Early polykaryocytosis inhibition: A simple quantitative in vitro assay for the detection of bovine leukemia virus infection in cattle

Guillemain, Bernard; Mamoun, R.; Lévy, Daniel; Astier, T.; Irgens, K; Parodi, André-Laurent

doi:10.1016/0014-2964(78)90097-x

Cited by 12 publications

(5 citation statements)

References 14 publications

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“…on May 10, 2018 by guest http://jvi.asm.org/ with cells displaying the BLV Env protein on the surface (26,29). To account for differences in numbers of cells expressing particular Env variants, the efficiency of syncytium induction ( Fig.…”

Section: Derivation Of Clones Expressing Chimeric Blv Env Proteinsmentioning

confidence: 99%

Envelope Proteins Containing Single Amino Acid Substitutions Support a Structural Model of the Receptor-Binding Domain of Bovine Leukemia Virus Surface Protein

Johnston

Albritton

Radke

2002

J Virol

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Functional domains of the strikingly conserved envelope (Env) glycoproteins of bovine leukemia virus (BLV) and its close relative, human T-cell leukemia virus type 1 (HTLV-1), are still being defined. We have used BLV Env protein variants to gain insights into the structure and function of this important determinant of viral infectivity. Each of 23 different single amino acid variants found in cDNA clones of env transcripts present after short-term culture of peripheral blood mononuclear cells from BLV-infected sheep was expressed in COS-1 cells and tested for the ability to mediate cell fusion and to be cleaved to surface (SU) and transmembrane (TM) protein subunits. Of 11 Env variants that failed to induce syncytia or did so poorly, 7 contained changes in amino acids identical or chemically conserved in the HTLV-1 Env protein. These seven included the four variants that showed aberrant proteolytic cleavage and poor cell surface expression, underscoring their importance for Env structure. Ten of 12 variants that retained wild-type syncytium-inducing ability clustered in the N-terminal half of BLV SU, which forms the putative receptor-binding domain (RBD). Several variants in the RBD showed evidence of subtle misfolding, as judged by reduced binding to monoclonal antibodies recognizing conformational epitopes F, G, and H formed by the N terminus of SU. We modeled the BLV RBD by aligning putative structural elements with known elements of the ecotropic Friend murine leukemia virus RBD monomer. All the variant RBD residues but one are exposed on the surface of this BLV model. These variants as well as function-altering, antibody-reactive residues defined by other investigators group on one face of the molecular model. They are strikingly absent from the opposite face, implying that it is likely to face inward in Env complexes. This surface might interact with the C-terminal domain of SU or with an adjacent monomer in the Env oligomer. This location suggests an orientation for the monomer of ecotropic Friend murine leukemia virus RBD.Envelope (Env) proteins confer infectivity on retroviral particles. Oligomers of these proteins bind to receptors on the surfaces of host cells and mediate entry of the viral genome into the cell. The Env protein complex is composed of surface glycoprotein (SU) subunits, which are anchored to virions by their association with transmembrane (TM) protein subunits. SU molecules recognize and bind to cellular receptors, thereby initiating a complex series of conformational changes that lead to fusion of viral and cellular membranes by TM oligomers (reviewed in reference 30). Upon successful synthesis of the DNA provirus and its integration into host cell DNA, expression of viral genes ensues. When the newly synthesized polyprotein Env precursor is cleaved in the Golgi apparatus of the virus-producing host cell, SU and TM subunits remain associated in a metastable state (18). Oligomers of mature Env proteins are transported to the cell surface membrane, where they can be incorporated into b...

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Section: Derivation Of Clones Expressing Chimeric Blv Env Proteinsmentioning

confidence: 99%

Envelope Proteins Containing Single Amino Acid Substitutions Support a Structural Model of the Receptor-Binding Domain of Bovine Leukemia Virus Surface Protein

Johnston

Albritton

Radke

2002

J Virol

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“…The relationship between syncytial effect and BLV expression was examined by several investigators; late effects of BLV infection (4 to 8 days) were used to titrate the infectivity of BLV as well as to determine, in neutralization tests, the presence of BLV antibodies in the sera of infected cattle (Ferrer & Diglio, 1976;Van Der Maaten & Miller, 1977;Benton et aL, 1978). In contrast, early (24 h) and extensive polykaryocytosis induced by BLV in cat cells co-cultured with BLV-infected cells was used to quantify infected cells (Guillemain et aL, 1977a) and BLV-induced antibodies (Guillemain et al, 1977bOgura et aL, 1977;Greig et al, 1978). A recent investigation (Onuma et aL, 1980) showed that BLV itself could induce either early (24 h) or late polykaryocytosis (as defined by Poste, 1970), dePending on the dose.…”

mentioning

confidence: 99%

Mechanisms of Early and Late Polykaryocytosis Induced by the Bovine Leukaemia Virus

Guillemain

Mamoun

Astier

et al. 1981

Journal of General Virology

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SUMMARYSyncytia formation induced by the bovine leukaemia virus (BLV) has been classified as 'early' or 'late' polykaryocytosis. Early polykaryocytosis arises in the first 24 h in mixed cultures of BLV-infected cells with indicator cells. Late polykaryocytosis is observed 4 to 8 days after infection of sensitive cells with cell-free infectious BLV. Our results demonstrate that the two phenomena proceed from different mechanisms. Late polykaryocytosis results from an active process dependent on the integrity of the virus genome. In contrast, early polykaryocytosis is a passive process which does not require any de novo virus synthesis but is dependent on the presence of virus proteins in inducer cells.

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“…Bovine leukemia virus (BLV) induces syncytia formation in various species of embryonic cells as well as transformed cell lines (2,4,8,12). In the previous paper, we have described the two types of syncytia formation induced by BLV (11).…”

Section: Introductionmentioning

confidence: 99%

“…These types of syncytia formation were inhibited by the addition of anti-BLV serum, while sera from serologically negative cattle were not (1i, 12). Early syncytia inhibition (ESI) test was conducted for the detection of BLV antibody (3,4).…”

Section: Introductionmentioning

confidence: 99%

Enhancement of antibody activity to bovine leukemia virus by complement

Watarai¹,

Onuma

Mikami

et al. 1981

Archives of Virology

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Cocultivation of fetal lamb kidney cells infected with bovine leukemia virus (BLV) and the cat cells containing murine sarcoma virus genome resulted in the rapid production of syncytia. This syncytia formation was inhibited by serum containing antibodies to glycoprotein antigen of BLV. When rabbit complement was added to the antiserum for early syncytia inhibition (ESI) test, a significant enhancement of ESI activity of the antiserum was observed. This enhancement was associated with IgG fraction but not with IgM fraction of the antiserum. The results of the comparative serological tests showed that the ESI test with complement was much more sensitive than either immunodiffusion or complement fixation tests in the detection of BLV antibodies.

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Early polykaryocytosis inhibition: A simple quantitative in vitro assay for the detection of bovine leukemia virus infection in cattle

Cited by 12 publications

References 14 publications

Envelope Proteins Containing Single Amino Acid Substitutions Support a Structural Model of the Receptor-Binding Domain of Bovine Leukemia Virus Surface Protein

Envelope Proteins Containing Single Amino Acid Substitutions Support a Structural Model of the Receptor-Binding Domain of Bovine Leukemia Virus Surface Protein

Mechanisms of Early and Late Polykaryocytosis Induced by the Bovine Leukaemia Virus

Enhancement of antibody activity to bovine leukemia virus by complement

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