1887

Journal of General Virology header logo - Volume 62, Issue 2, 1982

Volume 62, Issue 2

Volume 62, Issue 2, 1982

  • Animal

      • Monoclonal Antibody Specific for Avian Sarcoma Virus Structural Protein p27

        https://doi.org/10.1099/0022-1317-62-2-385
        SUMMARY

        A hybridoma cell line which secretes antibody to the Rous sarcoma virus (RSV) structural protein p27 has been established. The hybrid resulted from the fusion of NS-1 myeloma cells with spleen cells from a Balb/c mouse which was immunized with RSV-transformed mouse cells. Antibodies produced by the hybrid clone immunoprecipitated p27 and precursor proteins (Pr180, Pr76 and Pr66) from [S]methionine-labelled chicken embryo fibroblasts transformed by the Schmidt-Ruppin strain of RSV. When Schmidt-Ruppin virus was radioactively labelled with [S]methionine, p27 was the only virus structural protein immunoprecipitated. Antibody production by the hybrid clone (designated 7-29-D6) has remained stable for longer than 12 months at a level of 50 μg IgG/ml medium. A highly sensitive method to determine the subclass specificity of monoclonal antibodies is described. In this procedure, the clone is incubated with [S]-methionine, and radiolabelled antibody is precipitated with affinity-purified, subclass-specific rabbit anti-mouse serum and . The advantages of this procedure are discussed.

    • Persistence of One Species of Oncovirus in Mixed Infection after Antiserum Treatment or Transspecies Rescue

      https://doi.org/10.1099/0022-1317-62-2-393
      SUMMARY

      Attempts were made to change the envelope of murine sarcoma virus (MSV) from B-MuX (a xenotropic murine leukaemia virus isolate) to feline leukaemia virus (FeLV) by infecting cat cells with MSV(B-MuX), adding excess FeLV as helper and using mouse serum oncovirus-inactivating factor or anti-B-MuX serum. In several attempts, virus from single foci of MSV initially contained only MSV(FeLV) but on passage each showed a minimal persistence of B-MuX. To eliminate the B-MuX component, MSV(B-MuX) was subjected to two consecutive transspecies rescues. The first was performed by co-cultivation of MSV(B-MuX)-producing quail cells with mouse 3T3FL cells, which are completely non-permissive for B-MuX, and pure ecotropic Friend Eveline strain of murine leukaemia virus (F-MuLV); this resulted in apparently pure MSV(F-MuLV). Second, these MSV(F-MuLV)-infected 3T3FL cells were co-cultivated with FeLV and cat cells, which are completely nonpermissive for F-MuLV; this resulted in the generation of MSV(FeLV). Passage of this apparently pure FeLV pseudotype in cells permissive only for the replication of B-MuX surprisingly revealed residual murine xenotropic virus. It appears that pressure for survival resulted in genomic masking of B-MuX by heterologous virus envelopes. This phenomenon, which also occurs extensively in nature, implies that if absolute oncovirus genetic purity is required, even extensive attempts at purification may be inadequate.

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  • Plant

      • Translational Competition Between Related Virus RNA Species in Cell-free Systems

        https://doi.org/10.1099/0022-1317-62-2-343
        SUMMARY

        The competition between the RNAs from two tobacco mosaic virus (TMV) strains for translation in rabbit reticulocyte lysate and wheat germ cell-free systems was investigated. The virus translational products were distinguished by the size difference of the I polypeptides. The RNAs of the two strains were translated simultaneously if added to the translation system together at the beginning of the reaction. Each of the TMV RNAs could inhibit translation of the other when the reaction was initiated by the RNA of one strain and that of the other strain was added after active translation had commened. In contrast, translation of alfalfa mosaic virus (AMV) RNA was not appreciably inhibited when its RNA was added after the start of translation of TMV RNA; the addition of TMV RNA to an AMV RNA-initiated reaction also resulted in independent synthesis of the products of both virus RNAs.

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