Heterogeneous Rhodium Single-Atom-Site Catalyst Enables Chemoselective Carbene N-H Bond Insertion.

Transition-metal-catalyzed carbene insertion reactions of a nitrogen-hydrogen bond have emerged as robust and versatile methods for the construction of C-N bonds. While significant progress of homogeneous catalytic metal carbene N-H insertions has been achieved, the control of chemoselectivity in the field remains challenging due to the high electrophilicity of the metal carbene intermediates. Herein, we present an efficient strategy for the synthesis of a rhodium single-atom-site catalyst (Rh-SA) that incorporates a Rh atom surrounded by three nitrogen atoms and one phosphorus atom doped in a carbon support. This Rh-SA catalyst, with a catalyst loading of only 0.15 mol %, exhibited exceptional catalytic performance for heterogeneous carbene insertion with various anilines and heteroaryl amines in combination with diazo esters. Importantly, the heterogeneous catalyst selectively transformed aniline derivatives bearing multiple nucleophilic moieties into single N-H insertion isomers, while the popular homogeneous Rh2(OAc)4 catalyst produced a mixture of overfunctionalized side products. Additionally, similar selectivities for N-H bond insertion with a set of stereoelectronically diverse diazo esters were obtained, highlighting the general applicability of this heterogeneous catalysis approach. On the basis of density functional theory calculations, the observed selectivity of the Rh-SA catalyst was attributed to the insertion barriers and the accelerated proton transfer assisted by the phosphorus atom in the support. Overall, this investigation of heterogeneous metal-catalyzed carbene insertion underscores the potential of single-atom-site catalysis as a powerful and complementary tool in organic synthesis.

Photoinduced Low-Valent Zirconium Catalysis for Cross-Electrophile Coupling of Ethers.

Accessing versatile C(sp3)-C(sp3) bond through the cross-electrophile coupling of two distinct etheric C-O bonds is crucial in organic synthesis but remains barely explored. Herein, we report an innovative photoinduced low-valent zirconocene catalysis enabling the reductive coupling of ethers with high activity and cross-selectivity. Mechanistic investigation suggests that photoexcitation of low-valent zirconocene facilitates the C(sp3)-O bond scission of benzylic ethers, leading to the benzylic radicals intermediate via a single-electron reduction pathway. The subsequent recombination of this benzylic radical with the Zr center followed by carbomagnesiation generates benzylic Grignard reagents for downstream coupling with aliphatic ethers through an SN2-like mechanism. In application, a wide range of ethers readily in situ derived from aldehydes and ketones becomes feasible with high functional group compatibility as well as excellent cross-selectivity.

Identification and validation of circulating biomarkers for detection of liver cancer with antibody array.

The aim of this study was to find new protein biomarkers that could be used to detect hepatocellular carcinoma (HCC) in the serum. We identified 11 proteins in the tissue that could be used to classify samples from HCC and control subjects. The 11 identified tissue biomarkers were combined with 10 commonly used serum HCC biomarkers for further verification in a large number of serum samples from HCC patients and healthy controls. 17 of the 21 prospective serum biomarkers were determined to be differentially expressed through collinearity and significance analysis. Through the method of supervised learning, a random forest model was constructed to reduce the dimensionality of the number of differentially expressed proteins, and finally, 4 differentially expressed proteins were identified: AFP, GDF15, CEACAM-1, and MMP-9, and suggested to have potential application in clinical diagnosis of HCC.

PARD3 gene variation as candidate cause of nonsyndromic cleft palate only.

Nonsyndromic cleft palate only (NSCP) is a common congenital malformation worldwide. In this study, we report a three-generation pedigree with NSCP following the autosomal-dominant pattern. Whole-exome sequencing and Sanger sequencing revealed that only the frameshift variant c.1012dupG [p. E338Gfs*26] in PARD3 cosegregated with the disease. In zebrafish embryos, ethmoid plate patterning defects were observed with PARD3 ortholog disruption or expression of patient-derived N-terminal truncating PARD3 (c.1012dupG), which implicated PARD3 in ethmoid plate morphogenesis. PARD3 plays vital roles in determining cellular polarity. Compared with the apical distribution of wild-type PARD3, PARD3-p. E338Gfs*26 mainly localized to the basal membrane in 3D-cultured MCF-10A epithelial cells. The interaction between PARD3-p. E338Gfs*26 and endogenous PARD3 was identified by LC-MS/MS and validated by co-IP. Immunofluorescence analysis showed that PARD3-p. E338Gfs*26 substantially altered the localization of endogenous PARD3 to the basement membrane in 3D-cultured MCF-10A cells. Furthermore, seven variants, including one nonsense variant and six missense variants, were identified in the coding region of PARD3 in sporadic cases with NSCP. Subsequent analysis showed that PARD3-p. R133*, like the insertion variant of c.1012dupG, also changed the localization of endogenous full-length PARD3 and that its expression induced abnormal ethmoid plate morphogenesis in zebrafish. Based on these data, we reveal PARD3 gene variation as a novel candidate cause of nonsyndromic cleft palate only.

Development and evaluation of time-resolved fluorescent immunochromatographic assay for quantitative detection of SARS-CoV-2 spike antigen.

BACKGROUND: The spread of COVID-19 worldwide caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has necessitated efficient, sensitive diagnostic methods to identify infected people. We report on the development of a rapid 15-minute time-resolved fluorescent (TRF) lateral flow immunochromatographic assay for the quantitative detection of the SARS-CoV-2 spike protein receptor-binding domain (S1-RBD). OBJECTIVES: Our objective was to develop an efficient method of detecting SARS-CoV-2 within 15 min of sample collection. METHODS: We constructed and evaluated a portable, disposable lateral flow device, which detected the S1-RBD protein directly in nasopharyngeal swab samples. The device emits a fluorescent signal in the presence of S1-RBD, which can be captured by an automated TRF instrument. RESULTS: The TRF lateral flow assay signal was linear from 0 to 20 ng/ml and demonstrated high accuracy and reproducibility. When evaluated with clinical nasopharyngeal swabs, the assay was performed at >80% sensitivity, >84% specificity, and > 82% accuracy for detection of the S1-RBD antigen. CONCLUSION: The new S1-RBD antigen test is a rapid (15 min), sensitive, and specific assay that requires minimal sample preparation. Critically, the assay correlated closely with PCR-based methodology in nasopharyngeal swab samples, showing that the detected S1-RBD antigen levels correlate with SARS-CoV-2 virus load. Therefore, the new TRF lateral flow test for S1-RBD has potential application in point-of-care settings.

The attractive effects of amino acids and some classical substances on grass carp (Ctenopharyngodon idellus).

Grass carp (Ctenopharyngodon idellus) is one of the most essential fishing species in China. The bait for this fish is rapidly developing. However, the study on the attractants in the bait for this fish lacks. This study was designed to systematically investigate the effects of 16 kinds of test substances on the perspective of behaviour and physiology of grass carp by using different kinds of methods, including behavioral tests (maze test and biting-balls test) and electro-olfactogram (EOG). Our experiment's idea is mainly to imitate: in addition to vision, fish in nature also use smell to find food and finally swallow under the action of olfaction, taste, and other sensory systems. Firstly, the behavioral maze test was used to screen the attractive or suppressive effect of 16 test substances on grass carp, and the electronic olfactory recording method was used to further evaluate the olfactory response of grass carp to the eight stimuli selected from the maze test. Then, the best concentrations of these eight stimuli and their combination were investigated by the biting-balls test to compound a formula with the strongest appetite for grass carp. The results of behavioral maze test showed that dimethyl-ß-propiothetin (DMPT), dimethylthetin (DMT), glycine, taurine, L-glutamic, L-alanine, L-proline, and L-arginine have different degrees of usefulness in attracting grass carp. The electro-olfactogram recoding showed that the EOG response of grass carp to the stimuli is a transient biphasic potential change and all of the eight stimuli could induce the EOG response of grass carp. The biting-balls test showed that glycine, L-glutamic, and L-arginine at 10-2 mol/L had significant feeding stimulation and DMT at 10-1 mol/L had significant feeding stimulation than the other groups. Finally, formula 9 composed of DMT, glycine, L-glutamic acid, and L-arginine has the greatest attraction for grass carp. The results of this study verified the attractive effect of some amino acids and other chemicals on grass carp fishing, and would provide support for the production of specific grass carp attractants.

A Method for Gray-Scale Imaging of Blood Flow Using High-Frequency Ultrasound.

This paper presents a new method that complements current techniques available in the high-frequency blood imaging field. A comprehensive scattering model was established to determine the feasibility and frequency range of the blood flow imaging of superficial organs and tissues using high-frequency ultrasound. The transmitting and receiving modes and an algorithm were designed to obtain blood flow information based on differentiation between tissues and blood flow. The system was created and tested first with a model that simulates blood flow and was then used on human tissue. A fine-scale image of a blood vessel could be obtained with this system. Moreover, this method can obtain weak blood flow signal using single pulse rather than the traditional pulse-code method and maintains a high resolution that can be matched to high-frequency structural imaging. This study provides a reliable method for further applications related to diagnoses of superficial organs.

[Research of Electronic Sphygmomanometer Intelligent Aeration Based on Pulse Wave Identification].

Through various common domestic and foreign electronic sphygmomanometers to test blood pressure, we find that when measuring high blood pressure or low blood pressure, there is a mismatch between the maximum inflation pressure and the blood pressure measurement, which often results in repeatedly inflating and deflating as well as the problem of high inflation pressure. In order to solve these problems and find a suitable maximum inflation pressure, two intelligent pneumatic solutions based on identifying of pulse wave are suggested and 700 groups of blood pressure experiments are done, then the two solutions are verified by experiments. The experiment proved that these solutions proposed have good stability and accuracy, they can solve the problems appeared in measuring blood pressure effectively, at the same time, the second solution that estimate the maximum inflation pressure during inflation is considered as the best one.

Overexpression of HepaCAM inhibits cell viability and motility through suppressing nucleus translocation of androgen receptor and ERK signaling in prostate cancer.

BACKGROUND: HepaCAM is suppressed in a variety of human cancers, and involved in cell adhesion, growth, migration, invasion, and survival. However, the expression and function of HepaCAM in prostate cancer are still unknown. METHODS: HepaCAM expression has been detected by RT-PCR, Western blotting and immunohistochemistry staining in prostate cell lines RWPE-1, LNCap, DU145, PC3, and in 75 human prostate tissue specimens, respectively. Meanwhile, the cell proliferation ability was detected by WST-8 assay. The role of HepaCAM in prostate cancer cell migration and invasion was examined by wound healing and transwell assay. And flow cytometry was used to observe the apoptosis of prostate cancer cells. Then we detected changes of Androgen Receptor translocation and ERK signaling using immunofluorescence staining and western blot after overexpression of HepaCAM. RESULTS: The HepaCAM expression was significantly down-regulated in prostate cancer tissues and undetected in prostate cancer cells. However, the low HepaCAM expression was not statistically associated with clinicopathological characteristics of prostate cancer. Overexpression of HepaCAM in prostate cancer cells decreased the cell proliferation, migration and invasion, and induced the cell apoptosis. Meanwhile, HepaCAM prevented the androgen receptor translocation from the cytoplasm to the nucleus and down-regulated the MAPK/ERK signaling. CONCLUSION: Our results suggested that HepaCAM acted as a tumor suppressor in prostate cancer. HepaCAM inhibited cell viability and motility which might be through suppressing the nuclear translocation of Androgen Receptor and down-regulating the ERK signaling. Therefore, it was indicated that HepaCAM may be a potential therapeutic target for prostate cancer.

Nuclear factor-κB signaling pathway is involved in phospholipase Cε-regulated proliferation in human renal cell carcinoma cells.

Phospholipase Cε (PLCε), a downstream effector of small GTPase superfamily, has been identified to play a crucial role in tumorigenesis. Previously, our studies have showed that PLCε promotes proliferation of renal cell carcinoma (RCC) cells. However, the molecular mechanisms by which PLCε enhances the survival phenotype of RCC cells are still not fully instructed. In the present study, we first demonstrated that PLCε was highly expressed and had a close correlation with Ki67 protein expression in RCC tissue samples. Further, we found that downregulation of PLCε expression repressed growth and induced apoptosis in RCC cells. In addition, we reported a mechanism by which knockdown of PLCε gene potently suppressed the nuclear factor kappa (NF-κB) signaling pathway through action on inhibitor of κB kinase. Moreover, silencing PLCε gene decreased vascular endothelial growth factor (VEGF) expression, which was a downstream growth factor of NF-κB signaling pathway. Finally, downregulation of VEGF was severely enhanced by treatment cells with NF-κB specific inhibitor BAY11-7028 in PLCε knockdown cells. Taken together, these findings suggest that PLCε promotes RCC cell growth via NF-κB-mediated upregulation of VEGF.

Case report of a novel mutation in the TNC gene in Chinese patients with nonsyndromic hearing loss.

RATIONALE: Hereditary hearing loss is known to exhibit a significant degree of genetic heterogeneity. Herein, we present a case report of a novel mutation in the tenascin-C (TNC) gene in Chinese patients with nonsyndromic hearing loss (NSHL). PATIENT CONCERNS: This includes a young deaf couple and their 2-year-old baby. DIAGNOSES: Based on the clinical information, hearing test, metagenomic next-generation sequencing (mNGS), Sanger sequencing, protein function and structure analysis, and model prediction, in our case, the study results revealed 2 heterozygous mutations in the TNC gene (c.2852C>T, p.Thr951Ile) and the TBC1 domain family member 24 (TBC1D24) gene (c.1570C>T, p.Arg524Trp). These mutations may be responsible for the hearing loss observed in this family. Notably, the heterozygous mutations in the TNC gene (c.2852C>T, p.Thr951Ile) have not been previously reported in the literature. INTERVENTIONS: Avoid taking drugs that can cause deafness, wearing hearing AIDS, and cochlear implants. OUTCOMES: Regular follow-up of family members is ongoing. LESSONS: The genetic diagnosis of NSHL holds significant importance as it helps in making informed treatment decisions, providing prognostic information, and offering genetic counseling for the patient's family.

Ensure the accuracy and consistency of biochemical analyzer test results: Chemometrics for instrument and inter-instrument item comparison in Chinese hospital laboratory.

Biochemical analyzers are vital instruments that utilize the principle of photoelectric colorimetry to quantify a specific chemical composition in body fluids. This analysis provides critical data for the diagnosis, treatment, prognosis, and overall health status of various diseases in clinical practice. However, the performance of a biochemical analyzer can vary significantly between different brands or over time within the same brand. Therefore, it is imperative to regularly assess the performance of the analyzer to ensure consistent results for longitudinal studies and to maintain day-to-day data consistency. Additionally, when multiple analyzers are utilized, it is necessary to evaluate the performance of each instrument to ensure accurate results across multiple platforms. In this study, we developed and verified an experimental evaluation scheme for the analytical performance of the instrument, chemometrics for biochemical analyzers, utilizing national reference materials and patient sera as the experimental subjects. We evaluated the performance of the optical system, temperature control system, sample-adding system, and detection system to confirm the feasibility of this scheme. We also compared the analytical performance of different brands of biochemical analyzers for routine biochemical tests, such as liver function, kidney function, ion, blood lipids, blood glucose, and myocardial enzyme spectrum. Using the AU 5400 as a control and the ADVIA 2400 as the comparison system, the relative variation in inter-instrument comparison data was found to be acceptable at the clinical medicine decision level. In conclusion, the performance of a biochemical analyzer can vary significantly between different brands or over time within the same brand. Regular evaluations are necessary to ensure accurate and consistent results across different analyzers. This study provides a feasible scheme for evaluating the analytical performance of biochemical analyzers that can be used to ensure the accuracy and consistency of the results of different brands of automatic chemical analyzers in the laboratory.

Variant-specific antibody response following repeated SARS-CoV-2 vaccination and infection.

The ongoing emergence of SARS-CoV-2 variants poses challenges to the immunity induced by infections and vaccination. We conduct a 6-month longitudinal evaluation of antibody binding and neutralization of sera from individuals with six different combinations of vaccination and infection against BA.5, XBB.1.5, EG.5.1, and BA.2.86. We find that most individuals produce spike-binding IgG or neutralizing antibodies against BA.5, XBB.1.5, EG.5.1, and BA.2.86 2 months after infection or vaccination. However, compared to ancestral strain and BA.5 variant, XBB.1.5, EG.5.1, and BA.2.86 exhibit comparable but significant immune evasion. The spike-binding IgG and neutralizing antibody titers decrease in individuals without additional antigen exposure, and <50% of individuals neutralize XBB.1.5, EG.5.1, and BA.2.86 during the 6-month follow-up. Approximately 57% of the 107 followed up individuals experienced an additional infection, leading to improved binding IgG and neutralizing antibody levels against these variants. These findings provide insights into the impact of SARS-CoV-2 variants on immunity following repeated exposure.

hepaCAM and p-mTOR closely correlate in bladder transitional cell carcinoma and hepaCAM expression inhibits proliferation via an AMPK/mTOR dependent pathway in human bladder cancer cells.

PURPOSE: We explored the correlation between hepaCAM and activated p-mTOR in bladder transitional cell carcinoma. We also determined whether the antiproliferation effect of hepaCAM is associated with the AMPK/mTOR pathway. MATERIALS AND METHODS: We performed quantitative reverse transcriptase-polymerase chain reaction to determine hepaCAM mRNA expression as well as Western blot to measure hepaCAM and p-mTOR protein levels in 25 men and 5 women. Disease was Ta-T1 in 7 patients, T2-T4 in 23, grade 1 in 13, grade 2 in 9, grade 3 in 8, primary in 13 and recurrent in 17. The WST-8 assay was used to study the effect of hepaCAM on cellular proliferation. p-AMPK, p-mTOR, total AMPK, total mTOR, c-Myc and cyclin D1 were also determined by Western blot. RESULTS: hepaCAM mRNA and protein levels were significantly decreased, while p-mTOR protein was remarkably increased in bladder transitional cell carcinoma compared to adjacent tissues (each p<0.01). Spearman correlation analysis revealed that the hepaCAM decrease was associated with an increase in p-mTOR (r=-0.533, p=0.002). Also, hepaCAM inhibited the proliferation of human bladder transitional cell carcinoma cells. hepaCAM over expression activated AMPK and down-regulated p-mTOR, and its targets c-Myc and cyclin D1. Treatment with the AMPK inhibitor compound C prevented the antiproliferation effect of hepaCAM. Compound C completely blocked hepaCAM induced activation of AMPK and down-regulation of p-mTOR and its targets c-Myc and cyclin D1. CONCLUSIONS: Results suggest an important correlation between hepaCAM and p-mTOR. hepaCAM can inhibit bladder cancer cell proliferation through an AMPK/mTOR dependent pathway.

Long-term effects of Ni(II) on the performance and activity of activated sludge processes.

The long-term effects of Ni(II) on substrate removal and microorganism activities were investigated by operating sequencing batch reactors (SBRs). Compared to the control system lacking Ni(II), the removal efficiencies of total organic carbon (TOC) and ammonium nitrogen (NH4(+)-N) in SBR system loading with 10mgL(-1) Ni(II) decreased drastically from 90.2±3.6 percent to 75.0±8.9 percent, and 99.2±0.6 percent to 50.8±11.5 percent, respectively. As compared to the control system, a inhibitory rate of more than 50 percent for the 2,3,5-triphenyltetrazolium chloride electron transport system (TTC-ETS) and the 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride electron transport system (INT-ETS), and 43 percent for the specific oxygen uptake rate (sOUR) were detected in SBR system loading with 20mgL(-1) Ni(II). TTC-ETS, INT-ETS, and sOUR were significantly correlated with substrate removal efficiencies, suggesting that they could all serve as effective indicators of the performance of activated sludge processes. Additionally, INT-ETS is superior to sOUR and TTC-ETS in detecting the toxic effects of Ni(II) on sludge microorganism activity.

[Influence of hepatocyte cell adhesion molecule on gene expression profile of human bladder transitional cell carcinoma cell line].

OBJECTIVE: To investigate the changes of gene expression file in transitional cell carcinoma of bladder after hepatocyte cell adhesion molecule(hepaCAM) overexpression. METHODS: Affymetrix Human Genome U133 Plus 2.0 Array was used to investigate the changes of gene expression profile between adenovirus-green fluorescent protein(GFP) -hepaCAM group and GFP group in transitional cell carcinoma of bladder EJ cells.Significant Analysis of Microarray(SAM) was used to screen the differentially expressed genes, DAVID software was used to conduct gene ontology analysis and wikiPathway analysis based on the differentially expressed genes. Reverse transcription-polymerase chain reaction and Western blot were applied to verify microarray data. RESULTS: Compared with the GFP group, a total of 2469 genes were up-regulated or down-regulated by more than 2 times in the GFP-hepaCAM group. Among these genes, 1602 genes were up-regulated and 867 were down-regulated.Most of the differentially expressed genes were involved in the function of cell proliferation and cell cycle regulation. The mRNA expressions of nibrin, liver kinase B1, and cyclin D1 detected by reverse transcription-polymerase chain reaction in three different bladder cancer cell lines were consistent with the microarray data.The protein expressions of nibrin and liver kinase B1 in these three cell lines measured by Western blot were consistent with the mRNA expression. CONCLUSIONS: HepaCAM can alter the gene expression profile of bladder cancer EJ cells. The well-known anti-tumor effect of hepaCAM may be mediated by regulating the gene expression via multiple pathways.

[The research of skin imaging technology with high frequency ultrasound].

OBJECTIVE: Developing a high-frequency ultrasonic skin imaging system to obtain the high resolution ultrasonic image of the skin. And further analyzing the ultrasonic images of skin to explore the imaging characteristics of skin structure and then explore the value of high-frequency imaging in the application of skin diagnosis. METHODS: 50 MHz single element ultrasonic transducer, mechanic linear scanning method is used in the imaging system. The resolution and the ability of recognize the skin issue is verified by linear target scanning and clinical trials. RESULTS: Both the axial and lateral resolution of the system reaches 50 microm. The subtle structure of normal skin tissue is clearly visible. Some diseases have obvious appearance in the image. CONCLUSIONS: 50 MHz ultrasonic skin imaging system is of high resolution and is valuable to skin structure detect and disease diagnosis.

A rotation meanout network with invariance for dermoscopy image classification and retrieval.

The computer-aided diagnosis (CAD) system can provide a reference basis for the clinical diagnosis of skin diseases. Convolutional neural networks (CNNs) can not only extract visual elements such as colors and shapes but also semantic features. As such they have made great improvements in many tasks of dermoscopy images. The imaging of dermoscopy has no principal orientation, indicating that there are a large number of skin lesion rotations in the datasets. However, CNNs lack rotation invariance, which is bound to affect the robustness of CNNs against rotations. To tackle this issue, we propose a rotation meanout (RM) network to extract rotation-invariant features from dermoscopy images. In RM, each set of rotated feature maps corresponds to a set of outputs of the weight-sharing convolutions and they are fused using meanout strategy to obtain the final feature maps. Through theoretical derivation, the proposed RM network is rotation-equivariant and can extract rotation-invariant features when followed by the global average pooling (GAP) operation. The extracted rotation-invariant features can better represent the original data in classification and retrieval tasks for dermoscopy images. The RM is a general operation, which does not change the network structure or increase any parameters, and can be flexibly embedded in any part of CNNs. Extensive experiments are conducted on a dermoscopy image dataset. The results show that our method outperforms other anti-rotation methods and achieves great improvements in skin disease classification and retrieval tasks, indicating the potential of rotation invariance in the field of dermoscopy images.

Dermoscopic image retrieval based on rotation-invariance deep hashing.

Dermoscopic image retrieval technology can provide dermatologists with valuable information such as similar confirmed skin disease cases and diagnosis reports to assist doctors in their diagnosis. In this study, we design a dermoscopic image retrieval algorithm using convolutional neural networks (CNNs) and hash coding. A hybrid dilated convolution spatial attention module is proposed, which can focus on important information and suppress irrelevant information based on the complex morphological characteristics of dermoscopic images. Furthermore, we also propose a Cauchy rotation invariance loss function in view of the skin lesion target without the main direction. This function constrains CNNs to learn output differences in samples from different angles and to make CNNs obtain a certain rotation invariance. Extensive experiments are conducted on dermoscopic image datasets to verify the effectiveness and versatility of the proposed module, algorithm, and loss function. Experiment results show that the rotation-invariance deep hashing network with the proposed spatial attention module obtains better performance on the task of dermoscopic image retrieval.

Quantitative Detection of Anti-SARS-CoV-2 Antibodies Using Indirect ELISA.

OBJECTIVE: Real-time reverse transcription-polymerase chain reaction is the gold standard for the diagnosis of COVID-19, but it is necessary to utilize other tests to determine the burden of the disease and the spread of the outbreak such as IgG-, IgM-, and IgA-based antibody detection using enzyme-linked immunosorbent assay (ELISA). MATERIALS AND METHODS: We developed an indirect ELISA assay to quantitatively measure the amount of COVID-19 IgG, IgM, and IgA antibodies present in patient serum, dried blood, and plasma. RESULTS: The population cutoff values for positivity were determined by receiver operating characteristic curves to be 1.23 U/mL, 23.09 U/mL, and 6.36 U/mL for IgG, IgM, and IgA, respectively. After albumin subtraction, the specificity remained >98% and the sensitivity was 95.72%, 83.47%, and 82.60%, respectively, for IgG, IgM, and IgA antibodies to the combined spike subunit 1 receptor binding domain and N proteins in serum. Plasma and dried blood spot specimens were also validated on this assay. CONCLUSION: This assay may be used for determining the seroprevalence of SARS-CoV-2 in a population exposed to the virus or in vaccinated individuals.