Human Natural Antibodies Research Articles

The characteristics of pre-existing humoral imprint determine efficacy of S. aureus vaccines and support alternative vaccine approaches

The failure of the Staphylococcus aureus (SA) IsdB vaccine trial can be explained by the recall of non-protective immune imprints from prior SA exposure. Here, we investigate natural human SA humoral imprints to understand their broader impact on SA immunizations. We show that antibody responses against SA cell-wall-associated antigens (CWAs) are non-opsonic, while antibodies against SA toxins are neutralizing. Importantly, the protective characteristics of the antibody imprints accurately predict the failure of corresponding vaccines against CWAs and support vaccination against toxins. In passive immunization platforms, natural anti-SA human antibodies reduce the efficacy of the human monoclonal antibodies suvratoxumab and tefibazumab, consistent with the results of their respective clinical trials. Strikingly, in the absence of specific humoral memory responses, active immunizations are efficacious in both naive and SA-experienced mice. Overall, our study points to a practical and predictive approach to evaluate and develop SA vaccines based on pre-existing humoral imprint characteristics.

Enzymatically-derived oligo-carrageenans interact with α-Gal antibodies and Galectin-3

Carrageenans are linear sulfated galactans synthesized in the Gigartinales, Rhodophyceae species with a varied range of biological properties that are of value to the pharmaceutical and cosmetic sectors. It is unknown how the fine structure of carrageenans dictates their capacity to affect molecular and cellular responses important to wound healing, or the ability to mitigate oxidative, hemostatic and inflammatory processes. Here we use specific endo-carrageenases, from the marine bacterium Zobellia galactanivorans, to produce enzymatically defined neo-series oligosaccharides from carrageenans with 3,6-anhydro-D-galactose on the non-reducing end. Further enzymatic modification of the oligosaccharides was done by treating with the 3,6-anhydro-D-galactosidases from the same bacterium which hydrolyze non-reducing end 3,6-anhydro-D-galactose moieties from neo-carrageenan oligosaccharides. Using the enzymatically produced oligosaccharides, we demonstrate binding to natural human serum antibodies and a monoclonal anti-αGal Ab (m86). The significant interactions with the Galα(1,3)Gal reactive antibodies produced by humans makes them potential potent inducers of complement-dependent reactions and attractive for therapeutic applications. We also demonstrate modulation of the galectin selectivity for the Gal-3 Carbohydrate Recognition Domain (CRD) relative to Gal-1 which has implications to targeting specific biological pathways regulated by the galectins.

Targeting Spike Protein: Modified Antibody for Broad-Spectrum Binding to Coronaviruses: An In Silico Study

An antibody-mediated immune response against the Spike protein is one of the potential ways to target the SARS-CoV-2 virus. The discovery of a highly effective vaccine or an antiviral drug that specifically targets the viral entry or its replication pathway, are commonly pursued as a way to combat COVID-19-like situation. The SARS-CoV-2 virus has RNA as its genetic material, which is known for its high mutation rate. This makes the efficiency and efficacy of the vaccine against it suboptimal later due to the continuous mutations in the epitope region of the virus. This was evident in the case of the spread of the Omicron (B.1.1.529) variant. Here we tested an in-silico approach towards finding an antibody that has the potential to recognise and bind against the Spike protein of the virus across most of the variants. We achieved this by altering the sequences of the VDJ region in the heavy and light chains of the natural human antibody against the Spike protein of the SARS-CoV-2 virus (Wuhan, PDB ID: 7BWJ). This was one of the first antibodies to be studied and published along with a crystal structure during mid2020, and known to have the ability to bind and neutralize the Wuhan isolate. Iterative substitutions were induced in the 7BWJ antibody sequence in different combinations. After 28 iterations, a potential antibody was found to bind across the variants with a comparatively higher docking score. This antibody also showed the potential to target the Spike protein of many members of Coronaviruses.

Phase 1 study of pritumumab in brain cancer.

2053 Background: Pritumumab, a fully human IgG1 (kappa) monoclonal antibody (mAb), was originally isolated from a patient with cervical carcinoma. This classical example of a natural human anti-cancer antibody recognizes an altered form of the cytoskeletal protein vimentin, referred to as ectodomain vimentin (EDV). EDV is an ideal target for immunotherapy as it is expressed on the surface of tumor cells and is significantly overexpressed in glioblastomas (GBM). A multi-center phase 1 study was performed to assess the safety and pharmacokinetics of Pritumumab (NCT04396717). Methods: Eligible patients included age ≥18 years, histologically confirmed diagnosis of a central nervous system cancer, and have failed prior standard therapy. Exclusion criteria included insufficient time from prior therapy characterized as less than 28 days from cytotoxic therapy, less than 14 days from non-cytotoxic investigational agent, and less than 7 days for non-cytotoxic or immunotherapy agent. Dose Escalation Schema: Five cohort arms with up to 6 patients at each dose level included Cohort 1 (1.6 mg/kg), Cohort 2 (4.8 mg/kg), Cohort 3 (8.0 mg/kg), Cohort 4 (12.0 mg/kg), and Cohort 5 (16.2 mg/kg) on weekly 3+3 dosing schedule. Dose escalation was based on the dose-limiting toxicities (DLT) encountered through Day 28 of treatment. Pharmacokinetics:Blood and CSF samples were collected for pharmacokinetic (PK) analysis both pre- and post-dose. Results: 24 patients provided informed consent and 9 were excluded for not meeting eligibility. 15 patients received the investigational agent and were evaluable for safety and efficacy analyses. 12/15 patients had a diagnosis of glioblastoma and one patient each had anaplastic astrocytoma, oligodendroglioma, and non-small lung cancer with brain metastases. 13 patients discontinued treatment due to disease progression, one due to PI discretion for an unrelated CNS infection, and one withdrew for personal reasons. One partial response showed nearly a 98.0% and 40.8% reduction in 2 tumor lesions for 17 months on study. There were no dose-limiting toxicities to this natural human IgG mAb. The most common adverse events at least possibly attributed to Pritumumab were fatigue (53.3%) and constipation (33.3%). Other rare side effects, possibly related to Pritumumab, occurred at 6.7% were nausea, joint tenderness, dehydration, hypomagnesemia, neuropathy, pruritus, scalp dryness, dry skin (face), and depression. There were no Grade 3, 4, or 5 adverse events attributed to pritumumab. Preliminary pharmacokinetic (PK) data shows volume of distribution as 38.36 mL/kg and clearance of Pritumumab as 0.1305 mL/h/kg. The half-life of Pritumumab was found to be 12.5 days. Conclusions: Single agent Pritumumab is safe up to a dose of 16.2 mg/kg every 7 days in brain tumor patients. A phase 2 study is being planned as single agent and in combination with checkpoint inhibitors in both recurrent gliomas and upfront with chemoradiation in newly diagnosed gliomas. Clinical trial information: NCT04396717 .

LEGUME INDIAN BEAN (PHASEOLUS VULGARIS) PARTIALLY PURIFIED ANTI-NUTRITIONAL PROTEIN FACTOR EXHIBIT ANTI-OXIDANT, IMMUNOMODULATORY AND ANTI-CANCER PROPERTIES

Objective: This study was aimed to access one of the hidden ANF in Indian bean and assessment of its antioxidant, immunomodulatory, antiangiogenic, and anti-cancer properties. Methods: Indian beans were processed and evaluated for the presence of ANF through HA activity. Bean-ANF was partially purified by ammonium sulfate precipitation (ASP) and dialysis. Obtained Partially Purified bean-ANF (PPb-ANF) resolved on 12% SDS-PAGE, analyzed protease digestibility. The immunogenicity of PPb-ANF was characterized by producing polyclonal antibodies and checked for the presence of natural antibodies in healthy human sera. Pharmacological studies of PPb-ANF were assessed through anti-oxidant, immunogenic, anti-angiogenic and anti-cancer assays. Results: Partially purified Bean-ANF (PPb-ANF) showed significant specific HA activity up to 150 Units/mg compared to crude extract 9.3 of Units/mg. The PPb-ANF was identified to have more than 90% homogeneity in purity with an observed M W of 30-32 kDa. PPb-ANF showed significant pepsin digestive stability up to 2 h at 37 ᵒC and appears digestive resistant. Rabbit produced anti-PPb-ANF IgG polyclonal antibody on immunization and exhibited immunogenic properties. Natural human IgG and IgE antibodies were found in the non-atopic human sera against PPb-ANF, indicative of its immunogenicity. Pharmacological studies of PPb-ANF confirmed its potent antioxidant activity. At 400 µg of PPb-ANF showed the highest around 90% DPPH activity and at 150 µg of PPb-ANF showed 89% inhibitory lipid peroxidation activity. The PPb-ANF showed 70% (3 μg) and 40% (1.5 μg) inhibitory in blood vessel density compared to control and exhibited significant anti-angiogenic activity. The PPb-ANF showed a significant (*p<0.05.) reduction in solid tumor weight upon dose-2 treatment (50 mg/kg body weight) and also increased lifespan up to 70 d compared with the control tumor model. Conclusion: PPb-ANF was identified as digestive-resistant, hemagglutinin with a molecular weight of 30-32 kDa. The protein is immunogenic and has potential antioxidant, antiangiogenic and anti-cancer properties. Further purification and mechanistic-based pharmacological characterization might explore this protein as a potential anti-cancer molecule.

Human monoclonal natural IgG antibodies can penetrate MDA-MB-231 cells and transport intracellularly paclitaxel-loaded gold nanorods

BackgroundPrevious studies of our laboratory have shown the cell penetrating ability of polyclonal human IgGs present in Intravenous Immunoglobulin (IVIg) therapeutic preparations; those IgGs possessed Natural Antibodies (NAbs) activities, namely reactivity against several structurally unrelated self and non-self antigens (polyreactivity), due to which they can enter living cells. In this work, we isolated human monoclonal IgG Abs (h-mIgGs), derived from Multiple Myeloma patients’ sera with high mIgG concentration, exhibiting polyreactivity, and studied their penetration ability in triple negative, highly aggressive, metastatic MDA-MB-231 breast cancer cell line and their potential role as intracellular carriers of paclitaxel (PTX)-loaded gold nanorods (GNRs). Materials and methodsThe isolated h-mIgGs were tested regarding purity by SDS-PAGE, monoclonality by IsoElectric Focusing electrophoresis (IEF) and polyreactivity by ELISA. The cell–penetrating ability of h-mIgGs, alone or conjugated with GNRs and GNRs loaded with PTX, were tested by immunofluorescence (IF), and their effect on apoptosis and cell viability by FACS and MTT assay, respectively. ResultsAmong six isolated h-mIgGs, five were cell-penetrating antibodies (CPAbs) showing cytoplasmic localization in living MDA-MB-231 cells, with no effect on cell viability. In comparison to unconjugated CPAbs, CPAbs conjugates exhibited significantly augmented intracytoplasmic IF signal. One out of the five CPAbs exhibited optimum characteristics as far as antibody conjugation and cell penetration performance are concerned. The selected CPAb35-GNRs-PTX conjugate displayed a significant decrease on MDA-MB-231 cell viability when compared to GNRs-PTX conjugates and PTX alone. ConclusionsMonoclonal IgG antibodies isolated from Multiple Myeloma patients’ sera can penetrate cancer cells and transport intracellularly the chemotherapeutic agent PTX conjugated to gold nanorods. Extended screening of such h-mIgGs as potential drug-carriers might be an effective approach for their exploitation in biomedicine.

Paleo-immunology of human anti-carbohydrate antibodies preventing primate extinctions.

Two human natural anti-carbohydrate antibodies appeared in critical evolutionary events that brought primates and hominins to brink of extinction. The first is the anti-Gal antibody, produced in Old-World monkeys (OWM), apes and humans. It binds the carbohydrate-antigen 'α-gal epitope' (Galα1-3Galβ1-4GlcNAc-R) on carbohydrate-chains (glycans) synthesized by non-primate mammals, lemurs and New-World monkeys (NWM). The second is anti-N-glycolylneuraminic-acid (anti-Neu5Gc) antibody binding Neu5Gc on glycans synthesized by OWM, apes and most non-primate mammals. Ancestral OWM and apes synthesized α-gal epitopes and were eliminated ~20-30 million-years-ago (mya). Only few accidentally mutated offspring lacking α-gal epitopes, produced anti-Gal and survived. Hominin-populations living ~3 mya synthesized Neu5Gc and were eliminated, but few mutated offspring that accidently lost their ability to synthesize Neu5Gc, produced natural anti-Neu5Gc antibody. These hominins survived and ultimately evolved into present-day humans. It is argued that these two near-extinction events were likely to be the result of epidemics caused by highly virulent and lethal enveloped viruses that killed parental-populations. These viruses presented α-gal epitopes or Neu5Gc synthesized in host-cells of the parental-populations. Mutated offspring survived the epidemics because they were protected from the lethal virus by the natural anti-Gal or anti-Neu5Gc antibodies they produced due to loss of immune-tolerance to α-gal epitopes or to Neu5Gc, respectively.

Mapping monoclonal anti-SARS-CoV-2 antibody repertoires against diverse coronavirus antigens.

Variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have emerged continuously, challenging the effectiveness of vaccines, diagnostics, and treatments. Moreover, the possibility of the appearance of a new betacoronavirus with high transmissibility and high fatality is reason for concern. In this study, we used a natively paired yeast display technology, combined with next-generation sequencing (NGS) and massive bioinformatic analysis to perform a comprehensive study of subdomain specificity of natural human antibodies from two convalescent donors. Using this screening technology, we mapped the cross-reactive responses of antibodies generated by the two donors against SARS-CoV-2 variants and other betacoronaviruses. We tested the neutralization potency of a set of the cross-reactive antibodies generated in this study and observed that most of the antibodies produced by these patients were non-neutralizing. We performed a comparison of the specific and non-specific antibodies by somatic hypermutation in a repertoire-scale for the two individuals and observed that the degree of somatic hypermutation was unique for each patient. The data from this study provide functional insights into cross-reactive antibodies that can assist in the development of strategies against emerging SARS-CoV-2 variants and divergent betacoronaviruses.

Examination of the Relationship between the ABO Blood Group and Susceptibility to SARS-CoV-2 Infection Risk

The ABO blood group system has been linked with multiple infectious and non-infectious diseases and disorders such as, hepatitis B, dengue haemorrhagic fever, cancer, cardiovascular diseases, hematologic disorders, metabolic diseases, malaria, etc. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is the virus that causes COVID-19 (Coronavirus disease 2019), a respiratory infectious disease that has become a global pandemic. Several reports have investigated the role of ABO blood groups in susceptibility/resistance to various infectious Diseases, and have proposed that ABO blood group polymorphism may be linked with COVID-19 susceptibility and clinical outcomes, however, the results were questionable. It has been suggested that blood type O may have a protective role against COVID-19 infection, as blood group O individuals were found COVID-19 positive in lower levels. This could emonstrate that those Individuals are less susceptible to infection, or are asymptomatic in higher proportions, or may be associated with a slightly lower risk for severe COVID-19 disease. It has been hypothesized that the mentioned association can be probably explained by the configuration of distribution of the sialic acid-containing receptors on host cell surfaces induced by ABO antigens through carbohydrate-carbohydrate interactions, that could maximize or minimize the SARS-CoV-2 virus spike protein (S) binding to the host cell. The classical viral entry through the ACE-2 receptors can be prevented by the anti-A antibodies that are produced from O and B blood group individuals. Experimental models based on cellular lines suggested a possible explanation for blood type configuration of infection showing that S protein/ACE-2-dependent adhesion to ACE 2-expressing cells was especially inhibited by natural or monoclonal human anti-A antibodies. Consequently, non-A blood groups individuals, mainly O, or B blood group, that produce anti-A antibodies, may have a lesser degree of susceptible to SARS-CoV-2 infection due to the inhibitory effects of anti-A antibodies. Therefore, it is possible that individuals with group A are more susceptible to SARS-CoV-2 infection and/or manifestation of a severe status.

Kidney transplantation from triple-knockout pigs expressing multiple human proteins in cynomolgus macaques

Porcine cells devoid of three major carbohydrate xenoantigens, αGal, Neu5GC, and SDa (TKO) exhibit markedly reduced binding of human natural antibodies. Therefore, it is anticipated that TKO pigs will be better donors for human xenotransplantation. However, previous studies on TKO pigs using old world monkeys (OWMs) have been disappointing because of higher anti‐TKO pig antibodies in OWMs than humans. Here, we show that long‐term survival of renal xenografts from TKO pigs that express additional human transgenes (hTGs) can be achieved in cynomolgus monkeys. Kidney xenografts from TKO‐hTG pigs were transplanted into eight cynomolgus recipients without pre‐screening for low anti‐pig antibody titers. Two recipients of TKO‐hTG xenografts with low expression of human complement regulatory proteins (CRPs) (TKO‐A) survived for 2 and 61 days, whereas six recipients of TKO‐hTG xenografts with high CRP expression (TKO‐B) survived for 15, 20, 71, 135, 265, and 316 days. Prolonged CD4+T cell depletion and low anti‐pig antibody titers, which were previously reported important for long‐term survival of αGal knock‐out (GTKO) xenografts, were not always required for long‐term survival of TKO‐hTG renal xenografts. This study indicates that OWMs such as cynomolgus monkeys can be used as a relevant model for clinical application of xenotransplantation using TKO pigs.

165TiP A first-in-human phase I study of FS222, a CD137/PD-L1 tetravalent bispecific antibody, in patients with advanced malignancies

Checkpoint Inhibitor (CPI) therapy is standard of care in a range of tumor types but many patients fail to gain long term clinical benefit. Agonist antibodies targeting the T cell costimulatory receptor CD137 (4-1BB) have shown immune-stimulatory effects, but hepatotoxicity significantly hindered development. FS222, a novel tetravalent bispecific antibody, incorporates two CD137 binding sites in the Fc-region (Fcab) and anti-PD-L1 Fabs in a natural human IgG1 antibody with silenced FcyR activity.

1033TiP A first-in-human phase I study of FS120, an OX40/CD137 tetravalent bispecific antibody, in patients with advanced malignancies

In early clinical studies, agonistic antibodies targeting the T-cell costimulatory receptors OX40 and CD137 have shown immune-stimulatory effects. Dose-limiting hepatotoxicity significantly hindered further development of CD137 monotherapies. FS120 is a novel tetravalent bispecific antibody incorporating OX40 binding into the Fc-region (termed an Fcab) and CD137 Fabs in a natural human IgG1 antibody and with silenced FcyR activity for reduced toxicity, as shown in preclinical safety studies. FS120 crosslinks and clusters the receptors eliciting a robust immune stimulation and activity in mouse tumor models, independent of FcyR crosslinking (Gaspar et al 2020, Cancer Immunology Research doi: 10.1158/2326-6066).

Mixed xenogeneic porcine chimerism tolerizes human anti-pig natural antibody-producing cells in a humanized mouse model.

A major obstacle to the success of organ transplantation from pigs to humans, necessitated by the shortage of human organs, is robust humoral immune rejection by pig-reactive human antibodies. Mixed xenogeneic hematopoietic chimerism induces xenoreactive B cell tolerance in rodents, but whether mixed pig/human chimerism could induce tolerance of human B cells to pig xenoantigens is unknown. We investigated this question using a humanized mouse model in which durable mixed (pig-human) xenogeneic chimerism can be established. Human natural anti-pig cytotoxic antibodies, predominantly IgM, are detectable in non-chimeric humanized mouse serum, and pig-reactive antibodies were reduced in mixed chimeric versus non-chimeric humanized mice. This difference required persistent mixed chimerism and was not due to the adsorption of antibodies on pig cells in vivo. Furthermore, human B cells from spleens of mixed chimeric mice produced lower levels of anti-pig antibodies when stimulated in vitro compared with those from non-chimeric mice. Our findings demonstrate that mixed chimerism reduces human natural antibodies to pig xenoantigens, providing the first in vivo evidence of human B cell tolerance induction by mixed xenogeneic chimerism and supporting further evaluation of this approach for inducing human B cell tolerance to xenografts.

Antibody heavy chain CDR3 length-dependent usage of human IGHJ4 and IGHJ6 germline genes.

Therapeutic antibody discovery using synthetic diversity has been proved productive, especially for target proteins not suitable for traditional animal immunization-based antibody discovery approaches. Recently, many lines of evidences suggest that the quality of synthetic diversity design limits the development success of synthetic antibody hits. The aim of our study is to understand the quality limitation and to properly address the challenges with a better design. Using VH3–23 as a model framework, we observed and quantitatively mapped CDR-H3 loop length-dependent usage of human IGHJ4 and IGHJ6 germline genes in the natural human immune repertoire. Skewed usage of DH2-JH6 and DH3-JH6 rearrangements was quantitatively determined in a CDR-H3 length-dependent manner in natural human antibodies with long CDR-H3 loops. Structural modeling suggests choices of JH help to stabilize antibody CDR-H3 loop and JH only partially contributes to the paratope. Our observations shed light on the design of next-generation synthetic diversity with improved probability of success.

Association between ABO blood types and coronavirus disease 2019 (COVID-19), genetic associations, and underlying molecular mechanisms: a literature review of 23 studies.

An association of various blood types and the 2019 novel coronavirus disease (COVID-19) has been found in a number of publications. The aim of this literature review is to summarize key findings related to ABO blood types and COVID-19 infection rate, symptom presentation, and outcome. Summarized findings include associations between ABO blood type and higher infection susceptibility, intubation duration, and severe outcomes, including death. The literature suggests that blood type O may serve as a protective factor, as individuals with blood type O are found COVID-19 positive at far lower rates. This could suggest that blood type O individuals are less susceptible to infection, or that they are asymptomatic at higher rates and therefore do not seek out testing. We also discuss genetic associations and potential molecular mechanisms that drive the relationship between blood type and COVID-19. Studies have found a strong association between a locus on a specific gene cluster on chromosome three (chr3p21.31) and outcome severity, such as respiratory failure. Cellular models have suggested an explanation for blood type modulation of infection, evidencing that spike protein/Angiotensin-converting enzyme 2 (ACE2)-dependent adhesion to ACE2-expressing cell lines was specifically inhibited by monoclonal or natural human anti-A antibodies, so individuals with non-A blood types, specifically O, or B blood types, which produce anti-A antibodies, may be less susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection due to the inhibitory effects of anti-A antibodies.

High neutralizing potency of swine glyco-humanized polyclonal antibodies against SARS-CoV-2.

Heterologous polyclonal antibodies might represent an alternative to the use of convalescent plasma or monoclonal antibodies (mAbs) in coronavirus disease (COVID‐19) by targeting multiple antigen epitopes. However, heterologous antibodies trigger human natural xenogeneic antibody responses particularly directed against animal‐type carbohydrates, mainly the N‐glycolyl form of the neuraminic acid (Neu5Gc) and the α1,3‐galactose, potentially leading to serum sickness or allergy. Here, we immunized cytidine monophosphate‐N‐acetylneuraminic acid hydroxylase and α1,3‐galactosyl‐transferase (GGTA1) double KO pigs with the Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) spike receptor binding domain to produce glyco‐humanized polyclonal neutralizing antibodies lacking Neu5Gc and α1,3‐galactose epitopes. Animals rapidly developed a hyperimmune response with anti‐SARS‐CoV‐2 end‐titers binding dilutions over one to a million and end‐titers neutralizing dilutions of 1:10 000. The IgG fraction purified and formulated following clinical Good Manufacturing Practices, named XAV‐19, neutralized spike/angiotensin converting enzyme‐2 interaction at a concentration <1 μg/mL, and inhibited infection of human cells by SARS‐CoV‐2 in cytopathic assays. We also found that pig GH‐pAb Fc domains fail to interact with human Fc receptors, thereby avoiding macrophage‐dependent exacerbated inflammatory responses and a possible antibody‐dependent enhancement. These data and the accumulating safety advantages of using GH‐pAbs in humans warrant clinical assessment of XAV‐19 against COVID‐19.

Dissociation of the respiratory syncytial virus F protein-specific human IgG, IgA and IgM response

Human respiratory syncytial virus (RSV) is one of the most important causes of severe respiratory tract infections in early childhood. The only prophylactic protection is the neutralizing antibody, palivizumab, which targets a conformational epitope of the RSV fusion (F) protein. The F protein is generated as a F0 precursor containing two furin cleavage sites allowing excision of the P27 fragment and then gives rise to a fusion-competent version consisting of the N-terminal F2 subunit and the a C-terminal F1 subunits linked by two disulphide bonds. To investigate natural human F-specific antibody responses, F2 conferring the species-specificity of RSV, was expressed in Escherichia coli. Furthermore, the F0 protein, comprising both subunits F2 and F1, was expressed as palivizumab-reactive glycoprotein in baculovirus-infected insect cells. Six overlapping F2-derived peptides lacking secondary structure were synthesized. The analysis of IgG, IgA and IgM responses of adult subjects to native versions and denatured forms of F2 and F0 and to unfolded F2-derived peptides revealed that mainly non-conformational F epitopes, some of which represented cryptic epitopes which are not exposed on the proteins were recognized. Furthermore, we found a dissociation of IgG, IgA and IgM antibody responses to F epitopes with F2 being a major target for the F-specific IgM response. The scattered and dissociated immune response to F may explain why the natural RSV-specific antibody response is only partially protective underlining the need for vaccines focusing human antibody responses towards neutralizing RSV epitopes.

Advances in immortalization of human B cells

With the advantages of low immunogenicity and long half-life, human monoclonal antibody has become an indispensable biological agent in vivo. Immortalization of human B cells is a potential and effective method to obtain natural human antibody library, which can provide a rich source for the preparation of human monoclonal antibodies. As there are urgent problems to be solved in each platform, the preparation of antibodies based on human B cell immortalization is still limited to the laboratory research stage. At present, there is a lack of a systematic review to clarify the advantages and disadvantages of the existing human B cell immortalization antibody preparation platform and its feasibility analysis. This paper reviews the research on the preparation of human monoclonal antibody based on human B cells immortalization, and describes an in vitro cell culture method, in which hCD40L vesicles are used instead of feeder cells, in order to provide references for the further development of human monoclonal antibody preparation technology.

Application of CLN-IgG/Pritumumab against COVID-19 Infectivity from the Aspect of Tumor-PIVIEMT Scheme

The touch/tactile sensor PIEZO1/2 and vimentin network is the critical conduit for COVID-19 virus infectivity. Coordination of PIEZO1/2 and vimentin network in regard to EMT/MET which is actual accordance of PIVEMT is critical for stem cell sustenance and wound healing of the injured cells and tissues in inflammation. On the contrary PIVIEMT discordance, deteriorated PIEZO1/2-Vimentin network, provokes pathogenic symptoms such as severe autoimmunopathies. From this aspect imminent treatment is necessary to recuperate the patients from onset of pathogens and/or neoplasms by use of chaperonic antibody that is able to restore/resile the pathogenic PIVIEMT as seen in the clinical trials against brain tumor patients with repetitive administration of the natural human monoclonal antibody CLN-IgG/Pritumumab. Targeting the virus conduit with the chaperonic antibody is highly expected for not only shutting down the virus infectivity but also augmentation of the antibody-directed vaccination against virus propagation.

Synthesis of blood group A and B (type 2) tetrasaccharides. A strategy with fucosylation at the last stage

The traditionally used strategy for the synthesis of blood group A and B tetrasaccharides includes 2′-O-fucosylation of lactosamine followed by insertion of an α1-3 linked N-acetylgalactosamine or a galactose moiety. Here, we report the synthesis of 3-aminopropyl glycosides of A (type 2) and B (type 2) tetrasaccharides via an alternative sequence, i.e. α-galactosaminylation (or α-galactosylation) followed by α-fucosylation. This strategy allows us to synthesize fucose-free trisaccharides GalNAcα1-3Galβ1-4GlcNAc and Galα1-3Galβ1-4GlcNAc, which are promising targets for immunotherapy utilising human natural antibodies against the trisaccharides. The key stage in this scheme was the selective chloroacetylation of the 2′-OH group of βGal in the intermediate trisaccharides having the second (3-OH) unprotected group.The protocol is suitable for multigram syntheses and its further scaling up.