Background ARTISTRY-1 is an ongoing Phase 2/3 study evaluating the safety and efficacy of once-daily oral bictegravir (BIC) + lenacapavir (LEN) in virologically suppressed (VS; HIV-1 RNA <50 copies/mL) participants on complex antiretroviral (ARV) regimens. Here, we report Week 96 extension-phase data after transition to BIC/LEN single-tablet regimen (STR). Methods Participants without known integrase strand-transfer inhibitor (INSTI) resistance were randomized (2:2:1) to BIC + LEN (75mg + 25mg or 75mg + 50mg) or stable background regimen, respectively. At the end of randomized treatment (mean of 69 weeks from baseline), participants could choose to enter the extension period and receive BIC/LEN 75/50 mg STR. Baseline resistance-associated mutations (RAMs) were evaluated from cumulative historical genotypic reports (HGRs) and Day 1 proviral DNA genotyping using a composite baseline sequence. Resistance testing was performed for confirmed virologic rebound. Results Of 128 randomized/dosed participants, 119 entered the extension period and received BIC/LEN STR for a median time of 96 weeks (range 11–109) from end of randomization to cutoff date. Baseline RAMs were common (nucleoside reverse transcriptase inhibitor 82%, non-nucleoside reverse transcriptase inhibitor 66%, protease inhibitor 47%; INSTI RAMs 9% (proviral DNA)). Two participants met criteria for resistance testing before resuppressing, with no treatment-emergent capsid or integrase RAMs. All 119 participants were suppressed at last observed visit. Conclusions Durable viral suppression was maintained for up to 96 weeks in the Phase 2 extension, with all participants in the extension phase maintaining virologic suppression and no treatment-emergent resistance to study drugs, supporting long-term virologic durability of BIC/LEN STR in VS individuals on complex ART.
Objective The objective was to evaluate the safety, pharmacokinetics and efficacy of an alternative deltoid site for CAR-LA. Design This is a prospective cohort of people living with HIV (PLWHIV) switching for intramuscular long acting cabotegravir and rilpivirine (CAR-LA). Methods Clinical and biological data were collected at baseline, month 1 (M1), month 3 (M3), and every three months thereafter, when available. Results A total of 15 patients were enrolled between August 2022 and October 2024. Of these, 11 were transgender women, 1 cisgender woman, and 3 cisgender males. The median duration of plasma HIV-1-RNA (pVL) <50 copies/mL before switching to CAR-LA was 42 months. The main criterion for selecting PLWHIV was the presence of injected silicone in the gluteal region (12 out of 15 cases). Median duration of CAR-LA was 13 months. All patients maintained a pVL<50 copies/mL at M1 and M3. No virological failure was observed in the 13 patients who were followed up to M12. One PLWHIV discontinued deltoid injections due to low plasma concentrations at M2, while another discontinued due to non-adherence which led to cabotegravir resistance at M13. Three PLWHIV reported moderate pain at the injection site, with one discontinuing treatment at M12. All CAB and RPV plasma concentrations measured after deltoid CAR-LA were comparable with those obtained following gluteal CAR-LA phase 3 studies. Conclusion Deltoïd CAR-LA seems to be a reliable and well-tolerated alternative for PLWHIV with contraindications for gluteal injections.
Background Posttransplant cytomegalovirus (PT-CMV) infection remains a challenging complication and a major cause of morbidity and mortality in transplant recipients. Methods This cross-sectional study surveyed physicians treating solid organ and hematopoietic stem cell transplantation recipients from Central and Eastern European countries. Physician-reported CMV infection prevalence in transplant recipients, treatment regimens, and unmet needs for managing patients with refractory with/without resistance (R+/R-) PT-CMV infection were assessed. Results Overall, 164 physicians completed the survey, 23.8% of whom were nephrologists. Physicians estimated that 26.4% of patients who received a transplant in the past 12 months developed PT-CMV infection, of whom 12.9% had refractory R+/R- PT-CMV infection. On average, 66.5%, 16.5%, and 4.0% of physicians’ current patients with PT-CMV infection received first-, second-, and third- or later-line treatments, respectively. Physicians considered maintenance of CMV viremia clearance (94.5%), good symptom control (94.5%), and lack of renal toxicity (93.9%) as moderately-to-extremely important treatment attributes for managing PT-CMV infection. Compared with other available treatments, more physicians indicated oral valganciclovir to have a strong-to-complete association with these treatment attributes. Overall, 63.4% of physicians indicated some level of satisfaction with conventional refractory R+/R- PT-CMV treatments. However, 54.9% of physicians reported limited experience with newly approved therapies, such as maribavir. Most physicians considered limited treatment options as a major barrier for improving patient outcomes. Conclusion Survey findings of physicians treating transplant recipients in Central and Eastern Europe suggest the need for increased awareness of newly approved therapies with better efficacy and less toxicity for refractory R+/R- PT-CMV infection.
Background: Transferrin receptor protein 1 (TfR1) plays a central role in cellular iron uptake and is frequently overexpressed in malignant tumor cells, rendering it an attractive target for tumor-directed therapy and drug delivery. Methods: A fully human single-chain variable fragment (scFv) antibody targeting TfR1, termed T8scFv, was isolated from a human scFv phage display library through three rounds of stringent biopanning and subsequently reformatted into a full-length IgG1 antibody (T8IgG1). Binding kinetics were characterized using Octet biolayer interferometry (BLI), while cellular binding and internalization were assessed by flow cytometry and immunofluorescence microscopy, respectively. T8IgG1 was further conjugated to DT3C, a recombinant truncated diphtheria toxin fusion protein, to evaluate its internalization-dependent cytotoxicity in vitro. Results: T8scFv exhibited nanomolar affinity for TfR1 (KD = 214 ± 1 nM), which was substantially enhanced following conversion to the IgG1 format (T8IgG1, KD = 18.5 ± 0.1 nM). T8IgG1 specifically recognized TfR1 on the surface of tumor cells and underwent efficient TfR1-mediated internalization. The T8IgG1-DT3C complex significantly reduced cell viability and induced apoptosis in K562 cells in vitro. Conclusions: These findings indicate that T8IgG1 is a moderate-affinity, internalizing anti-TfR1 antibody and highlight its potential as a promising candidate for TfR1-based targeted antitumor drug delivery systems.
Background/Objectives: Antibodies are a rapidly expanding field in drug discovery, but their monospecificity limits therapeutic applications, particularly in complex inflammatory diseases. Multispecific therapeutics, which combine variable regions targeting two or more antigens, offer potential advantages such as enhanced efficacy, broader target modulation, and reduced side effects. This study aimed to identify and characterize bispecific, VHH-based antibodies simultaneously targeting IL-6 and IL-17A-two key cytokines involved in autoimmune and chronic inflammatory conditions. Methods: A phage display screening was conducted using llama-derived VHH libraries to select binders against human IL-6 and IL-17A. Binding affinities of individual VHHs and assembled bispecific constructs were assessed using Bio-Layer Interferometry (BLI). Functional activity was evaluated using reporter cell lines responsive to IL-6 and IL-17A signaling. Biophysical and quality assessments of selected VHHs and bispecific antibodies were performed using the Uncle screening platform and LabChip capillary electrophoresis. Results: Several high-affinity VHH binders were identified for both IL-6 and IL-17A, and incorporated into bispecific antibody formats. The bispecific candidates exhibited simultaneous inhibition of both cytokine pathways in functional reporter assays. Biophysical characterization confirmed good stability and purity profiles for selected molecules. Conclusions: This study demonstrates the feasibility of generating stable, functional bispecific VHH-based antibodies targeting IL-6 and IL-17A. These constructs show potential as therapeutic agents for treating autoimmune and chronic inflammatory diseases by modulating multiple signaling pathways simultaneously.
Objectives: To determine the incidence and outcomes of SARS-CoV-2 infection and to evaluate seroconversion rates and quantify antibody responses to COVID-19 vaccines in two cohorts of persons living with HIV at a possible higher risk of poor outcomes (HCV coinfection and those over the age of 65 years). Methods: We included participants from two established cohorts of persons living with HIV, those who were older than 65 years of age, and those with hepatitis C (HCV) co-infection. Four hundred and seventy-one participants completed questionnaires on SARS-CoV-2 infection and COVID-19 vaccine doses and submitted peripheral blood specimens for measuring antibody levels to COVID-19 antigens, full-length spike trimer, its receptor binding domain (RBD), and nucleocapsid protein (N) at 6-month intervals up to three visits between February 2021 and December 2024. Logistic and ordinal logistic regression models evaluated predictors of seroconversion and antibody levels. Results: Overall, 51% of participants developed a SARS-CoV-2 infection, but it was mild, with only nine requiring hospital admission and no deaths. Overall, 99% of tested specimens had antibodies above threshold to either spike or RBD proteins. Specimens that did not and those with lower antibody levels had testing earlier in the pandemic, and were from participants with fewer vaccine doses, and did not have natural infection. Age, depression, comorbidity, HCV co-infection, current substance use, CD4 count, or HIV viral load were predictive of antibody level. Those with hybrid immunity had higher antibody responses. Conclusions: In cohorts of persons with HIV-HCV coinfection and those who are ageing, we observed high rates of seroconversion to COVID-19 antigens. Antibody levels were higher among those with more vaccine doses, hybrid immunity, and later in the pandemic waves. Although 51% developed a breakthrough infection, outcomes were mild with no deaths.
Systemic lupus erythematosus (SLE) is an autoimmune disease that predominantly affects women of childbearing age, and active disease during pregnancy is associated with increased maternal and fetal morbidity. Belimumab is an effective biologic therapy for active SLE; however, its use during pregnancy has long been limited by the scarcity of safety data. Recent evidence and updated international recommendations suggest that belimumab may be considered in selected cases when required to maintain maternal disease control. We report the case of a woman with SLE who experienced three consecutive pregnancies with live births between 2019 and 2024 while receiving belimumab, allowing an intra-individual comparison of different exposure strategies. During the first pregnancy, belimumab was discontinued at conception and was followed by a disease flare in late pregnancy and postpartum. In the second and third pregnancies, belimumab was continued until gestational week 20 following shared decision-making with the patient; nevertheless, disease flares occurred during the third trimester of both pregnancies. All pregnancies resulted in live births at term, with no congenital anomalies, placental insufficiency, or fetal growth restriction. One neonate from the third pregnancy developed early-onset neonatal sepsis and meningitis, which resolved completely after antibiotic treatment. All children are currently growing and developing normally. This case supports a risk-adapted approach to belimumab use during pregnancy. In selected women with SLE at high risk of disease reactivation, continuation of belimumab until mid-gestation may contribute to improved maternal disease control without evident adverse fetal outcomes.
Background/Objectives: The neonatal Fc receptor (FcRn) plays a crucial role in extending the systemic half-life of monoclonal antibodies (mAbs), but its influence on ocular distribution remains incompletely understood. This study investigated the impact of FcRn on the ocular disposition of mAbs following systemic administration in rabbits. Methods: New Zealand White rabbits received a single intravenous dose (1 mg/kg) of either wild-type trastuzumab (TS-WT) or its FcRn non-binding variant (IHH). Plasma and ocular tissues (retina, iris-ciliary body, vitreous humor, aqueous humor, cornea, conjunctiva, and tears) were collected at terminal time points up to 336 h for TS-WT and 168 h for IHH. Antibody concentrations were quantified using a validated sandwich ELISA. Pharmacokinetic parameters and antibody biodistribution coefficients (ABC) were calculated to assess the FcRn-mediated effects on ocular distribution. Results: TS-WT demonstrated 2-fold higher systemic exposure compared to IHH. The iris-ciliary body exhibited the highest absolute exposure for both antibodies, with TS-WT showing significantly higher accumulation (ABC0-168h: 14.95% vs. 8.89%). Retinal distribution remained comparable between antibodies (5.96% vs. 5.51%). Both antibodies were detectable in tears, with ABC value of ~4% reported for TS-WT. TS-WT also demonstrated markedly increased distribution in vitreous humor and tear fluid (3.5- and 5.5-fold higher ABC values, respectively) compared to IHH. The cornea (5.76% vs. 5.57%) and conjunctiva (7.71% vs. 7.21%) showed comparable relative distribution between TS-WT and IHH, while aqueous humor showed minimal differences (0.44% vs. 0.52%). Conclusions: This investigation reveals distinct tissue-specific patterns of FcRn-mediated mAb distribution within the eye. FcRn binding significantly enhanced antibody distribution in ocular tissues, such as the iris-ciliary body, and tears, with less pronounced effects on the retina, cornea, conjunctiva and aqueous humor. These findings provide mechanistic insights for optimizing mAb-based therapeutics for ocular disease and understanding the ocular toxicity of mAb-based therapeutics, such as antibody-drug conjugates.
BACKGROUND:Protein A resins are indispensable for monoclonal antibody (mAb) production, yet their condition and performance are traditionally assessed using indirect or qualitative methods. In this study, the multi-attribute method (MAM), previously applied to therapeutic protein characterization, is systematically adapted for the first time as a unified liquid chromatography-mass spectrometry (LC-MS) platform for Protein A resin analysis. METHOD:Four Cytiva Protein A resins, MabSelect™, MabSelect SuRe™, MabSelect SuRe™ LX, and MabSelect™ PrismA, were evaluated by MAM for resin identity, Protein A ligand integrity, fouling by impurities, and cleaning performance. RESULTS:MAM enables resin-specific peptide fingerprinting and quantitative monitoring of Protein A ligand post-translational modifications (PTMs), including deamidation, isomerization, and fragmentation induced by repeated clean-in-place (CIP) cycles. Comparative analysis of virgin and used resins revealed ligand degradation and fouling despite engineered alkaline stability, with MabSelect™ showing the greatest susceptibility. Importantly, residual monoclonal antibodies (mAbs) and host cell proteins (HCPs) were directly detected and quantified from the resin matrix, providing a molecular-level assessment of resin cleaning effectiveness not achievable with conventional approaches. CONCLUSIONS:This work establishes MAM as a novel, sensitive, and comprehensive strategy for Protein A resin lifecycle management, delivering actionable insight for resin selection, cleaning optimization, and downstream process development.
BACKGROUND/OBJECTIVES:Mitochondria are dynamic organelles that continuously undergo balanced cycles of fusion and division to maintain optimal function. Mitochondrial division is mediated by Dynamin-Related Protein 1 (DRP1), a cytosolic large GTPase whose phosphorylation at serine 616 (DRP1-S616Ⓟ) promotes its translocation to the outer mitochondrial membrane and organelle division. Dysregulated mitochondrial division disrupts cellular homeostasis and contributes to disease pathogenesis, including cancer. Our prior work demonstrated that the oncogene-induced mitogen-activated protein kinase (MAPK) pathway constitutively phosphorylates DRP1 at serine 616, which is essential to cellular transformation and correlates with oncogene status in patient tissues. Similarly, DRP1-S616Ⓟ is subject to pharmacologic control by targeted therapies against oncogenic MAPK signaling. METHODS:Building upon this foundation, we developed and characterized a recombinant murine monoclonal antibody (referred to as 3G11) with high specificity for human DRP1-S616Ⓟ, raised against a peptide derived from the human DRP1 sequence. RESULTS:Using diverse experimental platforms, we demonstrate the robust utility of 3G11 to detect DRP1-S616Ⓟ in melanoma cell extracts and isolated organelles. Immunofluorescence revealed that pharmacologic inhibition of oncogenic MAPK signaling reduces DRP1-S616Ⓟ levels, which correlates with mitochondrial hyperfusion, while immunohistochemistry showed that elevated DRP1-S616Ⓟ expression in human tissues correlates with BRAFV600E disease. CONCLUSIONS:3G11 is a new recombinant antibody for detecting DRP1-S616Ⓟ and supports studies of mitochondrial division in cancer. Together, these findings establish 3G11 as a specific, versatile, renewable, and cost-effective tool for studying mitochondrial division, with strong potential for clinical applications.
Data from the REPRIEVE trial have been used to study the association between treatment with abacavir and cardiovascular disease in people with HIV. Past exposure to abacavir before the trial was found to be just as risky as exposure during the trial. This calls into doubt the widely accepted hypothesis that recent exposure to abacavir increases the risk of cardiovascular disease but that risk rapidly attenuates after exposure ends. The evidence for this hypothesis is weak while evidence for an alternative hypothesis has been neglected. An alternative hypothesis is that risk from exposure to abacavir is not immediate but increases as exposure cumulates, plateauing after about three years. Confusion over the likely effect of abacavir has arisen partly because overly simplistic methods have been used to model the exposure outcome relationship in observational cohort data. Better methods are available and should be used in future to avoid misdirected research effort.
BackgroundIntravenous hyper-immune anti-cytomegalovirus immunoglobulins (CMV-IG) therapy are licensed for prophylaxis, yet their therapeutic value in established CMV disease remains poorly defined. We aimed to evaluate the clinical and virological impact of adjunctive CMV-IG in combination with standard antiviral therapy in immunocompromised patients with CMV disease, compared with standard antiviral therapy alone.MethodsWe performed a single-center retrospective case-control study at A.O.U. "Federico II" University Hospital, Naples, Italy, including consecutive immunocompromised patients with CMV disease between March 2021 and November 2024. Cases received standard antiviral therapy plus CMV-IG (100 IU kg-1 day-1 for three consecutive days). Controls received antivirals only.ResultsThirty-four patients were analyzed (15 cases, 19 controls). Thirty-day survival was 93% vs 95% (p=>0.9) and composite outcome (combination of 30-day mortality and clinical response) occurred in 93% vs 90% (p=>0.9) in cases and controls, respectively. Median time-to-virological response in days was achieved 4 vs 7 days (p=<0.001), as was median duration of antiviral therapy in days 12 vs 16 days (p=0.001) and hospitalization 14 vs 19 days (p=0.004) in cases and controls, respectively. Adverse-event rates were low and comparable in the 2 groups.ConclusionsIn this real-world cohort, adjunctive CMV-IG did not affect mortality, but was associated with faster virological clearance and shorter antiviral and hospital courses, without additional toxicity.
Background/Objectives: The SARS-CoV-2 virus frequently undergoes mutations to evade the human immune system. Vaccines for new strains are developed each season, and an identification test confirming the specific strain is essential for vaccine quality control, as stated by the U.S. Food and Drug Administration. However, a shorter timeline of antibody discovery was required to adjust vaccine development schedules. Therefore, anti-SARS-CoV-2 strain-specific, single-domain antibodies (sdAbs) for SARS-CoV-2 vaccines were discovered using alpaca synthetic libraries without animal immunization. Methods: A synthetic sdAb library was developed based on conserved alpaca sdAb frameworks, with a degree of freedom in the three complementarity-determining regions. Specific and high-affinity sdAb clones were selected from the library by one ribosomal display round, followed by two phage display selections using a biotinylated strain-specific SARS-CoV-2 receptor-binding domain (RBD) of the spike protein as bait and non-biotinylated RBD variants to block. The sdAbs clones were applied to the identification test using Western blotting. The binding epitopes were determined by hydrogen-deuterium exchange mass spectrometry. Results: Five clones of XBB.1.5 and two clones of JN.1-specific sdAbs were discovered. Anti-JN.1 sdAb clone 1B9 detected JN.1 vaccine products but no other previously produced vaccine strains, Wuhan, BA.5 and XBB.1.5, by WB for vaccine identification test. Four binding epitopes for anti-JN.1 sdAb clone 1B9 were identified, including the L455S mutation, a critical amino acid to evade neutralizing antibodies for the JN.1 strain. Conclusions: Anti-XBB.1.5 and JN.1-specific sdAbs were discovered from a synthetic single-domain antibody library within 8-9 weeks, and these sdAbs were applied to vaccine identification testing.
Background/Objectives: The immunoglobulin heavy-chain variable (IGHV) gene repertoire represents a characteristic feature of chronic lymphocytic leukemia (CLL), although its configuration is not well defined at the early disease stages. The IGHV repertoire of a cohort of early CLL patients was analyzed and compared to that of a "real-world" reference cohort. Methods: Patients from the O-CLL1 observational protocol, which enrolled only Binet stage A cases within twelve months from diagnosis, were studied. IGHV/IGHJ rearrangements were sequenced and annotated following ERIC recommendations, and stereotyped subsets were assigned using ARResT/AssignSubsets. The repertoire features were compared with the dataset of a real-world cohort of patients with heterogeneous staging (CTR cohort) and with published early-diagnosis series. Results: IGHV and IGHJ gene distributions and HCDR3-length profiles in O-CLL1 closely mirrored those of CTR, indicating that the BcR IG repertoire at diagnosis is already defined rather than being selected during disease progression. Mutated IGHV (M-CLL) predominated, with a frequency of stereotyped BcR IG comparable to that of other early-diagnosis cohorts. However, within this conserved framework, subset #4 was over-represented among M-CLL from O-CLL without an increased overall IGHV4-34 gene usage, suggestive of a selective expansion rather than a recombinational bias. Subset #4 cases retained canonical HCDR3 motifs and showed time-to-first-treatment like other M-CLL, likely reflecting the younger age structure of O-CLL1. Conclusions: Early-diagnosis CLL displays a biased IGHV repertoire with stereotyped configurations characteristic of CLL, including subsets that are rare in the normal B-cell repertoire. These findings support a central role for antigen-driven selection in shaping CLL evolution.
Objectives: The epidermal growth factor receptor (EGFR) is a clinically relevant membrane receptor that is frequently overexpressed or dysregulated in multiple types of cancer, making it an important target for antibody-based strategies. Nanobodies, derived from camelid heavy-chain antibodies, possess favorable properties such as small size, high stability, and strong antigen-binding capacity. This study aimed to generate EGFR-specific nanobodies and to systematically characterize their binding properties and initial functional activity. Methodology: Bactrian camels were immunized with a whole-cell antigen prepared from 293F cells transiently transfected to express full-length human EGFR. A high-diversity phage display nanobody library was constructed from peripheral blood lymphocytes. After two rounds of biopanning against EGFR, positive clones were screened and selected. The identified nanobodies were recombinantly expressed in Escherichia coli and purified. Binding specificity, epitope relationships, and kinetic parameters were evaluated using high-performance liquid chromatography (HPLC), bio-layer interferometry (Octet), and flow cytometry. The effect of selected nanobodies on EGF-induced cell proliferation was evaluated using a CCK-8 assay. Results: Two EGFR-specific nanobodies, Nb2H4 and Nb2B6, were successfully isolated. Both nanobodies exhibited specific binding to EGFR and recognized distinct, non-competing epitopes. Kinetic analyses revealed favorable binding affinities, and flow cytometry confirmed their ability to recognize EGFR in its native cellular context. In addition, Nb2H4 significantly suppressed EGF-induced proliferation in an EGFR-overexpression cell model, indicating preliminary functional activity. Conclusions: This study reports on the successful generation and in vitro characterization of EGFR-targeting nanobodies based on the extracellular domain of EGFR. The identified nanobodies provide useful molecular tools for epitope mapping, structural studies, and the further exploration of EGFR-directed antibody engineering strategies.
BACKGROUND:Anti-double-stranded DNA (anti-dsDNA) antibodies are a key serological marker for systemic lupus erythematosus (SLE) and are commonly assessed in conjunction with anti-nuclear antibody (ANA) testing by indirect immunofluorescence (IIF) on HEp-2 cells. However, their detection is influenced both by the heterogeneity of the autoimmune response and by the characteristics of the analytical method employed, thereby complicating diagnostic interpretation. METHODS:In this retrospective single-center study, 3090 consecutive patients undergoing anti-dsDNA analysis were screened, and 138 positive individuals, with anti-dsDNA levels ≥ 15 IU/mL by fluoroenzyme immunoassay (FEIA), were included in the study. A control group of 29 anti-dsDNA-negative patients was also analyzed. Anti-dsDNA-positive patients were stratified by antibody level (low, mild, high), and the results were correlated with HEp-2 IIF titers and fluorescence patterns. Furthermore, in a subset of 30 positive patients, anti-dsDNA antibodies were evaluated using immunoblotting (IB) and the Crithidia luciliae indirect immunofluorescence test (CLIFT). Statistical analyses assessed associations and concordance among methods. RESULTS:Higher anti-dsDNA levels were generally associated with higher HEp-2 IIF titers. However, a considerable percentage (35%) of patients with positive anti-dsDNA were negative by HEp-2 IIF. Notably, high anti-dsDNA levels were detected in 19% of HEp-2 IIF-negative patients (titer < 1:80), 18% of mildly HEp-2 IIF-positive patients (titer 1:80-1:160), and 25% of HEp-2 IIF-positive patients (titer > 1:320). In the subset of 30 positive patients, FEIA analysis showed high concordance with the immunoblot in both IIF-positive (81%) and -negative (100%) patients, while CLIFT demonstrated lower agreement with both FEIA and IB independently of the IIF. CONCLUSIONS:Our findings indicate that anti-dsDNA antibody detection may occur independently of HEp-2 IIF positivity and that FEIA, especially when confirmed by immunoblot, represents a reliable approach for anti-dsDNA assessment. The observed results in this study likely reflect differences in epitope recognition and assay sensitivity among methods, suggesting the use of a multi-step diagnostic strategy in the serological evaluation of SLE.
Background/Objectives: Viral hepatitis A-E represents a significant public health problem. Data on the prevalence of viral hepatitis markers among alcoholics are inconsistent. Methods: The study included 151 patients treated for alcohol abuse in one Croatian center. The control group consisted of 110 individuals from the general population tested for a routine check-up. The prevalence of viral hepatitis markers was assessed using serology and molecular methods. Results: The prevalence rates of hepatitis markers among patients were as follows: anti-HAV, 15.2%; anti-HBs, 11.9%; anti-HBc/anti-HBs, 2.6%; anti-HCV, 4.0%; and anti-HEV, 14.6%. HCV RNA was detected in one patient (0.6%). Compared with the control group, patients showed significantly higher HCV seroprevalence (4.0 vs. 0%), while the prevalence of other hepatitis markers did not differ significantly between the groups. The anti-HAV prevalence was associated with age (from 0% in patients aged <40 years to 42.9% in patients aged 60+ years), employment status (highest among retired individuals at 46.2%), and age of occasional alcohol consumption (highest seroprevalence of 26.3% in those who reported consumption between 22 and 25 years). The association between anti-HEV and educational level was of borderline significance. Logistic regression showed that older and retired patients and those who consumed alcohol occasionally between 22 and 25 years showed higher odds for HAV seropositivity (OR = 11.454-49.400, OR = 6.857, and OR = 4.464, respectively). Patients with university degrees were at lower risk for HEV seroprevalence (OR = 0.083). Conclusions: Alcoholic patients showed a higher HCV seroprevalence than the general population, while the prevalence of other viral hepatitis markers did not differ between the groups. Further studies on a larger cohort of patients are needed to confirm these findings.
Background: Collagen XIα1, encoded by the COL11A1 gene, is a minor fibrillar collagen that is overexpressed in various human cancers, in which its presence correlates with tumor aggressiveness and progression. Methods: In this study, we developed two novel mouse monoclonal antibodies (mAbs)—anti-colXIα1 clone 3 and anti-colXIα1 clone 9—that target the putative C-telopeptide of human collagen XIα1. These antibodies target the RRHTEGMQA sequence, a unique nine-amino-acid stretch within the putative C-telopeptide of human collagen XIα1. Results: Corresponding to nearly identical V(D)J gene segments and complementarity-determining regions (CDRs), the antibodies specifically bound the RRHTEGMQA epitope in ELISAs but did not react with the C-propeptide. This specificity was further confirmed with the purified anti-colXIα1 clone 9 mAb, which demonstrated strong reactivity against recombinant proteins containing the RRHTEGMQA sequence in both ELISAs and Western blot assays. This sequence seems to behave as a linear B-cell neoepitope, in which the RRHT motif is crucial for epitope recognition. Otherwise, no immunodetections were observed, either in cultures and lysates from the COL11A1-highly expressing A204 human cell line or on tissue sections from specimens of human pancreatic ductal adenocarcinoma (PDAC), with strong desmoplastic reactions. Conclusions: Given the lack of precise knowledge of the characteristics of the putative C-telopeptide of human collagen XIα1, the presented antibodies could enhance our understanding of the processing of human procollagen XIα1 and contribute to better characterization of the tumor microenvironment of COL11A1-expressing cancers.
Background/Objectives: Developability assessment is a critical step in advancing antibody-based molecules toward clinical application. This evaluation typically begins during clinical candidate selection and continues throughout all modifications of the molecule during development. It is guided by the target product profile, which includes the intended administration route and regimen, formulation parameters, and process conditions encountered during manufacturing, storage, and delivery. While developability testing is well established for conventional therapeutic antibodies, strategies for assessing single-domain antibodies (sdAbs) and their conjugates remain underexplored. Here, we present a strategy to test the developability of sdAbs as a case study for two clinical candidates intended as precursors for the production of diagnostic tracers for clinical imaging. Methods: Assays were developed to evaluate chemical and thermodynamic stability, target binding affinity and capacity, and chelation efficiency ("chelatability"). Accelerated stability studies were conducted for both unconjugated sdAbs and their chelator conjugated forms following incubation at two pH conditions, at multiple time points, and after twelve freeze-thaw cycles to simulate process conditions and long-term storage. Analytical assays were applied stepwise in a hierarchical approach to minimize experimental effort and material consumption. Candidates exhibiting critical developability features were selectively addressed by assays with increasing precision. Results: A tailored panel of analytical assays optimized for low molecular weight proteins was established and applied to the two clinical candidates, identifying instability hotspots as well as potential mitigation strategies. Successful engineering of a candidate with an initially critical developability profile was achieved. Conclusions: This study demonstrates the implementation of a structured developability assessment strategy for sdAb conjugates. The approach integrates physicochemical and functional stability evaluations, supporting robust candidate selection, formulation development, and method optimization for this class of molecules.
Background/Objectives: Schlafen (SLFN) 8 and SLFN9 are mouse members of the Schlafen protein family, believed to have arisen through a gene duplication event. The physiological roles of these proteins remain poorly defined, in part due to the absence of reliable, commercially available antibodies for their detection. Methods: To develop specific antibodies, we performed an amino acid sequence alignment of these proteins and identified a thirteen amino acids long peptide predicted by AlphaFold modeling and hydropathicity analysis to be surface-exposed in both SLFN proteins. The SLFN8 peptide was conjugated to KLH and used to immunize mice, employing Poly(I:C) as an adjuvant. Results: We verified the anti-SLFN8 antibody specificity in mouse tissues, engineered human cells, and recombinant proteins by different immunodetection techniques, including Western blotting, immunoprecipitation, immunohistochemistry, and ELISA. Furthermore, splenocytes from immunized mice were used to generate hybridomas that secreted IgG antibodies with SLFN8-peptide specificity, as assumed by ELISA. Conclusions: Our results demonstrate that the identified peptide is highly immunogenic and capable of eliciting antibodies that distinguish between these two exceedingly similar proteins in a broad group of immunodetection techniques.
