Detection, Quantitation, and Characterization of the Major Internal Virion Antigen of the Bovine Leukemia Virus by Radioimmunoassay 2

Abstract

The major internal polypeptide of the bovine leukemia virus (BLV) was purified to homogeneity with the use of gel filtration and affinity chromatography. Like previous results, the protein had a molecular weight of 25,000 daltons as determined by electrophoresis in polyacrylamide gels with sodium dodecyl sulfate. More than 90% of the 125I-labeled protein was precipitated by bovine sera that reacted in immunofluorescence tests with acetone-fixed BLV-infected cells. In contrast, minimal precipitation (less than 5%) was observed with sera from 36 cattle in leukemia-free herds; these sera, negative by immunofluorescence, included six samples that had high titers of antibodies to the foamy-like bovine syncytia virus (BSV). Antisera prepared against several other oncornaviruses or the Mason-Pfizer monkey virus (M-PMV) did not bind the BLV p25 protein. Conversely, the labeled p30 polypeptides of several oncornaviruses tested did not react with bovine sera that had high titers of antibodies to BLV p25. Competitive radioimmunoassay(s) (RIA) also failed to detect cross-reactions between BLV p25 protein and the internal polypeptides of other mammalian and avian oncornaviruses, M-PMV, or foamy-like BSV. The RIA for BLV p25 antigen was also highly sensitive and specific for the detection and quantitation of the antigen in virus preparations and cell homogenates.

Degenerate and specific PCR assays for the detection of bovine leukaemia virus and primate T cell leukaemia/lymphoma virus pol DNA and RNA: phylogenetic comparisons of amplified sequences from cattle and primates from around the world.

“…Cattle were screened for BLV antibodies using radioimmunoassays in which the purified "#&I-labelled major core (p25) or envelope (gp51) BLV proteins were used as antigens (McDonald & Ferrer, 1976 ;Gupta & Ferrer, 1981). Humans and non-human primates were screened for HTLV-I and HTLV-II antibodies using commercial ELISA and Western blot assays (Cellular Products) (Dube et al, 1995).…”

Induction and inhibition of bovine leukaemia virus expression in naturally infected cells

“…Electrophoretically separated proteins were transferred to a nitrocellulose membrane using a Bio-Rad transblot apparatus. The membranes were washed three times for 30 min in MTBS buffer (5% non-fat dry milk, 0.05% Tween 20, and 0-01% antifoam-A emulsion in PBS) and incubated for 1 h at 37 °C with a reference BLV serum appropriately diluted (McDonald & Ferrer, 1976). The filter was washed four times with PBS containing 0.05 % Twean 20 for 30 min and binding of the serum was detected using horseradish peroxidaselabelled rabbit anti-bovine IgG (Jackson Immunoresearch Laboratories).…”

Bovine leukemia virus specific antibodies among French cattle. I. Comparison of complement fixation and hematological tests

“…This observation indicates at least that both the CF test and hematology remain necessary to detect BLV infection. However the development of radioimmuno-assays using the whole virus or purified viral polypeptides (Gilden et a/., 1975;MacDonald and Ferrer, 1976) as antigens will probably allow a more sensitive serological detection. In fact, Devare et al (1976) recently found that 17 of 20 animals belonging to a leukosis herd possessed antibodies to the 1261-labelled BLV-p24.…”