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1.
Talanta ; 282: 126959, 2024 Sep 25.
Article in English | MEDLINE | ID: mdl-39341062

ABSTRACT

Microcolumn gel immunoassay (MGIA) has the ability to meet the requirements of clinical diagnosis due to its reliable sensitivity and accuracy. However, traditional MGIA exhibits limitations including inadequate portability, low throughput, and extended analysis time. To address these challenges, we combined MGIA with microfluidic technology, demonstrating a centrifugal microfluidic-based microcolumn gel immunoassay (µMGIA) platform for blood typing of clinical samples. Experimental results indicate that the µMGIA platform can simultaneously detect six blood group antigens in five clinical blood samples within 2 min. Notably, it offers comprehensive detection of ABO blood group antigens and Rh blood group antigens with 100 % accuracy, outperforming the traditional slide method. The integration of microfluidic technology with MGIA circumvents the constraints of traditional methods, providing a new avenue for blood typing and immunoanalysis of clinical samples.

2.
Heliyon ; 10(15): e35697, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-39170144

ABSTRACT

Colon cancer (CC) is one of the most common gastrointestinal malignancies. Effectiveness of the existing therapies is limited. Immunotherapy is a promising complementary treatment approach for CC. Major histocompatibility complex class I-related protein A and B (MICA/B) are ligands for NK cells. Shedding of MICA/B from the surface of tumor cells by cleavage of MICA/B at the membrane proxial region in MICA/B α3 structural domain is one of immune evasion strategies leading to escape of cancer cells from immunosurveillance. In this study, we generated a panel of MICA/B monoclonal antibodies (mAbs) and identified one of mAbs, mAb RDM028, that had high binding affinity to MICA/B and recognized a site on MICA/B α3 structural domain that is critically important for cleavage of MICA/B. Our study has further demonstrated that RDM028 augmented the surface expression of MICA/B on HCT-116 human CC cells by inhibiting the MICA/B shedding resulting in the enhanced cyotoxicity of NK cells against HCT-116 human CC cells and mediated anti-tumor activity in nude mouse model of colon cancer. These results indicate that mAb RDM028 could be explored for developing as an effective immuno therapy against CC by targeting the MICA/B α3 domain to promot immunosurveillance mediated by MICA/B-NKG2D interaction.

3.
Protein Eng Des Sel ; 372024 Jan 29.
Article in English | MEDLINE | ID: mdl-39141844

ABSTRACT

Antibody discovery processes are continually advancing, with an ever-increasing number of potential binding sequences being identified out of in vivo, in vitro, and in silico sources. In this work we describe a rapid system for high yield recombinant antibody (IgG and Fab) expression using Gibson assembled linear DNA fragments (GLFs). The purified recombinant antibody yields from 1 ml expression for this process are approximately five to ten-fold higher than previous methods, largely due to novel usage of protecting flanking sequences on the 5' and 3' ends of the GLF. This method is adaptable for small scale (1 ml) expression and purification for rapid evaluation of binding and activity, in addition to larger scales (30 ml) for more sensitive assays requiring milligram quantities of antibody purified over two columns (Protein A and size exclusion chromatography). When compared to plasmid-based expression, these methods provide nearly equivalent yield of high-quality material across multiple applications, allowing for reduced costs and turnaround times to enhance the antibody discovery process.


Subject(s)
Immunoglobulin Fab Fragments , Immunoglobulin G , Recombinant Proteins , Immunoglobulin G/genetics , Immunoglobulin G/chemistry , Immunoglobulin G/biosynthesis , Recombinant Proteins/genetics , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Immunoglobulin Fab Fragments/genetics , Immunoglobulin Fab Fragments/biosynthesis , Immunoglobulin Fab Fragments/chemistry , Gene Expression , Humans , Antibodies/genetics , Antibodies/chemistry
4.
Asian J Transfus Sci ; 18(1): 45-50, 2024.
Article in English | MEDLINE | ID: mdl-39036694

ABSTRACT

BACKGROUND: For the management of hemolytic disease of the fetus and newborn (HDFN), it is important to detect unexpected red cell antibody in pregnant women. We assessed the prevalence of unexpected red cell antibodies in consecutive pregnant women attending antenatal clinic (ANC). More importantly, cases with unexpected antibody causing severe anemia were followed-up for intervention (Intra-uterine transfusion {IUT}) and outcome of pregnancy (still-birth/live-healthy). AIMS AND OBJECTIVES: The study was conducted with an objective to find the prevalence of unexpected RBC antibodies in pregnant women, their specificity and to do the follow-up for IUT and outcome of pregnancy (still-birth, live-birth) in antibody positive women. MATERIALS AND METHODS: This was a prospective study from January 2021 to May 2022 at two tertiary care centres. All antenatal samples received by the laboratory were screened for unexpected red cell antibody. Whenever antibody screen was positive, antibody identification was performed. Patients, positive for unexpected antibody and anemia were followed up for any transfusion-based intervention and outcome of pregnancy. RESULTS: A total of 539 consecutive samples were worked up and among these, 10 samples (1.85%) were found to be antibody positive. The antibodies identified were Anti-D (n=6), anti-Leb (n=1), anti-M (n=1), anti-C (n=1) and anti-E (n=1).The prevalence of unexpected antibodies in Rh positive and Rh negative pregnant women was 0.83% and 10.9% respectively. Follow-up was done for all 10 cases with unexpected antibody and anemia was monitored by MCA PSV (middle cerebral artery peak systolic velocity).Two women developed severe anemia thus requiring single intrauterine transfusion (at 26 weeks and 28 weeks respectively) each, for correction of anemia. In both these cases, healthy male child was delivered. At 3-month follow-up both children were alive and healthy. CONCLUSION: The study found prevalence of unexpected RBC antibodies in pregnant women as 1.85%. The study also underlined importance of transfusion-based interventions contributing to successful outcome in couple of cases with severe anemia.

5.
MAbs ; 16(1): 2365891, 2024.
Article in English | MEDLINE | ID: mdl-38889315

ABSTRACT

Integrins are cell surface receptors that mediate the interactions of cells with their surroundings and play essential roles in cell adhesion, migration, and homeostasis. Eight of the 24 integrins bind to the tripeptide Arg-Gly-Asp (RGD) motif in their extracellular ligands, comprising the RGD-binding integrin subfamily. Despite similarity in recognizing the RGD motif and some redundancy, these integrins can selectively recognize RGD-containing ligands to fulfill specific functions in cellular processes. Antibodies against individual RGD-binding integrins are desirable for investigating their specific functions, and were selected here from a synthetic yeast-displayed Fab library. We discovered 11 antibodies that exhibit high specificity and affinity toward their target integrins, i.e. αVß3, αVß5, αVß6, αVß8, and α5ß1. Of these, six are function-blocking antibodies and contain a ligand-mimetic R(G/L/T)D motif in their CDR3 sequences. We report antibody-binding specificity, kinetics, and binding affinity for purified integrin ectodomains, as well as intact integrins on the cell surface. We further used these antibodies to reveal binding preferences of the αV subunit for its 5 ß-subunit partners: ß6 = ß8 > ß3 > ß1 = ß5.


Subject(s)
Saccharomyces cerevisiae , Humans , Saccharomyces cerevisiae/genetics , Integrin beta Chains/immunology , Integrin beta Chains/chemistry , Integrin beta Chains/metabolism , Integrin beta Chains/genetics , Integrin alphaV/immunology , Integrin alphaV/metabolism , Integrins/immunology , Integrins/metabolism , Peptide Library , Cell Surface Display Techniques , Protein Binding , Antibody Specificity
6.
Vaccines (Basel) ; 12(4)2024 Apr 17.
Article in English | MEDLINE | ID: mdl-38675808

ABSTRACT

The rapid development of vaccines is a crucial objective in modern biotechnology and molecular pharmacology. In this context, conducting research to expedite the selection of a potent immunogen is imperative. The candidate vaccine should induce the production of antibodies that can recognize the immunogenic epitopes of the target protein, resembling the ones found in recovered patients. One major challenge in vaccine development is the absence of straightforward and reliable techniques to determine the extent to which the spectrum of antibodies produced after vaccination corresponds to antibodies found after recovery. This paper describes a newly developed method to detect antibodies specific to immunogenic epitopes of the target protein in blood plasma and to compare them with antibody spectra generated post vaccination. Comparing the antibody pool generated in the human body after recovering from an infectious disease with the pool formed through vaccination can become a universal method for screening candidate vaccines. This method will enable the identification of candidate vaccines that can induce the production of antibodies similar to those generated in response to a natural infection. Implementing this approach will facilitate the rapid development of new vaccines, even when faced with a pandemic.

7.
Methods Mol Biol ; 2793: 101-112, 2024.
Article in English | MEDLINE | ID: mdl-38526726

ABSTRACT

Recent advancements in the profiling of proteomes at the single-cell level necessitate the development of quantitative and versatile platforms, particularly for analyzing rare cells like circulating tumor cells (CTCs). In this chapter, we present an integrated microfluidic chip that utilizes magnetic nanoparticles to capture single tumor cells with exceptional efficiency. This chip enables on-chip incubation and facilitates in situ analysis of cell-surface protein expression. By combining phage-based barcoding with next-generation sequencing technology, we successfully monitored changes in the expression of multiple surface markers induced by CTC adherence. This innovative platform holds significant potential for comprehensive screening of multiple surface antigens simultaneously in rare cells, offering single-cell resolution. Consequently, it will contribute valuable insights into biological heterogeneity and human disease.


Subject(s)
Microfluidic Analytical Techniques , Neoplastic Cells, Circulating , Humans , Microfluidics , Cell Separation , Proteomics , Cell Line, Tumor , Neoplastic Cells, Circulating/pathology
8.
Methods Protoc ; 7(1)2024 Feb 01.
Article in English | MEDLINE | ID: mdl-38392687

ABSTRACT

The development of monoclonal antibodies (mAbs) represents a significant milestone in both basic research and clinical applications due to their target specificity and versatility in therapeutic and diagnostic applications. The innovative strategy of mAb screening, utilizing phage display, facilitates the in vitro screening of antibodies with high affinity to target antigens. The single-chain variable fragment (scFv) is a subset of mAb derivatives, known for its high binding affinity and smaller size-just one-third of that of human IgG. This report outlines a detailed and comprehensive procedure for constructing a scFv phagemid library derived from human patients, followed by screening via phage display affinity selection. The protocol utilizes 348 primer combinations spanning the entire human antibody repertoire to minimize sequence bias and maintain library diversity during polymerase chain reaction (PCR) for scFv generation, resulting in a library size greater than 1 × 108. Furthermore, we describe a high-throughput phage display screening protocol using enzyme-linked immunosorbent assay (ELISA) to evaluate more than 1200 scFv candidates. The generation of a highly diverse scFv library, coupled with the implementation of a phage display screening methodology, is expected to provide a valuable resource for researchers in pursuit of scFvs with high affinity for target antigens, thus advancing both research and clinical endeavors.

9.
Int Immunopharmacol ; 130: 111763, 2024 Mar 30.
Article in English | MEDLINE | ID: mdl-38412674

ABSTRACT

BACKGROUND: The identification of patients with seizures of unknown etiology who would benefit from neural antibody testing necessitates effective assessment tools. The study aimed to compare the performance of the Antibody Prevalence in Epilepsy and Encephalopathy (APE2) score and the "Obvious" Indications for Neural Antibody Testing in Epilepsy or Seizures (ONES) checklist. We also intended to evaluate whether the performance of the tools varied by types of antibody. METHODS: Patients diagnosed with epilepsy, seizures, or status epilepticus of unknown etiology at West China Hospital from January 2019 to December 2021 were included. Paired serum/cerebrospinal fluid samples were analyzed for antineuronal and antiglial antibodies. The APE2 score and ONES checklist were applied, and their outcomes were compared to laboratory antibody test results. Possible false positive neuronal antibody results were excluded in sensitivity/specificity analysis reasonably. RESULTS: A total of 113 antibody-positive and 159 antibody-negative patients were enrolled in sensitivity/specificity analysis. The ONES checklist showed superior sensitivity than APE2 score (95.6 % vs.79.6 %, P < 0.001). Specificity was not statistically different (60.4 % vs. 57.9 %, P = 0.557). The negative predictive value (NPV) of ONES checklist was higher than that of APE2 score (94.8 % vs 80.7 %, P < 0.001). The positive predictive value of them was not statistically different (61.7 % vs 58.8 %, P = 0.557). APE2 score exhibited lower sensitivity for predicting LGI-Abs (52.9 % vs. 80.3 %, P = 0.022) compared to NMDAR-Abs. Similarly, ONES checklist showed lower sensitivity for LGI1-Abs than NMDAR-Abs (82.4 % vs. 100.0 %, P = 0.009). CONCLUSIONS: The ONES checklist demonstrates superior sensitivity for neural antibody positivity than APE2 score. Specificity of the two assessment tools was similar. ONES checklist performed better NPV than the APE2 score. Both assessment tools performed less well in predicting the presence of LGI1- Abs when compared to NMDAR-Abs.


Subject(s)
Brain Diseases , Epilepsy , Humans , Autoantibodies , Seizures , Epilepsy/complications , Neurons
11.
Orthop Surg ; 16(1): 111-122, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38044447

ABSTRACT

OBJECTIVE: With advancements in minimally invasive techniques, the use of spinal fusion surgery is rapidly increasing and transfusion rates are decreasing. Routine preoperative ABO/Rh blood type and antibody screening (T&S) laboratory tests may not be appropriate for all spinal fusion patients. Herein, we constructed a nomogram to assess patient transfusion risk based on various risk factors in patients undergoing spinal fusion surgery, so that preoperative T&S testing can be selectively scheduled in appropriate patients to reduce healthcare and patient costs. METHODS: Patients who underwent spinal fusion surgery between 01/2020 and 03/2023 were retrospectively examined and classified into the training (n = 3533, 70%) and validation (n = 1515, 30%) datasets. LASSO and multivariable logistic regression were used to analyze risk factors for blood transfusion. Nomogram predictive model was built according to the independent predictors and mode predictive power was validated using consistency index (C-index), Hosmer-Lemeshow (HL) test, calibration curve analysis and area under the curve (AUC) for receiver operating characteristic (ROC) curve. Bootstrap resampling was used for internal validation. Decision curve analysis (DCA) was applied to evaluate the model's performance in the clinic. RESULTS: Being female, age, BMI, admission route, critical patient, operative time, heart failure, end-stage renal disease or chronic kidney disease (ESRD or CKD), anemia, and coagulation defect were predictors of blood transfusion for spinal fusion. A prediction nomogram was developed according to a multivariate model with good discriminatory power (C-index = 0.887); Bootstrap resampling internal validation C-index was 0.883. Calibration curves showed strong matching between the predicted and actual probabilities of the training and validation sets. HL tests for the training and validation sets had p-values of 0.327 and 0.179, respectively, indicating good calibration. When applied to the training set, the following parameters were found: AUC: 0.895, 95% CI: 0.871-0.919, sensitivity 78.2%, specificity 86.7%, positive predictive value 29.4% and negative predictive value 98.2%. If the model were applied in the training set, 2911 T&S tests (82.4%) would be eliminated, equaling a RMB349,320 cost reduction. The AUC in the internal validation was: 0.879, 95% CI: 0.839-0.927, sensitivity 75.2%, specificity 88.8%, positive predictive value 34.3%, negative predictive value 97.9%, would eliminate 1276 T&S tests (84.2%), saving RMB 153,120. The DCA curve indicated good clinical application value. CONCLUSION: The nomogram based on 10 independent factors can help healthcare professionals predict the risk of transfusion for patients undergoing spinal fusion surgery to target preoperative T&S testing to appropriate patients and reduce healthcare costs.


Subject(s)
Nomograms , Spinal Fusion , Humans , Female , Male , Retrospective Studies , Hospitalization
12.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-1019932

ABSTRACT

Objective To analyze blood type unexpected antibody and disease characteristics of inpatients in a hospital,and provide a reference for optimizing precise transfusion schemes and improving clinical transfusion safety.Methods The data of unexpected antibody screening and identification in the General Hospital of Western Theater Command from January 2012 to December 2021 were collected,while information on these patient age,gender,blood transfusion history,pregnancy history and disease diagnosis were also collected.The positive rate,composition ratio and disease characteristics of unexpected antibodies were analyzed.Results The positive rate of unexpected antibody screening was 0.55%(1 736/315 456),in which females were higher than males(0.69%vs 0.44%,χ2=90.107,P<0.05),patients with a history of blood transfusion or(and)pregnancy were higher than those without a history of blood transfusion or(and)pregnancy(75.69%vs 22.81%,χ2=971.098,P<0.05),and patients aged 40~80 accounted for 72.93%(1 266/1 736).Patients diseases with unexpected antibody positive accounted for 80.41%(1 396/1 736),mainly including digestive system diseases,immune diseases of blood and hematopoietic organs,tumors,urogenital system diseases,circulatory system diseases,musculoskeletal system and connective tissue diseases.Moreover,91.88%(1 595/1 736)of the patients with anti-screening positive underwent antibody identification,in which the majority of unexpected antibodies were Rh blood group system[41.57%(663/1 595)],Lewis blood group system[11.22%(179/1 595)],and MNS blood group system[6.90%(110/1 595)].Antibody specificity was mainly characterized by anti-E[32.41%(517/1 595)],anti-Lea[10.47%(167/1 595)],and anti-M 6.08%(97/1 595).Other antibodies[35.8%(571/1 595)]were mainly no-detected specific antibodies.Conclusion The screening results of blood type unexpected antibodies and disease type analysis are of great significance for transfusion safety.Blood transfusion department should carry out precise blood transfusion matching with multiple antigens(RhCcDEe,Lea,M)for long-term transfusion patients,women,and patients with pregnancy or blood transfusion history,so as to reduce the incidence of unexpected antibodies and improve transfusion safety.

13.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-1024984

ABSTRACT

【Objective】 To investigate the differential diagnosis of 1 anti-C, e alloantibodies combined with anti-e, Jkb mimicking alloantibodies by absorption-elution test and titer integral method. 【Methods】 ABO, Rh and Kidd blood group antigens were identified by tube method. Two sets of panel cells were used for antibody screening and antibody specificity identification by saline method, polyamine method and microcolumn gel method.The antibody was further confirmed by multiple absorption-elution tests and titer integral method. RHCE and JK gene were sequenced by multiple PCR. 【Results】 Serological gene sequencing analysis showed that the ABO blood group of the patient was A type with Rh subtype ccDEE and was positive for direct antiglobulin test (DAT). Multiple absorption-elution tests and titer integral method demonstrated that the serum of the patient contained anti-C, e alloantibodies along with anti-e, Jkb mimicking autoantibodies and there were anti-e, Jkb mimicking autoantibodies on red blood cells(RBCs). According to gene sequencing analysis, there was G>C at exon 676 of the RHCE gene, and the remaining exons were not mutated, suggesting that the RHCE phenotype was ccEE. The 838 G/A heterozygote of exon 9 in JK gene, Jk blood group phenotype was Jk (a+ b+ ). Cross matched type A ccDEE and Jk(a+ b-) RBCs were transfused, and no adverse reactions occurred. 【Conclusion】 Serology combined with molecular biology to identify the phenotype of the patient′s RBCs, absorption-elution test and titer integral method to identify the antibody of the patient′s serum can detect the alloantibody type, thus providing strategies for targeted blood transfusion.

14.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-1039529

ABSTRACT

Unexpected red blood cell antibodies refer to antibodies except for anti-A and anti-B in normal ABO blood group, and are widely present in patients with pregnancy, transfusion, transplantation, injection of immunogenic substances, or autoimmune diseases, leading to difficulties in blood type identification and cross matching test, which seriously affect transfusion safety and efficacy. This consensus aims to further standardize the requirements, operating procedures and clinical significance of antibody screening, thus improving the safety and efficacy of blood transfusion.

15.
MAbs ; 15(1): 2285904, 2023.
Article in English | MEDLINE | ID: mdl-38010801

ABSTRACT

Prior research has generated a vast amount of antibody sequences, which has allowed the pre-training of language models on amino acid sequences to improve the efficiency of antibody screening and optimization. However, compared to those for proteins, there are fewer pre-trained language models available for antibody sequences. Additionally, existing pre-trained models solely rely on embedding representations using amino acids or k-mers, which do not explicitly take into account the role of secondary structure features. Here, we present a new pre-trained model called BERT2DAb. This model incorporates secondary structure information based on self-attention to learn representations of antibody sequences. Our model achieves state-of-the-art performance on three downstream tasks, including two antigen-antibody binding classification tasks (precision: 85.15%/94.86%; recall:87.41%/86.15%) and one antigen-antibody complex mutation binding free energy prediction task (Pearson correlation coefficient: 0.77). Moreover, we propose a novel method to analyze the relationship between attention weights and contact states of pairs of subsequences in tertiary structures. This enhances the interpretability of BERT2DAb. Overall, our model demonstrates strong potential for improving antibody screening and design through downstream applications.


Subject(s)
Amino Acids , Proteins , Amino Acid Sequence , Proteins/chemistry , Amino Acids/chemistry , Protein Structure, Secondary , Antibodies
16.
Vox Sang ; 118(12): 1100-1104, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37867314

ABSTRACT

BACKGROUND AND OBJECTIVES: Screening for red blood cell alloantibodies (RBC-Ab) is a critical step in ensuring blood transfusion safety performed by blood donation screening laboratories. We aim to evaluate the prevalence of the RBC-Ab among healthy blood donors. MATERIALS AND METHODS: Antibody screening of serum of all voluntary blood donors was performed as a routine immune-haematological procedure by a solid-phase method on a fully automated immunohaematology analyser. Positive sera were further investigated to identify the specificity of RBC-Ab by a commercially available red cell panel. RESULTS: Between January 2012 and December 2021, a total of 212,218 donations were screened for the presence of RBC-Ab, 74% from male donors (n = 157,898) and 26% from female donors (n = 54,320). Mean age at donation time was 32 ± 12 years. A total of 1007 donations were screened positive (0.47%), and 131 were confirmed positive for alloantibodies in their serum, yielding a prevalence of 0.06% (95% confidence interval: 0.05-0.07). Most frequent alloantibodies identified were of RH blood group system (64%), followed by anti-MNS (19%), anti-Kidd and Lewis (6% each) and anti-KEL (4%). The results showed a statistically higher prevalence of alloantibodies in women than men. Our results showed a lower prevalence as compared to the available data, which might be related to our study population. CONCLUSION: The prevalence of positive antibody screening in healthy donors in this study was found to be 0.47%, while the prevalence of alloantibodies was 0.06%. The most common alloantibodies were anti-RH1 (25%) and anti-RH3 (24%).


Subject(s)
Isoantibodies , Military Personnel , Humans , Male , Female , Young Adult , Adult , Retrospective Studies , Blood Donors , Prevalence , Erythrocytes
17.
Lab Med ; 54(6): e197-e200, 2023 Nov 02.
Article in English | MEDLINE | ID: mdl-37527552

ABSTRACT

The Rh-D negative pregnancy is commonly associated with alloimmunization against D-antigen. It can be prevented by anti-D prophylaxis in pregnant patients with negative results on antibody screening. Hence, it is essential to exclude alloantibody-D in the presence of multiple alloantibodies. Anti-G antibody is formed after exposure to G antigen in neonate RBCs. Blood-group discrepancy was noted in reverse grouping, and antibody-screening results were positive in our case individual, a 28-year old Odiya Indian woman. We performed antibody identification on serum specimens from this patient, which revealed the pattern of anti-D + anti-C antibody specificity. Blood-group discrepancy was solved using rr (ce/ce)-phenotype pooled cells for reverse grouping. We identified anti-G antibodies by themselves without anti-D and anti-C after performing sequential adsorption of serum with r'r' (Ce/Ce) and R2R2 (DcE/DcE) group-O RBCs in the mother, who had rr phenotype and primigravida designation. After completing antibody screening at the first antenatal check-up, we recommended prophylactic anti-D for the mother in any future pregnancies she may have.


Subject(s)
Isoantibodies , Rh-Hr Blood-Group System , Infant, Newborn , Humans , Female , Pregnancy , Adult , Erythrocytes , Rho(D) Immune Globulin , ABO Blood-Group System
18.
MAbs ; 15(1): 2245519, 2023.
Article in English | MEDLINE | ID: mdl-37599441

ABSTRACT

A challenge when developing therapeutic antibodies is the identification of candidates with favorable pharmacokinetics (PK) early in development. A key determinant of immunoglobulin (IgG) serum half­life in vivo is the efficiency of pH-dependent binding to the neonatal Fc receptor (FcRn). Numerous studies have proposed techniques to assess FcRn binding of IgG-based therapeutics in vitro, enabling prediction of serum half-life prior to clinical assessment. FcRn high-performance liquid chromatography (HPLC) assays FcRn binding of therapeutic IgGs across a pH gradient, allowing the correlation of IgG column retention time to the half­life of a therapeutic IgG in vivo. However, as FcRn retention time cannot be directly compared to an in vivo parameter, modifications to FcRn-HPLC are required to enable interpretation of the data within a physiological context, to provide more accurate estimations of serum half-life. This study presents an important modification to this method, FcRn-pH-HPLC, which reproducibly measures FcRn dissociation pH, allowing correlation with previously established half-lives of therapeutic antibodies. Furthermore, the influence of incorporating various antibody modifications, binding modules, and their orientations within IgGs and bispecifics on FcRn dissociation pH was evaluated using antibodies from the redirected optimized cell killing (ROCK®) platform. Target and effector antigen-binding domain sequences, their presentation format and orientation within a bispecific antibody alter FcRn retention; tested Fc domain modifications and incorporating stabilizing disulfide bonds had minimal effect. This study may inform the generation of mono-, bi- and multi-specific antibodies with tailored half-lives based on FcRn binding properties in vitro, to differentiate antibody-based therapeutic candidates with optimal developability.


Subject(s)
Antibodies, Bispecific , Humans , Infant, Newborn , Chromatography, High Pressure Liquid , Antibodies, Monoclonal/chemistry , Immunoglobulin G , Receptors, Fc , Histocompatibility Antigens Class I , Chromatography, Affinity , Hydrogen-Ion Concentration
19.
Front Cell Infect Microbiol ; 13: 1118979, 2023.
Article in English | MEDLINE | ID: mdl-37404721

ABSTRACT

Talaromycosis is a fungal infection that generally affects immunocompromised hosts and is one of the most frequent systemic mycoses in HIV patients, especially in endemic areas such as Southeast Asia. Talaromyces marneffei, the causative agent of talaromycosis, grows as a mold in the environment but adapts to the human body and host niches by transitioning from conidia to yeast-like cells. Knowledge of the human host and T. marneffei interaction has a direct impact on the diagnosis, yet studies are still lacking. The morbidity and mortality rates are high in taloromycosis patients if the diagnosis and treatments are delayed. Immunogenic proteins are excellent candidates for developing detection tools. Previously, we identified antigenic proteins that were recognized by antibodies from talaromycosis sera. Three of these identified proteins have been previously characterized in detail, while the others have not been explored. To expedite the progress of antigen discovery, the complete list of antigenic proteins and their features was fully reported in this study. Functional annotation and Gene Ontology examination revealed that these proteins showed a high association with membrane trafficking. Further bioinformatics analyses were performed to search for antigenic protein characteristics, including functional domains, critical residues, subcellular localization, secretory signals, and epitope peptide sequences. Expression profiling of these antigenic encoding genes was investigated using quantitative real-time PCR. The results demonstrated that most genes were expressed at low levels in the mold form, but were highly upregulated in the pathogenic yeast phase, consistent with the antigenic role of these genes during the human-host interaction. Most transcripts accumulated in the conidia, suggesting a role during phase transition. The collection of all antigen-encoding DNA sequences described here is freely accessible at GenBank, which could be useful for the research community to develop into biomarkers, diagnostic tests, research detection tools, and even vaccines.


Subject(s)
HIV Infections , Mycoses , Humans , Saccharomyces cerevisiae , Mycoses/diagnosis
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