A Combined Method Based on the FIPV N Monoclonal Antibody Immunofluorescence Assay and RT-nPCR Method for the Rapid Diagnosis of FIP-Suspected Ascites

Figure 4

(a) Purification of monoclonal antibody 4B11 by SDS‒PAGE. Lane M, protein marker, lane 1, the purified protein BS8 N. (b) Identification of purified 4B11 antibody by IFA. HEK 293T cells were transfected with the pCMV-MYC-BS8-N. The purified antibody 4B11 was used as the primary antibody for IFA. Scale bar = 75 μm. (c) The detection of FCoV by IFA. FCoV-infected FCWF-4 cells and ascites with infected macrophagocytes were examined by IFA. Samples without infected FIPV were used as a negative control. Red arrows show infected cells. Green fluorescence represents ALexa Fluor® 488 goat antirabbit IgG secondary antibody. Blue fluorescence indicates nuclei stained with DAPI. Scale bar = 100 μm. (d) IHC of the small intestinal epithelium infected with FIP. (1) The small intestine of cats infected with FIPV revealed a positive FIPV antigen reaction in the cytoplasm of small intestinal epithelial cells. (2) Negative control of IHC. The primary antibody used for IHC was an FIPV BS8 N monoclonal antibody. Scale bar = 20 μm.

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