Total Antibody Research Articles

Serologic Testing of US Blood Donations to Identify Severe Acute Respiratory Syndrome Coronavirus 2 and Other Coronaviruses, December 2019 to July 2020.

The first coronavirus disease 2019 (COVID-19) case in the United States was recognized on 19 January 2020, but the time of introduction of the virus into the United States is unknown. An existing sample cohort was examined for serologic evidence of early severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. A repository of 46 120 samples from healthy routine blood donors, representing 46 states and the District of Columbia, was tested for total antibodies to SARS-CoV-2 nucleocapsid (anti-N) using a commercial test. All reactive samples were further tested using an experimental receptor-binding domain (RBD)-specific immunoglobulin G (IgG) enzyme-linked immunosorbent assay. Further testing was also conducted for anti-spike (anti-S) antibodies by commercial tests, experimental anti-S immunologic blocking, and for antibodies to the 4 human cold coronaviruses. Anti-N reactivity was observed in 92 tested samples (0.2%), 91 of which had adequate volume for further testing; of these, 55 were confirmed positive by anti-RBD. None of these reactive findings were attributable to the other human coronaviruses tested. The confirmed-positive frequency increased over time paralleling patterns observed for COVID-19 cases reported in the United States (in contrast to stable patterns over time for the cold coronaviruses). Nine confirmed positive samples (0.07%) were identified among the 13 364 donations collected between 13 December 2019 and 22 January 2020. None of these early confirmed-positive samples were reactive by commercial anti-S tests suggesting very recent infection. The samples tested in this study were broadly representative of the United States, and all were from individuals who had successfully donated blood. The antibody-reactive results of this study suggest that SARS-CoV-2 was likely present in the United States before 19 January 2020.

Development and validation of bioanalytical assays for the quantification of 9MW2821, a nectin-4-targeting antibody–drug conjugate

We designed and developed 9MW2821, an anti-Nectin-4 antibody–drug conjugate (ADC) with an enzymatically cleavable valine–citrulline linker and monomethyl auristatin E (MMAE) as the payload. Four bioanalytical assays for total antibodies, conjugated antibodies, conjugated payload, and free payload were then developed and validated for the comprehensive evaluation of the multiple drug forms of 9MW2821. Specific sandwich enzyme-linked immunosorbent assays were used to quantify total antibodies and conjugated antibody, showing good drug-to-antibody ratio (DAR) tolerance. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to determine free MMAE, and conjugated MMAE was quantified using a combination of ligand-binding assay (LBA) and LC-MS/MS. Based on these four assays, we studied the serum stability and monkey pharmacokinetic profiles of 9MW2821, and the in vivo DAR of 9MW2821 was calculated and dynamically monitored. In conclusion, we developed and validated series of bioanalytical assays to quantify multiple forms of 9MW2821, a new ADC, and used the assays to evaluate the serum stability and monkey pharmacokinetic characteristics. The results indicate good linker stability and suggest that the developed assays can be further used in clinical settings.

Exploring the effects of varying levels of selenium-chitosan on production performance, egg quality, and immune health in laying japanese quail

The purpose of this research was to see how different levels of Se-chitosan, a novel organic source of Se, affected the production performance, egg quality, egg Se concentration, microbial population, immunological response, antioxidant status, and yolk fatty acid profile of laying Japanese quail. This experiment used a totally randomized design, with 5 treatments, 6 repeats, and 10 birds in each repetition. The dietary treatment groups were as follows: no Se supplementation (control group), 0.2 mg/kg Na-selenite supplementation, and 0.2, 0.4, and 0.6 mg/kg Se-chitosan supplementation. The feed conversion ratio (FCR) improved linearly in quails fed different levels of Se-chitosan compared to the control group (P < 0.05). Furthermore, Se-chitosan at concentrations of 0.2 and 0.4 mg/kg demonstrated both linear and quadratic increases in albumen height, Haugh unit, and yolk color in fresh eggs compared to the control group. Additionally, Se-chitosan contributed to enhanced shell thickness and strength, along with an increased Se concentration in the yolk. Se-chitosan supplementation at different levels linearly and quadratically reduced coliforms (COL) while increasing lactic acid bacteria (LAB)/coliform ratios (P < 0.05). Se-chitosan supplementation linearly and quadratically increased the total antibody response to sheep red blood cells (SRBC) and IgG titers (P < 0.05). It also linearly decreased the level of malondialdehyde in fresh and stored egg yolks and increased the activity of antioxidant enzymes catalase and glutathione peroxidase linearly, and superoxide dismutase (SOD) both linearly and quadratically in quail blood serum (P < 0.05). Additionally, supplementation of Se-chitosan at levels of 0.2 and 0.6 mg/kg linearly decreased the ∑ n-6 PUFA/∑ n-3 PUFA ratio in the yolk compared to the control group (P < 0.05). It can be concluded that incorporating Se-chitosan as a novel organic source of Se in the diet of laying quails can enhance production performance, egg quality, egg Se concentration, yolk lipid oxidation, microbial population, immune response, antioxidant enzyme activity, and yolk fatty acid profile.

Review of the U.S. Air Force Academy Hepatitis C Virus Screening Program to Ensure High-Value Care.

Hepatitis C virus (HCV) is primarily transmitted through blood-to-blood contact. Leading health agencies have called for the elimination of HCV as a public health threat, with universal screening considered a part of the strategy. Hepatitis C virus screening among incoming cadets and cadet candidates at the United States Air Force Academy (USAFA) was implemented in 2023. The purpose of this quality improvement project was to determine the results of this screening and the associated fiscal costs, benefits, and harms to make a recommendation for future incoming classes. The prevalence of HCV antibody positivity and confirmed HCV infections were calculated among the incoming cadets and cadet candidates at USAFA in summer 2023. Screening was conducted with a highly sensitive HCV total antibody test, and those who screened positive were further tested with a quantitative HCV polymerase chain reaction. The screening and follow-up care costs were calculated, and the potential harm of receiving a false positive notification was considered. Of the 1,360 persons screened at USAFA in 2023, no confirmed HCV infections were identified. There was one false positive on screening in the cadet population (n = 1,131) and one false positive in the cadet candidate population (n = 229). The fiscal cost of universal HCV screening upon accession of cadets and cadet candidates, including medical follow-up, was at least $5,279. The opportunity cost was minimal because blood was drawn for other mandatory programs, although screening may have caused social and psychological harm to those receiving a false positive notification. The prevalence of chronic HCV infection among incoming USAFA cadets and cadet candidates was 0%, below the population screening threshold that warrants screening, according to the Centers for Disease Control and Prevention. The harms of screening, including fiscal costs and potential psychological harm to individuals with a false positive screen, likely outweigh the benefits. We recommend against universal HCV screening in 2024 upon accession of USAFA cadets and cadet candidates.

Immune responses and reinfection of SARS-CoV-2 Omicron variant in patients with lung cancer.

A significant Omicron wave emerged in China in December 2022. To explore the duration of humoral and cellular response postinfection and the efficacy of hybrid immunity in preventing Omicron reinfection in patients with lung cancer, a total of 447 patients were included in the longitudinal study after the Omicron wave from March 2023 to August 2023. Humoral responses were measured at pre-Omicron wave, 3 months and 7 months postinfection. The detected severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) specific antibodies including total antibodies, anti-receptor binding domain (RBD) specific IgG, and neutralizing antibodies against SARS-CoV-2 wild type (WT) and BA.4/5 variant. T cell responses against SARS-CoV-2 WT and Omicron variant were evaluated in 101 patients by ELISpot at 3 months postinfection. The results showed that Omicron-infected symptoms were mild, while fatigue (30.2%), shortness of breath (34.0%) and persistent cough (23.6%) were long-lasting, and vaccines showed efficacy against fever in lung cancer patients. Humoral responses were higher in full or booster vaccinated patients than those unvaccinated (p < .05 for all four antibodies), and the enhanced response persisted for at least 7 months. T cell response to Omicron was higher than WT peptides (21.3 vs. 16.0 SFUs/106 PBMCs, p = .0093). Moreover, 38 (9.74%) patients were reinfected, which had lower antibody responses than non-reinfected patients (all p < .05), and those patients of unvaccinated at late stage receiving anti-cancer immunotherapy alone were at high risk of reinfection. Collectively, these data demonstrate the Omicron infection induces a high and durable immune response in vaccinated patients with lung cancer, which protects vaccinated patients from reinfection.

BC3195, a novel ADC targeting CDH3: Preliminary results of a first-in-human phase I study in patients with advanced solid malignancies.

e15008 Background: Cadherin-3 (CDH3), a calcium-dependent cell-cell adhesion glycoprotein, is overexpressed on lung, breast, ovarian, colorectal, pancreatic, head and neck and other malignancies, but with negligible expression on nonmalignant tissues, and associated with cancer aggressiveness, invasiveness, and poor prognosis. BC3195 is known as the only antibody drug conjugate (ADC) in clinical stage, targeting CDH3 with payload of monomethyl auristatin E (MMAE). Methods: A phase I, open-label, first in human study to evaluate the safety, tolerability, PK, and preliminary antitumor activity of BC3195 is being performed in subjects with advanced solid malignancies. Disease assessments are performed every 6 weeks using RECIST v1.1. BC3195 is administered as 1 hour (h) IV infusion every 3 weeks. An evaluation of seven dose levels is planned: 0.3, 0.6, 1.2, 2.4, 3.0 and 3.6 mg/kg with a BOIN design guiding dose escalation. Results: Up to January 1st, 2024, nine patients (median age, 59; male, 56%) have been enrolled and treated with BC3195, with 3 patients each in the 0.3, 0.6 and 1.2 mg/kg dose cohorts. No DLT was observed across all the 3 dose cohorts. Treatment emergent adverse events (TEAEs) occurring in ≥3 patients included: aspartate aminotransferase increased (5/9, 55.6%), conjugated bilirubin increased (5/9, 55.6%), triglycerides increased (4/9, 44%), uric acid increased (3/9, 33.3%), heart rate increased (3/9, 33%), and hypoalbuminemia (5/9, 55.6%), cough (4/9, 44.4%), hyponatraemia (4/9, 44.4%), anemia (4/9, 44.4%), asthenia (3/9, 33.3%), rash (3/9, 33.3%), vomiting (3/9, 33.3%) and back pain (3/9, 33.3%). Two subjects experienced ≥ Grade 3 TEAEs unrelated to study drug. Six subjects were evaluable for tumor assessment, and 3 subjects (3/6, 50%) show stable disease (SD) as the best response (2 subjects with target lesion reduction). PK results demonstrated that exposure for the ADC and total antibody (TA) increased with dose, the relationship between AUC0-last and dose was greater than dose-proportional, while Cmax was linear. Free MMAE was highest at the 1.2 mg/kg dose level. Median Tmax values for ADC and TA were 1 h (end of infusion), and median Tmax for free MMAE was 25-169 h. In addition, elimination t1/2 values averaged 27-48 h, 31-68 h and 63-76 h for the ADC, TA, and MMAE, respectively. Conclusions: BC3195 exhibited favorable safety profile and PK characteristics up to 1.2mg/kg. Given BC31095’s safety and PK behavior, as well as preliminary activity at the 0.6 mg/kg dose level, patient enrollment at higher dose levels is ongoing. Clinical trial information: NCT05957471 .

ARTEMIS-001: Data from a phase 1a/b study of HS-20093 in patients with relapsed small cell lung cancer (SCLC).

8093 Background: SCLC is characterized by a high rate of proliferation and poor prognosis, and new therapies are urgently needed. B7-H3 is highly expressed in SCLC. HS-20093, a B7-H3-targeted antibody-drug conjugate (ADC), demonstrated antitumor activity in advanced solid tumors in the dose escalation part of ARTEMIS-001 study (Jie Wang et al., JCO, 2023) (NCT05276609). Here, we present results on the efficacy and safety of the expansion doses in patients (pts) with SCLC from phase 1a/b. Methods: ARTEMIS-001 study consisted of dose escalation (1a) and expansion (1b) part. Pts were treated with doses of 1.0 to 16.0 mg/kg HS-20093 every 3 weeks in dose escalation, and were treated with doses at 8.0 mg/kg and 10.0 mg/kg randomly in dose expansion. Pts with SCLC were required to have received prior platinum-based standard therapy. B7-H3 expression was retrospectively evaluated by IHC. Results: As of data cutoff November 30th 2023, a total of 56 pts with extensive stage SCLC (ES-SCLC) were enrolled and received ≥1 dose of HS-20093 with doses at 8.0 mg/kg (n=31) or 10.0 mg/kg (n=25). Median prior lines of therapy was 2.0 (range: 1-6). All pts received platinum plus etoposide and 73.2% (41/56) received immunotherapy. Safety profile was consistent with previous reports. The most common grade≥3 treatment-related adverse events (≧10%) were neutropenia, leukopenia, lymphopenia, thrombocytopenia and anemia. Out of 56 pts, 52 pts were efficacy evaluable (8.0 mg/kg: 31 pts; 10.0 mg/kg: 21 pts). HS-20093 showed encouraging efficacy in relapsed ES-SCLC (Table). Tumor shrinkage in target lesions occurred in 96.2% (50/52) pts with a post-baseline scan. Deep response defined as tumor shrinkage ≥50% was obtained in 44.2% (23/52) pts. Median overall survival has not yet reached. Responses were observed regardless of B7-H3 expression. Pharmacokinetic (PK) showed approximately dose-proportional increase in exposure with a half-life of 3-7 days. PK profiles of total antibody and ADC were similar and exposure to payload was considerably low. Conclusions: HS-20093 demonstrated promising antitumor activity and manageable safety in pts with previously-treated SCLC. Phase 3 study is planned to compare the efficacy and safety of HS-20093 with standard-of-care chemotherapy in relapsed SCLC. Clinical trial information: NCT05276609 . [Table: see text]

A phase 1a/b, multi-regional, first-in-human study of CS5001, a novel anti-ROR1 ADC, in patients with advanced solid tumors and lymphomas.

3023 Background: Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an embryonic tyrosine kinase-like molecule implicated in multiple pathways promoting oncogenic signaling. ROR1 is overexpressed in a broad spectrum of solid tumors and hematological malignancies while notably absent in normal tissues. CS5001 is an antibody drug conjugate (ADC) composed of a human anti–ROR1 IgG1 monoclonal antibody which is site-specifically conjugated to a pyrrolobenzodiazepine dimer prodrug through a proprietary lysosomal cleavable β-glucuronide linker. Here, we report preliminary phase 1a results of CS5001 in patients (pts) with advanced solid tumors and lymphomas. Methods: This is a global, first-in-human, phase 1a/b study evaluating the safety, pharmacokinetics (PK), and anti-tumor activity of CS5001 in pts with advanced solid tumors and lymphomas. CS5001 was administered intravenously Q3W with a 42-day-DLT period. In phase 1a (dose escalation), pts who had progressed on or been intolerant to standard therapies were enrolled without baseline ROR1 expression testing; accelerated titration followed by Bayesian Optimal Interval design was employed; in parallel with dose escalation, additional pts were enrolled to selected dose levels deemed safe to further evaluate safety and efficacy. Results: As of 15 Jan 2024, 49 pts with lymphomas (n=17) and solid tumors (n=32) were treated across 8 dose levels (7 to 125 μg/kg). Median age was 57 years. Most (n=40, 81.6%) pts had received ≥3 lines of prior anti-tumor treatment. No DLT was observed and MTD was not reached. Treatment-related adverse events (TRAEs) occurred in 29 pts (59.2%); the most common TRAE was fatigue (n=8, 16.3%). Grade 3 TRAEs occurred in 7 pts (14.3%), with fatigue, gamma-glutamyltransferase increased and pneumonia being the most common (occurring in 2 pts [4.1%] each). No grade 4-5 TRAEs were reported. Drug exposure of CS5001 was proportional to dose in general, with an apparent half-life of about 5 days. The PK profile of CS5001 was similar to that of total antibody, indicating good stability of the ADC in the circulation. Among the 34 pts with post baseline tumor assessment (13 lymphomas and 21 solid tumors), objective responses were observed in pts at dose level 5 or above (n=23), including 2 complete responses (1 Hodgkin lymphoma [HL] and 1 diffuse large B-cell lymphoma) and 3 partial responses (2 HL and 1 pancreatic cancer). Stable diseases were observed in 3 pts (2 colorectal cancer and 1 renal cancer). Dose escalation is still ongoing, and more data will be available at the conference presentation. Conclusions: CS5001 was well tolerated with no DLT identified, PK characteristics were as expected, and encouraging antitumor activities were observed in various advanced solid tumors and lymphomas. Current data support continued evaluations for the recommended phase 2 dose and subsequent phase 1b dose expansion. Clinical trial information: NCT05279300 .

Phase 1 study of ZV0203, a first in class pertuzumab ADC, in patients with HER2 positive advanced solid tumors.

e15004 Background: ZV0203, a first in class (FIC) pertuzumab antibody-drug conjugate (ADC), targets HER2 positive tumor cells with tubulin inhibitor DUO5 as its payload via a stable and protease-cleavable valine-citrulline linker. In preclinical studies, ZV0203 demonstrated superior antitumor activity compared to Kadcyla in multiple tumor cell line xenograft models with no noticeable toxicity. GLP toxicity studies indicated that ZV0203 was well tolerated with an estimated therapeutic index of 35. Methods: This was an open-label, multicenter, phase 1, dose-escalation study in patients (pts) with HER2+ advanced solid tumors. Primary objectives were safety, tolerability and RP2D. Secondary objectives included PK, immunogenicity and preliminary clinical efficacy. ZV0203 was administered intravenously Q3W on a 21-day cycle. An accelerated titration design was used for the 0.3 and 0.6 mg/kg doses, followed by a 3+3 design for 1.2, 1.8, 2.7 and 3.6 mg/kg dose levels. Results: As of January 18, 2024, 15 pts with solid tumors (breast [11], colorectal [2], gastric [1], lung [1]) were enrolled across doses of 0.3-3.6 mg/kg with a median age of 52 years old (range 35-65), of which 9 pts received prior HER2-targeted therapy (trastuzumab ± pertuzumab) and 14 pts completed 21-day DLT assessment (0.3 mg/kg and 0.6 mg/kg [1 each], 1.2 mg/kg, 1.8 mg/kg, 2.7 mg/kg and 3.6mg/kg [3 each]) with no DLT incidence. Treatment-related adverse events (TRAE) occurred in 14 (93.3%) pts. The most frequent TRAEs were corneal epitheliopathy [9], elevated liver enzymes [6], dry eyes [6], neutropenia [4], anemia [4], leukopenia [3], and proteinuria [3], and most were grade 1-2 in severity. 5 pts experienced grade 3 TRAEs: lymphocytopenia (1.8mg/kg [1]) , corneal epitheliopathy (3.6 mg/kg [1]) and blurred vision (2.7 mg/kg [2], 3.6 mg/kg [1]), which were manageable during treatment. No unexpected safety signals were reported. TRAEs led to 13.3% (2/15) treatment discontinuation. Among 14 pts evaluated, 5 pts achieved a best tumor response of PR; 4 pts had SD; 1 pt had Non-CR/Non-PD per RECIST v1.1. Thus, disease control rate was 71.4% (10/14). PK results demonstrated that the PK profile of total antibody was similar to that of ZV0203 ADC, whose systematic exposure increased in a dose-dependent manner and remained stable after repeated administration. Concentration of DUO5 remained scarce, suggesting good stability of ZV0203. Conclusions: ZV0203 was well tolerated and showed clinically encouraging anti-tumor activity in heavily pretreated pts with HER2 positive cancer. Clinical trial information: NCT05423977 .

An open-label, multicenter, phase I study of ATG-022 in patients with advanced/metastatic solid tumors (CLINCH).

3032 Background: Claudin 18.2 (CLDN 18.2) is a tumor associated antigen broadly expressed in gastric, pancreatic, and other solid tumors. ATG-022 is an antibody drug conjugate (ADC), consisting of a humanized monoclonal antibody that binds to CLDN 18.2 with high affinity of sub-nM grade and a conjugated linker-payload vc-MMAE. ATG-022 has displayed promising tumor growth inhibition activity both in vitro and in vivo. Methods: CLINCH is a phase I, multi-center, open-label, dose-finding study (NCT05718895) of ATG-022 in patients with advanced solid tumours. The study design includes a dose escalation phase, enrolling subjects with advanced/metastatic solid tumors, regardless of CLDN 18.2 expression, and a dose expansion phase which will enroll select advanced/metastatic solid tumors with CLDN 18.2-positive expression at the defined maximum tolerated dose and/or recommended Phase 2 dose to further evaluate the safety, tolerability, and efficacy of ATG-022. Other endpoints include pharmacokinetics (PK) and exploratory biomarkers of drug activity. In the dose escalation phase, ATG-022 is administered intravenously every 3 weeks (Q3W) at the starting dose of 0.3 mg/kg, followed by 0.9, 1.8, 2.4, 3.0, and 3.6 mg/kg Q3W using a modified 3+3 dose-escalation design. Efficacy assessments are evaluated per RECIST1.1 criteria. Results: As of 9 Oct 2023, 10 patients (pts) with advanced solid tumors have been enrolled to receive ATG-022 at a dose from 0.3 to 2.4 mg/kg. Median age was 59 years. Baseline ECOG scores were 0 (0 pts) and 1 (10 pts); 8 pts had stage IV disease. Three pts had received more than 3 prior lines of systemic therapy. Eight pts (80%) had ≥ 1 TRAEs; 1 pt (10%) had ≥ 1 Serious TRAEs; 3 (30%) pts had grade ≥ 3 TRAEs. The most common grade ≥ 3 TRAEs included nausea (30%), vomiting (30%) and decreased appetite (30%). No DLT was reported among the current dose levels. Among 7 pts with gastric cancer, 3 pts are confirmed to be CLDN 18.2 positive. One of these pts has maintained stable disease with tumor shrinkage for more than 6 months (treatment ongoing) at a dose of 0.9 mg/kg, demonstrating tolerability of ATG-022. One PR was observed in a gastric cancer pt (CLDN 18.2 expression to be determined) at the dosage of 1.8 mg/kg. It was noteworthy that a CR was seen in a gastric cancer pt dosed at 2.4 mg/kg, with negative CLDN 18.2 expression. PK analysis of ATG-022 from 0.3 to 2.4 mg/kg revealed that the exposure of total antibody, MMAE and ADC drug is increased as dose increased. No accumulation of ATG-022 was observed. Conclusions: ATG-022 demonstrated preliminary anti-tumor activity, tolerability, safety, as well as comparable PK properties at current dose levels. The high affinity of sub-nM grade of ATG-022 in pts with low CLDN 18.2 expression needs further investigation. The dose escalation is ongoing and updated data will be presented. Clinical trial information: NCT05718895 .

RBD mutations at the residues K417, E484, N501 reduced immunoreactivity with antisera from vaccinated and COVID-19 recovered patients.

It is unclear whether induced spike protein-specific antibodies due to infections with SARS-CoV-2 or to the prototypic Wuhan isolate-based vaccination can immune-react with the emerging variants of SARS-CoV-2. The main objective of the study was to measure the immunoreactivity of induced antibodies postvaccination with Covishield™ (ChAdOx1 nCoV-19 coronavirus vaccines) or infections with SARS-CoV-2 by using selected peptides of the spike protein of wild type and variants of SARS-CoV-2. Thirty patients who had recovered from SARS-CoV-2 infections and 30 individuals vaccinated with both doses of Covishield™ were recruited for the study. Venous blood samples (5 mL) were collected at a single time point from patients within 3-4 weeks of recovery from SARS-CoV-2 infections or receiving both doses of Covishield™ vaccines. The serum levels of total immunoglobulin were measured in both study groups. A total of 12 peptides of 10 to 24 amino acids length spanning to the receptor-binding domain (RBD) of wild type of SARS-CoV-2 and their variants were synthesized. The serum levels of immune-reactive antibodies were measured using these peptides. The serum levels of total antibodies were found to be significantly (p<0.001) higher in the vaccinated individuals as compared to COVID-19 recovered patients. Our study reported that the mutations in the RBD at the residues K417, E484, and N501 have been associated with reduced immunoreactivity with anti-sera of vaccinated people and COVID-19 recovered patients. The amino acid substitutions at the RBD of SARS-CoV-2 have been associated with a higher potential to escape the humoral immune response.

The seroprevalence of antibodies to Japanese encephalitis virus in five New South Wales towns at high risk of infection, 2022: a cross-sectional serosurvey.

To determine the proportion of people in New South Wales towns at high risk of Japanese encephalitis virus (JEV) infections during the 2022 outbreak; to identify risk factors for JEV infection. Cross-sectional serosurvey study of the seroprevalence of JEV-specific antibodies in NSW. Convenience sample of people (all ages) from five regional NSW towns deemed to be at high risk of JEV infections after first outbreak of Japanese encephalitis in southeastern Australia in early 2022 (Balranald, Corowa, Dubbo, Griffith, Temora), 21 June - 22 July 2022. Proportion of people seropositive for JEV total antibody, assayed by defined epitope-blocking enzyme-linked immunosorbent assay; prevalence odds ratios for exposure risk factors and protective behaviours. Eighty of 917 eligible participants (559 girls or women, 61%; 42 Aboriginal and Torres Strait Islander people, 4.6%; median age, 52 years [IQR, 37-62 years]) were seropositive for JEV-specific total antibody (8.7%); the median age of seropositive people was 61 years (IQR, 48-70 years). The seropositivity proportion was largest for people aged 65 years or more (30 of 192; weighted proportion, 13.7%) and larger for male than female participants (30 of 358, 10.6% v 50 of 559, 7.5%). Five of 42 samples from Aboriginal and Torres Strait Islander participants were seropositive (12%). We found mixed associations with a range of potential risk factors. We found evidence for a substantial number of JEV infections in five regional NSW towns during a single arbovirus season in 2022. Public health responses, including effective surveillance, vaccination against JEV, and mosquito management, are critical for controlling outbreaks. Promoting behaviours that reduce exposure to mosquitoes is a core component of prevention, particularly when the vaccine supply is limited.

Nano-Assembled Polyphosphazene Delivery System Enables Effective Intranasal Immunization with Nipah Virus Subunit Vaccine.

The ultimate vaccine against infections caused by Nipah virus should be capable of providing protection at the respiratory tract─the most probable port of entry for this pathogen. Intranasally delivered vaccines, which target nasal-associated lymphoid tissue and induce both systemic and mucosal immunity, are attractive candidates for enabling effective vaccination against this lethal disease. Herein, the water-soluble polyphosphazene delivery vehicle assembles into nanoscale supramolecular constructs with the soluble extracellular portion of the Hendra virus attachment glycoprotein─a promising subunit vaccine antigen against both Nipah and Hendra viruses. These supramolecular constructs signal through Toll-like receptor 7/8 and promote binding interactions with mucin─an important feature of effective mucosal adjuvants. High mass contrast of phosphorus-nitrogen backbone of the polymer enables a successful visualization of nanoconstructs in their vitrified state by cryogenic electron microscopy. Here, we characterize the self-assembly of polyphosphazene macromolecule with biologically relevant ligands by asymmetric flow field flow fractionation, dynamic light scattering, fluorescence spectrophotometry, and turbidimetric titration methods. Furthermore, a polyphosphazene-enabled intranasal Nipah vaccine candidate demonstrates the ability to induce immune responses in hamsters and shows superiority in inducing total IgG and neutralizing antibodies when benchmarked against the respective clinical stage alum adjuvanted vaccine. The results highlight the potential of polyphosphazene-enabled nanoassemblies in the development of intranasal vaccines.

Intact quantitation of cysteine-conjugated antibody-drug conjugates using native mass spectrometry.

A common strategy for antibody-drug conjugate (ADC) quantitation from in vivo study samples involves measurement of total antibody, conjugated ADC, and free payload concentrations using multiple reaction monitoring (MRM) mass spectrometry. This not only provides a limited picture of biotransformation but can also involve lengthy method development. Quantitation of ADCs directly at the intact protein level in native conditions using high-resolution mass spectrometers presents the advantage of measuring exposure readout as well as monitoring the change in average drug-to-antibody ratio (DAR) and in vivo stability of new linker payloads with minimal method development. Furthermore, site-specific cysteine-conjugated ADCs often rely on non-covalent association to retain their quaternary structure, which highlights the unique capabilities of native mass spectrometry (nMS) for intact ADC quantitation. We developed an intact quantitation workflow involving three stages: automated affinity purification, nMS analysis, and data processing in batch fashion. The sample preparation method was modified to include only volatile ion-pairing reagents in the buffer systems. A capillary size-exclusion chromatography (SEC) column was coupled to a quadrupole time-of-flight high-resolution mass spectrometer for high-throughput nMS analysis. Samples from two mouse pharmacokinetic (PK) studies were analyzed using both intact quantitation workflow and the conventional MRM-based approach. A linear dynamic range of 5-100 μg/mL was achieved using 20 μL of serum sample volume. The results of mouse in vivo PK measurement using the intact quantitation workflow and the MRM-based approach were compared, revealing excellent method agreement. We demonstrated the feasibility of utilizing nMS for the quantitation of ADCs at the intact protein level in preclinical PK studies. Our results indicate that this intact quantitation workflow can serve as an alternative generic method for high-throughput analysis, enabling an in-depth understanding of ADC stability and safety in vivo.

Immunogenicity of mRNA-1273 and BNT162b2 in Immunocompromised Patients: Systematic Review and Meta-analysis Using GRADE.

Immunocompromised (IC) patients mount poor immune responses to vaccination. Higher-dose coronavirus disease 2019 (COVID-19) vaccines may offer increased immunogenicity. A pairwise meta-analysis of 98 studies reporting comparisons of mRNA-1273 (50 or 100 mcg/dose) and BNT162b2 (30 mcg/dose) in IC adults was performed. Outcomes were seroconversion, total and neutralizing antibody titers, and cellular immune responses. mRNA-1273 was associated with a significantly higher seroconversion likelihood [relative risk, 1.11 (95% CI, 1.08, 1.14); P<0.0001; I2=66.8%] and higher total antibody titers [relative increase, 50.45% (95% CI, 34.63%, 66.28%); P<0.0001; I2=89.5%] versus BNT162b2. mRNA-1273 elicited higher but statistically nonsignificant relative increases in neutralizing antibody titers and cellular immune responses versus BNT162b2. Higher-dose mRNA-1273 had increased immunogenicity versus BNT162b2 in IC patients.

Plasmonic Nanograin Metasurface with Disorder‐Enhanced Biosensing for SARS‐CoV‐2 Variant and Antibodies

AbstractRecently, the concept of introducing disorder into ordered metasurfaces or periodic metastructures has shown great potential in improving their performance for light extraction, scattering, reflection, and radiation. However, its use in optical biosensing enhancement is still barely reported. Here, a kind of plasmonic biosensors based on disorder‐enhanced nanograin metasurfaces (DENMs) are proposed, and utilized for high‐sensitivity detection of SARS‐CoV‐2 Omicron variant and vaccine‐induced total antibodies. With the aim to elucidate the physics of short‐range‐disordered meta‐elements in long‐range‐ordered metastructures, the meta‐atom evolution is deduced from periodic nanohole metasurfaces to DENMs and totally disordered nanograin metasurfaces. It is found that the disorder of nanograin plays a critical role in elevating the DENM surface sensitivity of biomolecules. The DENM‐based biosensing demonstrates an extremely high diagnostic specificity with the probability P &lt; 0.0001 on distinguishing the Omicron variant from other respiratory viruses. Moreover, these biosensors are used as a convenient tool to monitor vaccine efficacy for inoculators with the third booster injections. This study implies the promise of disorder‐enhanced metasurfaces on biomedical detection and will guide their applications on virus early discovery and prevention for future mobile healthcare.

Immune response and laboratory markers in the spectrum of severity of COVID-19

BACKGROUND: Serum antibodies to SARS-CoV-2, when measured early after disease onset, may add value to the diagnosis of COVID-19. AIM: To examine the levels of serum antibodies to SARS-CoV-2 and laboratory blood parameters in hospitalized patients with COVID-19 of varying severity. MATERIALS AND METHODS: In this retrospective cohort study, we examined laboratory markers of inflammation in patients with acute COVID-19 during the 1st week of hospitalization. The levels of serum antibodies to SARS-CoV-2 were studied using commercial test systems. RESULTS: In 47% of hospitalized patients with COVID-19, during the first week of hospital stay, IgM and IgG antibodies to SARS-CoV-2 were detected, both in the case of a positive and negative PCR test. An average positive cor- relation of detected IgM and IgG with antibodies to the receptor-binding site of the S-protein of the SARS-CoV-2 virus is shown. In total, IgM and IgG antibodies to SARS-CoV-2 were most often detected in patients with a favorable course of the disease. Laboratory parameters in patients with moderate and severe COVID-19 were characterized by asignificant increase in the level of serum C-reactive protein, an increase in the neutrophil-leukocyte ratio and fibrinogen level, in comparison with data from patients with a mild course of the disease. In mild cases of infection, a moderately negative correlation was revealed between the levels of antibodies to SARS-CoV-2 and NLR. CONCLUSIONS: Detection of antibodies to SARS-CoV-2 in the early stages of hospitalization may be a predictor of a favorable outcome of the disease and serve as an additional criterion for the diagnosis of COVID-19 along with PCR analysis.

A Phase 0 Study to Assess the Biodistribution and Pharmacokinetics of a Radiolabeled Antibody Targeting Human Kallikrein 2 in Participants with Metastatic Castration-Resistant Prostate Cancer.

Despite the inclusion of multiple agents within the prostate cancer treatment landscape, new treatment options are needed to address the unmet need for patients with metastatic castration-resistant prostate cancer (mCRPC). Although prostate-specific membrane antigen is the only cell-surface target to yield clinical benefit in men with advanced prostate cancer, additional targets may further advance targeted immune, cytotoxic, radiopharmaceutical, and other tumor-directed therapies for these patients. Human kallikrein 2 (hK2) is a novel prostate-specific target with little to no expression in nonprostate tissues. This first-in-human phase 0 trial uses an 111In-radiolabeled anti-hK2 monoclonal antibody, [111In]-DOTA-h11B6, to credential hK2 as a potential target for prostate cancer treatment. Methods: Participants with progressive mCRPC received a single infusion of 2 mg of [111In]-DOTA-h11B6 (185 MBq of 111In), with or without 8 mg of unlabeled h11B6 to assess antibody mass effects. Sequential imaging and serial blood samples were collected to determine [111In]-DOTA-h11B6 biodistribution, dosimetry, serum radioactivity, and pharmacokinetics. Safety was assessed within a 2-wk follow-up period from the time of [111In]-DOTA-h11B6 administration. Results: Twenty-two participants received [111In]-DOTA-h11B6 and are included in this analysis. Within 6-8 d of administration, [111In]-DOTA-h11B6 visibly accumulated in known mCRPC lesions, with limited uptake in other organs. Two treatment-emergent adverse events unrelated to treatment occurred, including tumor-related bleeding in 1 patient, which led to early study discontinuation. Serum clearance, biodistribution, and tumor targeting were independent of total antibody mass (2 or 10 mg). Conclusion: This first-in-human study demonstrates that tumor-associated hK2 can be identified and targeted using h11B6 as a platform as the h11B6 antibody selectively accumulated in mCRPC metastases with mass-independent clearance kinetics. These data support the feasibility of hK2 as a target for imaging and hK2-directed agents as potential therapies in patients with mCRPC.

Seroprevalence and levels of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies among medical students

Seroprevalence and levels of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies among medical students

Evaluation of SARS-CoV-2 interferon gamma release assay in BNT162b2 vaccinated healthcare workers.

To predict protective immunity to SARS-CoV-2, cellular immunity seems to be more sensitive than humoral immunity. Through an Interferon-Gamma (IFN-γ) Release Assay (IGRA), we show that, despite a marked decrease in total antibodies, 94.3% of 123 healthcare workers have a positive cellular response 6 months after inoculation with the 2nd dose of BNT162b2 vaccine. Despite the qualitative relationship found, we did not observe a quantitative correlation between IFN-γ and IgG levels against SARS-CoV-2. Using stimulated whole blood from a subset of participants, we confirmed the specific T-cell response to SARS-CoV-2 by dosing elevated levels of the IL-6, IL-10 and TNF-α. Through a 20-month follow-up, we found that none of the infected participants had severe COVID-19 and that the first positive cases were only 12 months after the 2nd dose inoculation. Future studies are needed to understand if IGRA-SARS-CoV-2 can be a powerful diagnostic tool to predict future COVID-19 severe disease, guiding vaccination policies.