Immunoassay for detection of feline immunodeficiency virus core antigen

The feline immunodeficiency virus (FIV) is a recently identified feline lentivirus that has been found at significant levels in domestic cat populations worldwide. A microdilution plate format, monoclonal antibody-based enzyme-linked immunosorbent assay was developed for the detection of the FIV group-associated antigen (gag) designated p24. Assays of serially diluted samples containing disrupted virus showed that the assay had a sensitivity limit of approximately 0.2 ng/ml for FIV p24. The assay was approximately eightfold more sensitive than the assay for viral reverse transcriptase activity when it was tested with diluted tissue culture samples. A qualitative confirmation assay by standard antibody inhibition techniques was coupled to the screening test methodology. The test was used to detect and confirm the presence of virus in cultured feline lymphocytes from infected animals.