Establishment of an indirect ELISA-based method involving the use of a multiepitope recombinant S protein to detect antibodies against canine coronavirus.

Here, we report the development of an indirect enzyme-linked immunosorbent assay (ELISA) method that involves using multiepitope recombinant S protein (rSP) as the coating antigen to detect antibodies against canine coronavirus (CCoV). rSP was designed by arranging its four S fragments (91-135 aa, S1 gene; 377-434 aa, S2 gene; 647-671 aa, S3 gene; 951-971 aa, S4 gene; 207-227 aa) and two T-cell epitopes in tandem: T-E1-E2-E3-E4-T. This multiepitope antigen, which has a molecular weight of approximately 25 kDa and contains a His-tag, was recognized by a CCoV-positive serum in a Western blot assay. The optimal concentration of rSP as a coating antigen in the ELISA was 2 µg/mL, and the optimal dilution of enzyme-labeled secondary antibody was 1:10,000. The cutoff OD450 value was established at 0.2395. No reactivity was observed with antisera against canine distemper virus, canine parvovirus, or feline calicivirus, indicating that this assay is highly specific. We also tested 64 clinical serum samples using our newly established method, and the positive rate was found to be 82.8%. In conclusion, our assay was found to be highly sensitive and specific for the detection of antibodies against CCoV, and it can therefore serve as a new, efficient diagnostic method.

Characteristics of bone metabolism in postmenopausal female patients with different types of idiopathic benign paroxysmal positional vertigo: A single-centre retrospective study.

OBJECTIVE: The association between benign paroxysmal positional vertigo (BPPV) and impaired calcium metabolism has attracted widespread interest. Several studies have suggested that decreased bone mineral density (BMD) and serum 25-hydroxyvitamin D (25(OH)D) level are related to the occurrence and/or recurrence of BPPV; however, the characteristics of bone metabolism in patients with BPPV subtypes have not been fully investigated, and conclusions have been controversial. This study aimed to evaluate BMD and serum levels of 25(OH)D and bone turnover markers to clarify the characteristics of bone metabolism in patients with different types of BPPV. METHOD: We retrospectively analysed the data of new-onset idiopathic postmenopausal female patients with BPPV at our institution from January 2016 to January 2020. The patients' demographic data including age, medication history, concomitant diseases, onset time, clinical form, laboratory indicators, such as serum levels of 25(OH)D, bone formation markers, namely, amino-terminal propeptide of type I procollagen (PINP) and osteocalcin (OC), bone resorption marker, namely, ß-isomerized carboxy-terminal telopeptide of type I collagen (ß-CTX), and BMD were collected and analysed. RESULTS: This study included 201 consecutive postmenopausal female patients with BPPV. Among them, 138 were diagnosed with posterior semicircular canal BPPV, 42 were diagnosed with lateral semicircular canal canalolithiasis, and 21 were diagnosed with lateral semicircular canal cupulolithiasis. There were no significant differences in age distribution, body mass index, clinical history, levels of albumin, globulin, uric acid, creatinine, or blood urea nitrogen, lipid profiles (except high-density lipoprotein cholesterol) and routine blood parameters among these groups (P > 0.05). There were no significant differences in the mean T-score and BMD values of different sites or in the serum levels of 25(OH)D and bone turnover markers (PINP, OC and ß-CTX) among the subgroups (P > 0.05). The proportion of reduction in BMD (T-score < -1 SD) and decreased serum vitamin D level (< 20 ng/ml) were not significantly different between the subgroups (P > 0.05). CONCLUSION: There were no significant differences in bone metabolism in postmenopausal female patients with different types of idiopathic BPPV.