Monkeypox (mpox) is spreading around the world, and its rapid diagnosis is of great significance. In the present study, a rapid and sensitive fluorescent chromatography assisted with cloud system was developed for point-of-care diagnosis of mpox. To screen high affinity antibodies, nanoparticle antigen AaLS-A29 was generated by conjugating A29 onto scaffold AaLS. Immunization with AaLS-A29 induced significantly higher antibody titers and monoclonal antibodies were generated with the immunized mice. A pair of monoclonal antibodies, MXV 14 and MXV 15, were selected for fluorescence chromatography development. The Time-Resolved Fluorescence Immunoassay (TRFIA) was used to develop the chromatography assay. After optimization of the label and concentration of antibodies, a sensitive TRFIA assay with detection limit of 20 pg/mL and good repeatability was developed. The detection of the surrogate Vaccinia virus (VACA) strain Tian Tan showed that the TRFIA assay was more sensitive than the SYBR green I based quantitative PCR. In real samples, the detection result of this assay were highly consistent with the judgement of Quantitative Real-Time PCR (Concordance Rate = 90.48%) as well as the clinical diagnosis (Kappa Value = 0.844, P < 0.001). By combining the portable detection and online cloud system, the detection results could be uploaded and shared, making this detection system an ideal system for point-of-care diagnosis of mpox both in field laboratory and outbreak investigation.

Canine enteric coronavirus (CCV) and canine parvovirus type 2 (CPV-2) are the main pathogens responsible for acute gastroenteritis in dogs, and both single and mixed infections are common. This study aimed to establish a double-labeling time-resolved fluorescence immunoassay (TRFIA) to test and distinguish CCV and CPV-2 diseases.
A sandwich double-labeling TRFIA method was established and optimized using europium(III) (Eu3+)/samarium(III) (Sm3+) chelates. CCV/CPV-2 antigens were first captured by the immobilized antibodies. Then, combined with Eu3+/Sm3+-labeled paired antibodies, the Eu3+/Sm3+ fluorescence values were detected after dissociation to calculate the CCV/CPV-2 ratios. The performance, clinical performance and methodology used for laboratory (sensitivity, specificity, accuracy and stability) testing were evaluated.
A double-label TRFIA for CCV and CPV-2 detection was optimized and established. The sensitivity of this TRFIA kit was 0.51 ng/mL for CCV and 0.80 ng/mL for CPV-2, with high specificity for CCV and CPV-2. All the accuracy data were less than 10%, and the recovery ranged from 101.21 to 110.28%. The kits can be temporarily stored for 20 days at 4 °C and can be stored for 12 months at temperatures less than - 20 °C. Based on a methodology comparison of 137 clinically suspected patients, there was no statistically significant difference between the TRFIA kit and the PCR method. Additionally, for CCV detection, the clinical sensitivity was 95.74%, and the clinical specificity was 93.33%. For CPV-2 detection, the clinical sensitivity was 92.86%, and the clinical specificity was 96.97%.
In this study, a double-label TRFIA kit was prepared for CCV and CPV-2 detection with high laboratory sensitivity, specificity, accuracy, stability, clinical sensitivity and specificity. This kit provides a new option for screening/distinguishing between CCV and CPV-2 and may help improve strategies to prevent and control animal infectious diseases in the future.

Prolactin (PRL) and growth hormone (GH) are two important hormones secreted by the pituitary gland, and their abnormal levels are often related to disease status. This study aimed to establish a new dual-label time-resolved fluorescence immunoassay (TRFIA) to quantitatively measure PRL and GH levels in serum. A sandwich TRFIA was optimized and established: anti-PRL/GH antibodies immobilized on 96-well plates captured PRL/GH and then banded together with anti-PRL/GH paired antibodies labeled with europium(III) (Eu3+)/samarium(III) (Sm3+) chelates. Finally, a time-resolved analyzer measured the Eu3+/Sm3+ fluorescence values. Clinical serum samples were used to evaluate the detection performance of this method. The sensitivities of this dual-label TRFIA were 0.35 ng/mL and 0.45 ng/mL, respectively, and the detection range was between 0.1 and 1000 ng/mL. All the cross-reactivities were lower than 1.07%. The intra-assay and interassay coefficients of variation were 2.18-7.85% and 2.25-7.30%, respectively. Compared with the registered TRFIA kits, a high Pearson coefficient (r = 0.9626 and 0.9675) was observed. This dual-label TRFIA has high sensitivity, accuracy and specificity with good clinical detection performance, representing a suitable alternative to existing methods for determining PRL and GH levels, and is expected to be used in the clinic in the future.

The serum biomarker copeptin, an innovative and stable substitute biomarker of vasopressin, is associated with stroke. Therefore, establishing a highly sensitive time-resolved fluorescence immunoassay for copeptin (copeptin-TRFIA) is helpful to measure stroke and evaluate its value in clinical applications. Double antibody sandwich was used to establish copeptin-TRFIA. The established method was then assessed. Two coated and Eu3+-labeled copeptin monoclonal specific antibodies targeting different antigen epitopes were employed. The serum fluorescence counts of patients with stroke and healthy volunteers were detected by using the well-established copeptin-TRFIA. Serum copeptin levels were measured and analyzed statistically. The actual measurement linearity range of the proposed method was 0.13-44.66 ng/mL. Copeptin-TRFIA had the inter-assay coefficient of variation (CV) of 6.49%-9.08% and the intra-assay CV of 4.75%-7.77%. Patients with cerebral infarction (CI) and intracerebral hemorrhage (ICH) had significantly higher serum copeptin levels than healthy subjects. Copeptin concentrations in the serum of patients with stroke were significantly correlated with the scores of the National Institute for Healthy Stroke Scale (NIHSS) and modified Rankin Scale (mRS). A highly sensitive copeptin-TRFIA was successfully established. Serum copeptin has a certain value in the clinical diagnosis and prognosis of stroke.

This study aimed to establish a highly sensitive time-resolved fluorescence immunoassay of growth stimulating express gene 2 protein (ST2-TRFIA) and evaluate its application value for sepsis.
Two types of ST2 monoclonal specific antibodies against different epitopes of antigen molecule were used as coating and Eu3+-labeled antibodies. The double-antibody sandwich method was used in establishing ST2-TRFIA, and the methodology was evaluated. The established ST2-TRFIA was used in detecting ST2 concentration in the plasma samples of healthy controls and sepsis.
The linear range of ST2-TRFIA was 1.446-500 ng/mL. Plasma ST2 concentrations detected through ST2-TRFIA were consistent with the results of fluorescence quantitative immunochromatography (ρ = 0.946). The plasma ST2 concentrations of patients with sepsis were significantly higher than those of healthy controls (P < 0.01).
This study successfully established a highly sensitive ST2-TRFIA, which was highly comparable to commercially available fluorescent quantitative immunochromatographic kits and can facilitate the timely diagnosis of sepsis.

11-Dehydro-thromboxane B2 (11-dehydro-TXB2) is the final stable metabolite of thromboxane A2 (TXA2) and is involved in thrombus formation. Patients with membranous nephropathy (MN) are prone to thromboembolism events.
Time-resolved fluorescence immunoassay (TRFIA) for 11-dehydro-TXB2 was established by indirect competitive method. The coated 11-dehydro-TXB2-BSA conjugate was used to bind the 11-dehydro-TXB2 antibody competitively to the 11-dehydro-TXB2 antigen in the samples, followed by Eu3+-labeled goat anti-mouse IgG antibody, to detect 11-dehydro-TXB2. This study measured 11-dehydro-TXB2 concentrations in serum samples from healthy individuals and patients with MN.
The linear range of TRFIA was 16.38-2000 pg/mL, the sensitivity was 4.70 pg/mL, the average coefficients of variation from intra-assay and inter-assay were 3.50% and 4.95%, respectively, and the recovery was 99.38%. The serum level of 11-dehydro-TXB2 in patients with MN was significantly higher than that in healthy subjects (P < 0.05). The serum 11-dehydro-TXB2 concentration detected by TRFIA was highly consistent with that by ELISA (ρ = 0.900).
This study successfully established a new highly sensitive method for the detection of 11-dehydro-TXB2 in serum. 11-Dehydro-TXB2 has great potential in evaluating the risk of thromboembolic events in patients with MN and is expected to be applied to other thromboembolic-related diseases.

UNASSIGNED: The present study aimed to evaluate the clinical value of Combined Detection of serum soluble T-cell immunoglobulin 3 (sTim-3) with carcinoembryonic antigen (CEA) or glycotype antigen 19-9 (CA19-9) for Postoperative Recurrence of Colorectal Cancer (CRC) Diagnosis.
UNASSIGNED: The serum sTim-3 was measured by highly sensitivity TRFIA, and serum CEA and CA19-9 were obtained through the collection of clinical data. Quantitative detection of serum sTim-3, CEA, CA19-9 in 90 patients after the CRC surgery (52 postoperative recurrence and 38 no-postoperative recurrence), 21 patients with colorectal benign tumors, and 67 healthy controls. To analyze the clinical diagnostic value of combined detection of sTim-3 with CEA or CA19-9 to test whether patients have recurrence after CRC surgery.
UNASSIGNED: The sTim-3 (15.94±11.24ng/mL) in patients after CRC surgery was significantly higher than in healthy controls (8.95±3.34ng/mL) and colorectal benign tumors (8.39±2.28ng/mL) (P < 0.05), and sTim-3 (20.33±13.04ng/mL) in CRC postoperative recurrent group was significantly higher than in the group without recurrence after CRC surgery (9.94±2.36ng/mL) (P < 0.05). In terms of detecting postoperative recurrence after CRC surgery, combined detection of sTim-3 and CEA (AUC: 0.819, sensitivity: 80.77%, specificity: 65.79%), sTim-3 and CA19-9 test (AUC: 0.813, sensitivity: 69.23%, specificity: 97.30%) was significantly better than the CEA single test (AUC: 0.547, sensitivity: 63.16%, specificity: 48.08%) and CA19-9 single test (AUC: 0.675 sensitivity: 65.38%, specificity: 67.57%), Delong test P < 0.05.
UNASSIGNED: The efficacy of CEA and CA19-9 single test was not optimal, and the combination of sTim-3 in serum could significantly improve the sensitivity and specificity of detecting patient recurrence after CRC surgery.

The effectiveness and necessity of human papillomavirus (HPV) vaccination to prevent HPV infection and cervical cancer are increasingly recognized by people. The 15-valent HPV vaccine, which protects against almost high-risk types of HPV viruses identified by WHO, has attracted much attention. However, as the valence of vaccines increases, quality control in the HPV vaccine production process is facing more challenges. The precise quality control of the HPV type 68 virus-like particles (VLPs), one of the unique components of the 15-valent HPV vaccine that distinguishes it from existing vaccines, is the new requirement for vaccine manufacturers. Here we developed a novel time-resolved fluorescence immunoassay (TRFIA) for rapid and precise automatic quality control of HPV68 VLPs in HPV vaccine. Two murine monoclonal antibodies specifically targeting the HPV68 L1 protein were used to establish a classical sandwich assay. Except for pretreating the vaccine sample, the whole analysis process was performed by a fully automated machine, which saves detection time and gets rid of manual error. Multiple experiments established that the current novel TRFIA can efficiently and reliably analyses HPV68 VLPs. Present novel TRFIA has exhibited merits with speed, robustness, high sensitivity with a minimum detection value of 0.08 ng/mL, considerable accuracy, a wide detection range (up to 1000 ng/mL) and excellent specificity. It is also expected to provide a new detection method for quality control for each HPV type VLPs. To summarize, the novel TRFIA is of great interest for application in HPV vaccine quality control.

Deoxynivalenol (DON) contamination of food crops and feeds is almost impossible to avoid completely; however, through best management practices, this risk can be effectively managed and maximumly mitigated. Accurate and rapid detection of DON contamination as early in the entire value chain as possible is critical. To achieve this goal, we developed a DON test strip based on time-resolved fluorescence immunoassay (TRFIA) and a specific DON monoclonal antibody for the rapid quantification of DON in food crops and feeds. The strip displayed a good linearity (R 2 = 0.9926), with a limit of quantification of 28.16 μg/kg, a wide linear range of 50 ~ 10,000 μg/kg. The intra-batch coefficient of variation (CV) and the inter-batch CV was <5.00 and 6.60%, respectively. This TRFIA-DON test strip was applied to detect DON in real samples, and the accuracy and reliability were confirmed by liquid chromatography-mass spectrometry (LC-MS/MS). Results showed that the relative standard deviation between the DON strips and LC-MS/MS was <9%. The recovery rates in corn samples ranged from 92 to 104%. The established TRFIA-DON test strip had the characteristics of high sensitivity, high accuracy, and a wide linear range which was suitable for rapid and quantitative determination of DON in food crops and feeds at both on-site and laboratory.

This study aimed to establish time-resolved fluorescence immunoassays to quantitatively detect the autoantibodies targeting different epitopes of M-type phospholipase A2 receptor (PLA2R) and evaluate its clinical application in primary membranous nephropathy (PMN).
PLA2R and its reactive epitope-specific IgG/IgG4 time-resolved fluorescence immunoassays (TRFIAs) were established using europium-labeled anti-human IgG/IgG4 antibodies, recombinant proteins, and patient serum. The levels of IgG/IgG4 targeting PLA2R and its epitopes in PMN patient serum were detected, and the relationship between epitope spreading of PLA2R and the severity of patients with PMN was evaluated.
The TRFIAs established in this study could quantitatively detect PLA2R and its epitope-specific IgG and IgG4. Sera from 59 patients with PMN were subjected to detection using anti-PLA2R IgG and anti-PLA2R IgG4. Among them, 46 and 54 patients were found positive for PLA2R antibodies, respectively. Moreover, the levels of PLA2R antibodies were strongly correlated with the severity of patients with PMN. Patients who were detected to have two or more epitopes had more serious renal injury.
PLA2R domain-specific IgG/IgG4 TRFIAs were established in this study, and detection with anti-PLA2R IgG4 could more sensitively screen the reactivity of patients to the PLA2R domain. Moreover, detection epitope spreading of PLA2R was confirmed which is related to the severity of patients with PMN.