Liselotte Pister

Properties of mouse leukemia viruses. I. Characterization of various antisera and serological identification of viral components.

Abstract Six antigenic components of murine leukemia viruses (MuLV) were identified by Ouchterlony tests after degradation of the viruses with Tween 80 and ether. A type-specific antigen (II v ), three gs-species (I, IIgs, and IV), and one gs-interspecies (V) antigen were recognized. The range of viral specificity of a further minor antigen (III) is not yet known. For five MuLV antisera, the reactivity spectra were evaluated by complement fixation, Ouchterlony, and neutralization tests. By Ouchterlony and, preferably, by complement fixation tests, it could be shown that the L cell-virus does not belong to either the FMR or the G type; it apparently is still another serotype of MuLV.

Properties of mouse leukemia viruses: VIII. The major viral glycoprotein of Friend leukemia virus. Seroimmunological, interfering and hemagglutinating capacities

Abstract The purified major glycoprotein (GP 71 ) of Friend leukemia virus revealed type-specific as well as species-specific and interspecies antigenicities in various types of seroimmunological tests. It was also able to induce the production of neutralizing antibodies, to interfere with murine leukemia viruses from two different serotypes, and to hemagglutinate. Demonstration of hemagglutination became possible after reconstitution of GP 71 to multivalent complexes by suitable species-specific antibody (indirect hemagglutination).

Polypeptides of mammalian oncornaviruses: I. Isolation and serological analysis of polypeptides from murine and feline C-type viruses

Abstract Agents representative of murine and feline C-type viruses contain four major polypeptides of molecular weights 10,000 (P1), 12,000 (P2), 15,000 (P3), and 31,000 (P4). Each was shown to contain distinct antigenic determinants. P1 of Friend leukemia virus (FLV) demonstrates species-specific reactivity different from that present in FLV P4. It also seems to be associated with a host cell component. FLV P2 revealed type or subgroup specificity and was shown to be associated with carbohydrate. FLV P3 was not investigated in as much detail. Feline leukemia virus P4, which is known to contain both species and interspecies determinants, revealed also a type-or subgroup-specific reactivity. Finally, an antiserum prepared against murine P4 was shown to contain antibodies directed against distinguishable interspecies determinants.

Studies on mouse leukemia viruses: I. Isolation and characterization of a group-specific antigen

Abstract An antigen specific for mouse leukemia viruses (MLV) was isolated in highly pure form from Friend virus after Tween 80-ether treatment. Its purity was demonstrated by electrophoresis, analytical ultracentrifugation, and serological tests. Serologically identical antigens are present in Rauscher virus as well as Gross virus and a mouse leukemia virus contained in L cell cultures. The group-specific antigen of Friend virus is a strongly basic protein, having a molecular weight of about 26,000 daltons. The amino acid composition of this component was likewise determined.

Properties of mouse leukemia viruses: II. Isolation of viral components

Abstract Three viral substructures were isolated from Tween-ether degraded murine leukemia viruses (MuLV) by Sephadex G-150 chromatography and density gradient centrifugation: a material containing the antigenic determinants IIgs (gs-spec.) and IIv (type specific), a substructure termed component x, and antigen V (gs-inter-spec.). The antigenic determinants IIgs and IIv could not be separated by various methods and are apparently associated with some lipid. This material absorbed neutralizing antibody and possessed hemagglutinating activity when isolated from Friend and Rauscher virus. Component x was demonstrable only by complement fixation tests with complex MuLV antisera. Whether it represents a group- or a type-specific viral antigen could not be decided; however, it did not absorb neutralizing antibody. In the electron microscope, component x preparations consisted of disks with a diameter of about 100 A and filaments formed by aggregation of the disks. Antigen V was isolated from Gross virus. In Ouchterlony tests it demonstrated a reaction of identity with a component of feline leukemia virus. MuLV-antigen I (gs-spec.) could be removed by treatment of the murine viruses with neuraminidase and phospholipase C or less efficiently by treatment with phospholipase C alone. Some of the isolated materials were analyzed by acrylamide gel electrophoresis. The significance of the various components is discussed.

Eine Komplementbindungsreaktion zum Nachweis der bei Leukämieviren verschiedener Säuger vorkommenden gemeinsamen antigenen Komponente

By immunization of a rabbit with purified gs-antigen from mouse leukemia virus (MLV) a potent antiserum (R-gs-serum) was obtained, which reacts specifically with gs-antigen of MLV. In cat leukemia virus (KLV) two types of antigens, probably both group specific, could be demonstrated with anti-KLV-sera by Ouchterlony test. One of these was shown with MLV-sera to be identical with a MLV-gs-antigen component. This antigen occurring in both viruses is called gsinterspecies (interspec.) antigen. R-gs-serum allowed to detect gs-interspec. antigen also by the more sensitive CF-test. [Lispa (leukemia virus interspec. antigen) CF-test]. Preliminary experiments with this test indicated that bovine leukosis as well as human cancer cells can produce an agent in tissue culture which is serologically related to MLV.

Morphological, Chemical, and Antigenic Organization of Mammalian C-Type Viruses

New features in the architecture of mammalian type C viruses, in particular knoblike surface projections and hexagonally arranged subunits on the core shell could be demonstrated by electron microscopy, taking advantage of newly developed preparation techniques. As examples, murine leukemia viruses (MuLVs) and newly isolated porcine and bovine C viruses are presented. The major proteins of a MuLV were isolated and partially characterized in chemical terms and with respect to their serological and other biological activities, such as interfering and hemagglutinating (HA) capacity. Most of the characterized proteins could be localized in particular substructures of the virion either by selective removal or isolation of electron microscopically identifiable constituents. The information obtained allowed the design of a more detailed model of mammalian C viruses. Special attention was devoted to the further characterization of interspecies antigens of mammalian C viruses. Different antigenic determinants were revealed. Their distribution allows further subgrouping of mammalian C viruses.

Nachweis verschiedener antigener Determinanten vom interspecies Typ in RNS-Tumorviren (C-Typ) der Säuger / Evidence for the Existence of Different Antigenic Determinants of the Interspecies Type in Mammalian RNA-C -Type Tumor Viruses

In C-type particles of mammalian origin, two different antigenic determinants of the interspecies type have been revealed by a comparative study of murine-, feline-, suidian-, simian (woolly monkey) (SSV-1)-and RD114-viruses. With respect to the distribution of interspecies determinants, these viruses can be arranged into two distinct groups; one comprises the rodent- and cat-, the other the pig- and monkey-viruses. RD114-virus appears to share a certain non-interspecies antigenic component with cat viruses (strains Rickard and Gardner) but behaves, as far as its interspecies antigenic determinant is concerned, more similar to pig- and woolly monkey-viruses. In showing the serological differences mentioned, IgG antibody could replace whole serum.

Analyse des Vermehrungsmechanismus des Newcastle disease Virus (NDV) mit Hilfe verschiedener Inhibitoren

The reproduction of NDV in chick-embryo-fibroblast cultures was studied with 6-Azauridine, 8-Azaguanine, Parafluorophenylalanine (FPA) and Puromycine as inhibitors. The results suggest that no virus initiated FPA-sensitive material is needed for the uncoating of the infecting particles, and that viral parental RNA is able to induce the formation of protein (s) needed for viral RNA-synthesis (“RNA-protein“) as well as the production of viral structural antigen (s). Further antigenic material appears after the beginning of new viral RNA-synthesis. The “RNA-protein (s)“become (s) detectable between 2 and 3 hours after infection and is (are) stable in its function over several hours. According to the formation of viral antigenic material parental viral RNA can act as a messenger longer than 9 hours. The capacity for the production of hemagglutinating units appears after the viral antigen producing capacity, when viral RNA can already be synthesized. This capacity is separated from that to produce plaque forming particles by a FPA-sensitive phase. The character of the corresponding FPA-sensititve material is unknown.