scholarly journals Engineered Retroviruses as Fluorescent Biological Reference Particles for Small Particle Flow Cytometry

2019 ◽  
Author(s):  
Vera A. Tang ◽  
Anna K. Fritzsche ◽  
Tyler M. Renner ◽  
Dylan Burger ◽  
Edwin van der Pol ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Size Range ◽  
Limit Of Detection ◽  
Leukemia Virus ◽  
Small Particles ◽  
Phenotypic Analysis ◽  
Biological Particles ◽  
Nanometer Size Range ◽  
Antibody Labeling ◽  
Murine Leukemia

ABSTRACTThere has been renewed interest in the use of flow cytometry for single particle phenotypic analysis of particles in the nanometer size-range such as viruses, organelles, bacteria and extracellular vesicles (EVs). However, many of these particles are smaller than 200 nm in diameter, which places them at the limit of detection for many commercial flow cytometers. The use of reference particles of diameter, fluorescence, and light-scattering properties akin to those of the small biological particles being studied is therefore imperative for accurate and reproducible data acquisition and reporting across different instruments and analytical technologies. We show here that an engineered murine leukemia virus (MLV) can act as a fluorescence reference particle for other small particles such as retroviruses and EVs. More specifically, we show that engineered MLV is a highly monodisperse enveloped particle that can act as a surrogate to demonstrate the various effects of antibody labeling on the physical properties of small biological particles in a similar diameter range.

Particle adhesion: interaction forces and mechanical effects: extrapolation to the nanometer-size range

1997 ◽  
Vol 501 ◽  
Author(s):  
D. S. Rimai ◽  
L. P. Demejo ◽  
B. Gady ◽  
D. J. Quesnel ◽  
R. C. Bowen ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Size Range ◽  
Particle Adhesion ◽  
Small Particles ◽  
Interaction Forces ◽  
Plastic Deformations ◽  
Nanometer Size ◽  
Nanometer Size Range ◽  
Micrometer Size ◽  
Complex Subject

ABSTRACTThe physics of particle adhesion is a complex subject and depends on the interaction mechanisms and the mechanical properties of the contacting materials. These interactions, which tend to be caused by van der Waals and electrostatic interactions, generate stresses that, in turn, result in deformations of the contacting materials. Most of today's understanding of particle adhesion is based on theories that assume that the adhesion-induced strains are small. However, for small particles, the strains can be quite large, resulting in yielding and plastic deformations. In some instances, the entire particle can become engulfed by the substrate. This paper discusses the nature of the deformations, as are presently known, and extrapolates today's understanding of particle adhesion, which is based on the micrometer-size scale, to nanometer-size particles.

Recent Studies on a Murine Leukemia Virus Grown in Tissue Culture

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.

Immunoferritin Labelling of Murine Leukemia Virus Antigens in thin Sections

1980 ◽  
Vol 38 ◽  
pp. 508-509
Author(s):  
Ray A. Weigand ◽  
Gregory C. Varjabedian
Keyword(s):  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Intracellular Localization ◽  
Uranyl Acetate ◽  
Antibody Technique ◽  
Thin Sections ◽  
Tumor Virus ◽  
Labelling Procedure ◽  
Unlabelled Antibody ◽  
Murine Leukemia

We previously described the intracellular localization of murine mammary tumor virus (MuMTV) p28 protein in thin sections (1). In that study, MuMTV containing cells fixed in 3% paraformaldehyde plus 0.05% glutaraldehyde were labelled after thin sectioning using ferritin-antiferritin in an unlabelled antibody technique. We now describe the labelling of murine leukemia virus (MuLV) particles using the unlabelled antibody technique coupled to ferritin-Fab antiferritin. Cultures of R-MuLV in NIH/3T3 cells were grown to 90% confluence (2), fixed with 2% paraformaldehyde plus 0.5% glutaraldehyde in 0.1 M cacodylate at pH 7.2, postfixed with buffered 17 OsO4, dehydrated with a series of etha-nols, and embedded in Epon. Thin sections were collected on nickel grids, incubated in 107 H2O2, rinsed in HEPES buffered saline, and subjected to the immunoferritin labelling procedure. The procedure included preincubation in 27 egg albumin, a four hour incubation in goat antisera against purified gp69/71 of MuLV (3) (primary antibody), incubation in F(ab’)2 fragments of rabbit antisera to goat IgG (secondary antibody), incubation in apoferritin, incubation in ferritin-Fab ferritin, and a brief fixation with 2% glutaraldehyde. The sections were stained with uranyl acetate and examined in a Siemens IA electron microscope at an accelerating voltage of 60 KV.

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