Detection of the feline leukemia virus and other mammalian oncornaviruses by immunofluorescence

W. D. Hardy, Y. Hirshaut, P. Hess

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An immunofluorescent antibody (IFA) test for detection of the feline leukemia virus (FeLV) was developed. Specific punctate granular cytoplasmic fluorescence was observed with in vivo (kitten) absorbed rabbit antiFeLV gs serum. Fluorescence was seen in only those cells known, by immunodiffusion, to be infected with FeLV. Positive reactions occurred in peripheral leukocytes (granulocytes, lymphocytes), platelets, bone marrow cells (megakaryocytes, lymphoid cells and granulocytes) and tissues from 26 of 30 (86.6%) cats with naturally occurring lymphosarcoma. One of 13 cats with other neoplastic conditions, 4 of 7 cats with feline infectious peritonitis, 2 of 2 cats with myeloproliferative disease and 15 of 110 normal cats were also positive. Of the 15 FeLV positive normal cats, 14 lived in households that had lost a cat with lymphosarcoma or feline infectious peritonitis and 10 lived in households where these cats were FeLV positive. Fluorescence on frozen sections of salivary glands from 6 lymphomatous cats was positive for FeLV, incriminating saliva as the probable vehicle for dissemination of this virus between cats. With this in mind the authors tested 18 owners of FeLV positive cats and 15 veterinarians (high exposure individuals), but were unable to detect FeLV. FeLV was not found in dog, rabbit or human tissues. By immunofluorescence the rabbit antiFeLV gs serum detected the common antigen (gs-3, interspec.) of murine leukemia virus, hamster sarcoma virus and a virus associated with the Novikoff hepatoma of rats. Oncornaviruses of the avian and Russell's viper were negative for this antigen. The IFA test is both extremely sensitive and practical. FeLV gs antigen is stable in smears at room temperature without acetone fixation for 18 mth. Within 4 hr of the preparation of a simple blood smear, the FeLV status of any cat, or other species, can be determined.

Original languageEnglish
Pages (from-to)778-799
Number of pages22
JournalBibliotheca Haematologica
VolumeVol 39
StatePublished - 1973
Externally publishedYes


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