T-lymphocyte priming and protection against Friend leukemia by vaccinia-retrovirus env gene recombinant

Friend murine leukemia virus complex (FV)-induced immunosuppression was studied by assaying splenic anti-SRBC PFC responses and plasma antibody titers in mice at various times after FV inoculation. Genes located within the H-2 complex were found to influence resistance to FV-induced immunosuppression. Near normal responses were observed in mice having the H-2a/b or H-2b/b genotype, whereas mice having the H-2a/a genotype were suppressed. This H-2 effect was observed not only in mice having heterozygous C57BL/10 X A background genes, including Rfv-3r/s, but also was apparent in mice having homozygous A-strain background genes, including Rfv-3s/s. Therefore, the Rfv-3 gene did not appear to convey resistance to FV-induced immunosuppression. The suppression in susceptible H-2a/a mice was characterized by a partial suppression of the IgM response and a profound suppression of both the primary and secondary IgG responses. Neither splenomegaly nor viremia alone appeared to be sufficient for the induction or maintenance of the immunosuppression. The mechanism of suppression was unclear, but both B lymphocyte and T lymphocyte functions appeared to be altered.

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Recent Studies on a Murine Leukemia Virus Grown in Tissue Culture

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100060544 ◽

1967 ◽

Vol 25 ◽

pp. 106-107

Author(s):

L. Z. de Tkaczevski ◽

E. de Harven ◽

C. Friend

Keyword(s):

Tissue Culture ◽

Solid Tumors ◽

Murine Leukemia Virus ◽

Leukemia Virus ◽

Supernatant Fluid ◽

Virus Particles ◽

Friend Leukemia ◽

Type C ◽

Leukemia Viruses ◽

Murine Leukemia

Despite extensive studies, the correlation between the morphology and pathogenicity of murine leukemia viruses (MLV) has not yet been clarified. The virus particles found in the plasma of leukemic mice belong to 2 distinct groups, 1 or 2% of them being enveloped A particles and the vast majority being of type C. It is generally believed that these 2 types of particles represent different phases in the development of the same virus. Particles of type A have been thought to be an earlier form of type C particles. One of the tissue culture lines established from Friend leukemia solid tumors has provided the material for the present study. The supernatant fluid of the line designated C-1A contains an almost pure population of A particles as illustrated in Figure 1. The ratio is, therefore, the reverse of what is unvariably observed in the plasma of leukemic mice where C particles predominate.

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Involvement of GER in Friend leukemia virus assembly in high-pressure frozen cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160509 ◽

1990 ◽

Vol 48 (3) ◽

pp. 590-591

Author(s):

W. Djaczenko ◽

M. Müller ◽

A. Benedetto ◽

G. Carbone

Keyword(s):

High Pressure ◽

Virus Assembly ◽

Leukemia Virus ◽

Leukemia Cells ◽

Serial Sections ◽

Myeloma Cells ◽

Virus Particles ◽

Friend Leukemia ◽

Carbon Coated ◽

Friend Leukemia Virus

A thickening of ER membranes in murine myeloma cells was attributed by de Harven to the assembly of intracisternal virus particles. We observed similar thickening of GER membranes in Friend leukemia cells (FLC) apparently associated with Friend leukemia virus (FLV) assembly. We reinvestigated the problem of GER involvement in FLV assembly using high pressure cryofixed FLC.FLC (745A clone growing in suspension and FF clone growing in monolayer) were immersed in Hexadecene (Fluka, Switzerland) and rapidly frozen in Balzers HPM 010 freezing machine working at 2200 bar. All cells were freeze substituted at -90°C in 2% OsO4 in absolute acetone. Serial sections cut to avoid misinterpretations due to the geometry of sections, were collected on carbon coated 100 mesh grids.

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