Rapid detection of porcine circovirus type 2 by a red latex microsphere immunochromatographic strip

Abstract

To establish a rapid and specific antigen detection method for porcine circovirus type 2 (PCV2), monoclonal antibodies (mAbs) were produced against the PCV2 epidemic strains and a red latex microsphere immunochromatographic strip was established. A total of eight anti-PCV2b and four anti-PCV2d mAbs were produced, and seven mAbs were confirmed to react with PCV2a, PCV2b, and PCV2d strains using an immunoperoxidase monolayer assay. The results of micro-neutralization tests showed that the mAbs 2C8, 9H4, 10G7, 7B9, and 7C7 had good neutralizing activity, whereas the neutralizing activity of the mAbs 4B3, 4C9, 6H9, and 7E2 was lower than 50%. Three mAbs, 4B3, 7C7, and 9H4, and PCV2 pAb were selected for the establishment of a red latex microsphere immunochromatographic strip, and the combination of mAb 7C7 labeled with red latex microspheres and mAb 9H4 exhibited the greatest detection ability. The immunochromatographic strip had minimum detection limits of 10 2.5 TCID 50 /0.1 ml, 10 0.7 TCID 50 /0.1 ml, and 10 1.5 TCID 50 /0.1 ml for PCV2a/CL, PCV2b/MDJ, and PCV2d/LNHC, respectively. Furthermore, no cross-reactivity was found for African swine fever virus, classical swine fever virus, porcine respiratory and reproductive syndrome virus, porcine parvovirus, porcine pseudorabies virus, porcine circovirus type 1, transmissible gastroenteritis virus, porcine epidemic diarrhea virus, porcine rotavirus, or porcine deltacoronavirus using the immunochromatographic strip. Using PCR as a reference standard, the detection sensitivity, specificity, and overall coincidence rate of the immunochromatographic strip were 81.13%, 100%, and 90.00%. Additionally, the detection ability of the immunochromatographic strip was correlated with that of virus titration. The immunochromatographic strip was used to detect 183 clinical disease samples, and the average positive detection rate was 22.95%. In summary, this method has good sensitivity and specificity and is simple, convenient, and quick to operate. It has high application value for on-site diagnosis of PCV2 and virus quantification. Key points • A red latex microsphere immunochromatographic strip for PCV2 detection was developed . • The method was not only simple to operate, but also takes less time . • The method had good sensitivity and specificity .

Impact of porcine circovirus type 2 on porcine epidemic diarrhea virus replication in the IPI-FX cell line depends on the order of infection

“…PK15 cells (CCL-33) free of PCV1 and PCV2, Vero E6 cells (CRL-1586), IPEC-J2 cells ( Rhoads et al, 1994 ), and IPI-FX cells ( Wang et al, 2019 ) were grown in Dulbecco’s modified Eagle’s medium (DMEM; Invitrogen, Carlsbad, CA, United States) containing 10% heat-inactivated fetal bovine serum (FBS; Gibco, Grand Island, NY, United States). The PCV2a-LG strain (accession number: HM038034), PCV2b-MDJ strain (accession number: OL452025) and PCV2d-LNHC strain (accession number: OL452027) were propagated in PK15 cells ( Yu et al, 2022 ), and the PEDV-SX1a strain was propagated in Vero E6 cells.…”

“…Virus titration was performed as previously described to determine the viral titers of PCV2 in the tissue samples described above ( Yu et al, 2022 ). The sample emulsions were centrifuged at 872 × g for 10 min and sterilized with 0.22 μm filters.…”

Preparation of dyed polymer microspheres by a physical–chemical dual-binding method and their application in lateral flow immunoassay

“…3 The whole immune process is assembled on a membrane, which has the advantages of simple operation, low detection cost, short reaction time and long shelf life. [4][5][6] Therefore, LFIA is widely used in food safety detection, [7][8][9][10] water quality monitoring, 11,12 medical diagnosis [13][14][15][16] and other elds. LFIA usually employs labeled particles to present signals.…”