acid-binding Ig-like lectin expressed on osteoclast progenitors, which plays an important role in osteoclast development and function. It is also expressed by tumor-associated macrophages and by some tumors, where it is thought to contribute to the immunosuppressive microenvironment. It was shown previously that engagement of macrophage-expressed Siglec-15 with tumor cells expressing its ligand, sialyl Tn (sTn), triggered production of TGF-β. In the present study, we have further investigated the interaction between Siglec-15 and sTn on tumor cells and its functional consequences. Based on binding assays with lung and breast cancer cell lines and glycan-modified cells, we failed to see evidence for recognition of sTn by Siglec-15. However, using a microarray of diverse, structurally defined glycans, we show that Siglec-15 binds with higher avidity to sialylated glycans other than sTn or related antigen sequences. In addition, we were unable to demonstrate enhanced TGF-β secretion following co-culture of Siglec-15-expressing monocytic cell lines with tumor cells expressing sTn or following Siglec-15 cross-linking with monoclonal antibodies. However, we did observe activation of the SYK/MAPK signaling pathway following antibody cross-linking of Siglec-15 that may modulate the functional activity of macrophages.

Immunoglobulin T genes in Actinopterygii

In teleost fishes, there are three immunoglobulin isotypes named immunoglobulin M (IgM), D (IgD), and T (IgT). IgT was the last to be described in teleost fishes, and it is specific to them. From recent fish genomes, we identified and studied the immunoglobulin heavy chain genes in Actinopterygii. For this analysis, a custom bioinformatics and machine learning pipeline, we call CHfinder, was developed that identifies the exons coding for the CH domains of fish immunoglobulins. Some IgT in teleost and holostean fish found from this systematic study have not been previously described. Phylogenetic analysis of the deduced amino acid sequences of the IgT CH1 exons reveals they are similar to the CH1 of IgM. This analysis also shows that the other three domains (CH2, CH3, and CH4) were not the result of recent IgM duplication processes in Actinopterygii, demonstrating that it is an immunoglobulin of earlier origin. The bioinformatics program, CHfinder, is publicly available at https://github.com/compimmuno/CHfinder.