There are hundreds of coronaviruses, most of which circulate among animals, yet there are seven types that infect humans. Three of them can cause severe acute respiratory illness-SARS-CoV, SARS-CoV-2, and MERS-CoV. Other HCoV-229E, HCoV-OC43, HCoV-NL63, and HCoV-HKU1 usually cause only mild to moderate upper respiratory tract infections. These four coronaviruses are called seasonal, because they are continuously circulating among human population and are responsible for up to 30% of all respiratory tract infections. Genetically, these low-pathogenic types are related to SARS-CoV-2. That is why questions concerning the cross-reactivity and cross-neutralization between antibodies against different types of coronaviruses have been raised. We addressed these questions by using enzyme-linked immunosorbent assays and targeted next-generation sequencing (NGS).
We established the upper respiratory infection etiology for three patients who had been vaccinated with Sputnik V and tested positive on anti-SARS-CoV-2 antibodies. The symptoms included sore throat, nasal congestion, and myalgia. Their blood serum was analyzed for anti-SARS-CoV-2 antibodies in dynamics: before vaccination, and after the first and second dose of the vaccine. After the second dose, all patients were positive for IgG antibodies against SARS-CoV-2. The targeted NGS panel sequencing data analysis showed that these patients were infected with common coronavirus HCoV-OC43. These results suggest that S protein-targeted vaccine-induced antibodies against SARS-CoV-2 are not protective against seasonal coronavirus HCoV-OC43.
A universal in silico V(D)J recombination strategy for developing humanized monoclonal antibodies
Background: Humanization of mouse monoclonal antibodies (mAbs) is crucial for reducing their immunogenicity in humans. However, humanized mAbs often lose their binding affinities. Therefore, an in silico humanization method that can prevent the loss of the binding affinity of mAbs is needed.
Methods: We developed an in silico V(D)J recombination platform in which we used V(D)J human germline gene sequences to design five humanized candidates of anti-tumor necrosis factor (TNF)-α mAbs (C1-C5) by using different human germline templates. The candidates were subjected to molecular dynamics simulation. In addition, the structural similarities of their complementarity-determining regions (CDRs) to those of original mouse mAbs were estimated to derive the weighted interatomic root mean squared deviation (wRMSDi) value. Subsequently, the correlation of the derived wRMSDi value with the half maximal effective concentration (EC50) and the binding affinity (KD) of the humanized anti-TNF-α candidates was examined. To confirm whether our in silico estimation method can be used for other humanized mAbs, we tested our method using the anti-epidermal growth factor receptor (EGFR) a4.6.1, anti-glypican-3 (GPC3) YP9.1 and anti-α4β1 integrin HP1/2L mAbs.
Results: The R2 value for the correlation between the wRMSDi and log(EC50) of the recombinant Remicade and those of the humanized anti-TNF-α candidates was 0.901, and the R2 value for the correlation between wRMSDi and log(KD) was 0.9921. The results indicated that our in silico V(D)J recombination platform could predict the binding affinity of humanized candidates and successfully identify the high-affinity humanized anti-TNF-α antibody (Ab) C1 with a binding affinity similar to that of the parental chimeric mAb (5.13 × 10-10). For the anti-EGFR a4.6.1, anti-GPC3 YP9.1, and anti-α4β1 integrin HP1/2L mAbs, the wRMSDi and log(EC50) exhibited strong correlations (R2 = 0.9908, 0.9999, and 0.8907, respectively).
Conclusions: Our in silico V(D)J recombination platform can facilitate the development of humanized mAbs with low immunogenicity and high binding affinities. This platform can directly transform numerous mAbs with therapeutic potential to humanized or even human therapeutic Abs for clinical use.
Longitudinal Study after Sputnik V Vaccination Shows Durable SARS-CoV-2 Neutralizing Antibodies and Reduced Viral Variant Escape to Neutralization over Time
- Recent studies have shown a temporal increase in the neutralizing antibody potency and breadth to SARS-CoV-2 variants in coronavirus disease 2019 (COVID-19) convalescent individuals. Here, we examined longitudinal antibody responses and viral neutralizing capacity to the B.1 lineage virus (Wuhan related), to variants of concern (VOC; Alpha, Beta, Gamma, and Delta), and to a local variant of interest (VOI; Lambda) in volunteers receiving the Sputnik V vaccine in Argentina. Longitudinal serum samples (N = 536) collected from 118 volunteers obtained between January and October 2021 were used.
- The analysis indicates that while anti-spike IgG levels significantly wane over time, the neutralizing capacity for the Wuhan-related lineages of SARS-CoV-2 and VOC is maintained within 6 months of vaccination. In addition, an improved antibody cross-neutralizing ability for circulating variants of concern (Beta and Gamma) was observed over time postvaccination. The viral variants that displayed higher escape to neutralizing antibodies with respect to the original virus (Beta and Gamma variants) were the ones showing the largest increase in susceptibility to neutralization over time after vaccination.
- Our observations indicate that serum neutralizing antibodies are maintained for at least 6 months and show a reduction of VOC escape to neutralizing antibodies over time after vaccination. IMPORTANCE Vaccines have been produced in record time for SARS-CoV-2, offering the possibility of halting the global pandemic. However, inequalities in vaccine accessibility in different regions of the world create a need to increase international cooperation. Sputnik V is a recombinant adenovirus-based vaccine that has been widely used in Argentina and other developing countries, but limited information is available about its elicited immune responses.
- Here, we examined longitudinal antibody levels and viral neutralizing capacity elicited by Sputnik V vaccination. Using a cohort of 118 volunteers, we found that while anti-spike antibodies wane over time, the neutralizing capacity to viral variants of concern and local variants of interest is maintained within 4 months of vaccination. In addition, we observed an increased cross-neutralization activity over time for the Beta and Gamma variants. This study provides valuable information about the immune response generated by a vaccine platform used in many parts of the world.
In Vitro and In Vivo Fluorescence Imaging of Antibody-Drug Conjugate-Induced Tumor Apoptosis Using Annexin V-EGFP Conjugated Quantum Dots
Antibody-drug conjugates (ADCs) are conjugates of a monoclonal antibody and a cytotoxic drug that induce tumor apoptosis. The evaluation of ADC-induced tumor apoptosis is crucial for the development of ADCs for cancer therapy. To evaluate the efficacy of ADCs, we present in vitro and in vivo fluorescence imaging techniques for ADC-induced tumor apoptosis using annexin V-EGFP (EGFP: enhanced green fluorescent protein) conjugated quantum dots (annexin V-EGFP-QDs).
This probe emits visible (VIS) and near-infrared (NIR) dual fluorescence at 515 nm (EGFP emission) and 850 nm (QD emission), which can be used for the detection of tumor apoptosis at the cellular and whole-body levels. By using annexin V-EGFP-QDs, we achieved VIS and NIR fluorescence imaging of human epidermal growth factor receptor 2-positive breast tumor apoptosis induced by an ADC, Kadcyla (trastuzumab emtansine). The results show that the in vitro and in vivo fluorescence imaging of ADC-induced tumor apoptosis using annexin V-EGFP-QDs is a useful tool to evaluate the efficacy of ADCs for cancer therapy.
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Cathepsin V (Cathepsin V) Antibody |
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| 20-abx009373 | Abbexa |
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Cathepsin V (Cathepsin V) Antibody |
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LDH V antibody |
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| 35477 | SAB | 100ul | 479 EUR |
GH-V Antibody |
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GH-V Antibody |
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| MBS9405840-01mL | MyBiosource | 0.1mL | 420 EUR |
GH-V Antibody |
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| MBS9405840-5x01mL | MyBiosource | 5x0.1mL | 1740 EUR |
GnT-V Antibody |
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| abx037915-100ug | Abbexa | 100 ug | 469.2 EUR |
GnT-V Antibody |
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| E300982 | EnoGene | 100ug/200ul | 275 EUR |
GnT-V Antibody |
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GnT-V Antibody |
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GnT-V Antibody |
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GnT-V Antibody |
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| MBS854856-01mLAF405S | MyBiosource | 0.1mL(AF405S) | 565 EUR |
GnT-V Antibody |
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| MBS854856-01mLAF610 | MyBiosource | 0.1mL(AF610) | 565 EUR |
One-step immunoassay for food allergens based on screened mimotopes from autodisplayed F V–antibody library
- One-step immunoassay detects a target analyte simply by mixing a sample with a reagent solution without any washing steps. Herein, we present a one-step immunoassay that uses a peptide mimicking a target analyte (mimotope). The key idea of this strategy is that the mimotopes are screened from an autodisplayed FV-antibody library using monoclonal antibodies against target analytes. The monoclonal antibodies are bound to fluorescence-labeled mimotopes, which are quantitatively released into the solution when the target analytes are bound to the monoclonal antibodies.
- Thus, the target analyte is detected without any washing steps. For the mimotope screening, an FV-antibody library was exhibited on the outer membrane of E. coli with a diversity of >106 clones/library using autodisplay technology. The targeted clones were screened from the autodisplayed FV-antibody library using magnetic beads with immobilized monoclonal antibodies against food allergens.
- The analysis of binding properties of a control strain with mutant FV -antibodies composed of only CDR1 and CDR2 demonstrated that the CDR3 regions of the screened FV-antibodies showed binding affinity to food allergens. The CDR3 regions were synthesized into peptides as mimotopes for the corresponding food allergens (mackerel, peanuts, and pig fat). One-step immunoassays for food allergens were demonstrated using mimotopes against mackerel, peanut, and pig fat without any washing steps in solution without immobilization of antibodies to a solid support.