Ultrastructural expression of virus-like particles in human leukaemic cells growing in vitro

The assembly of a hexameric lattice of retroviral immature particles requires the involvement of cell factors such as proteins and small molecules. A small, negatively charged polyanionic molecule, myo-inositol hexaphosphate (IP6), was identified to stimulate the assembly of immature particles of HIV-1 and other lentiviruses. Interestingly, cryo-electron tomography analysis of the immature particles of two lentiviruses, HIV-1 and equine infectious anemia virus (EIAV), revealed that the IP6 binding site is similar. Based on this amino acid conservation of the IP6 interacting site, it is presumed that the assembly of immature particles of all lentiviruses is stimulated by IP6. Although this specific region for IP6 binding may be unique for lentiviruses, it is plausible that other retroviral species also recruit some small polyanion to facilitate the assembly of their immature particles. To study whether the assembly of retroviruses other than lentiviruses can be stimulated by polyanionic molecules, we measured the effect of various polyanions on the assembly of immature virus-like particles of Rous sarcoma virus (RSV), a member of alpharetroviruses, Mason-Pfizer monkey virus (M-PMV) representative of betaretroviruses, and murine leukemia virus (MLV), a member of gammaretroviruses. RSV, M-PMV and MLV immature virus-like particles were assembled in vitro from truncated Gag molecules and the effect of selected polyanions, myo-inostol hexaphosphate, myo-inositol, glucose-1,6-bisphosphate, myo-inositol hexasulphate, and mellitic acid, on the particles assembly was quantified. Our results suggest that the assembly of immature particles of RSV and MLV was indeed stimulated by the presence of myo-inostol hexaphosphate and myo-inositol, respectively. In contrast, no effect on the assembly of M-PMV as a betaretrovirus member was observed.

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Some ‘in vitro’ effects of bacterial filtrates on normal lymphocytes and leukaemic cells

Irish Journal of Medical Science (1971 -) ◽

10.1007/bf02939025 ◽

1975 ◽

Vol 144 (1) ◽

pp. 266-273

Author(s):

Joyce de Azavedo ◽

J. F. Greally

Keyword(s):

Leukaemic Cells ◽

In Vitro Effects

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A Conformational Transition Observed in Single HIV-1 Gag Molecules during In Vitro Assembly of Virus-Like Particles

Journal of Virology ◽

10.1128/jvi.03353-13 ◽

2014 ◽

Vol 88 (6) ◽

pp. 3577-3585 ◽

Cited By ~ 33

Author(s):

J. B. Munro ◽

A. Nath ◽

M. Farber ◽

S. A. K. Datta ◽

A. Rein ◽

...

Keyword(s):

Conformational Transition ◽

Virus Like Particles ◽

In Vitro Assembly ◽

Hiv 1

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Conjugation of an antibody Fv fragment to a virus coat protein: cell-specific targeting of recombinant polyoma-virus-like particles

Biochemical Journal ◽

10.1042/bj3560867 ◽

2001 ◽

Vol 356 (3) ◽

pp. 867-873 ◽

Cited By ~ 20

Author(s):

Kay STUBENRAUCH ◽

Stefan GLEITER ◽

Ulrich BRINKMANN ◽

Rainer RUDOLPH ◽

Hauke LILIE

Keyword(s):

Coat Protein ◽

Mammalian Cells ◽

Recombinant Antibody ◽

Specific Antigen ◽

Antibody Fragment ◽

Fusion Peptides ◽

Virus Like Particles ◽

Vector Systems ◽

Virus Coat

The development of cell-type-specific delivery systems is highly desirable for gene-therapeutic applications. Current virus-based vector systems show broad cell specificity, which results in the need to restrict the natural tropism of these viral systems. Here we demonstrate that tumour-cell-specific virus-like particles can be functionally assembled in vitro from recombinant viral coat protein expressed in Escherichia coli. The insertion of a negatively charged peptide in the HI loop of polyoma VP1 interferes with the binding of VP1 to the natural recognition site on mammalian cells and also serves as an adapter for the coupling of antibody fragments that contain complementary charged fusion peptides. A recombinant antibody fragment of the tumour-specific anti-(Lewis Y) antibody B3 could be coupled to the mutant VP1 by engineered polyionic peptides and an additional disulphide bond. With this system an entirely recombinant cell-specific delivery system assembled in vitro could be generated that transfers genes preferentially to cells presenting the tumour-specific antigen on the cell surface.

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Interaction of normal haemopoiesis and L5222 leukaemic cells in vivo and in vitro

Leukemia Research ◽

10.1016/0145-2126(77)90015-7 ◽

1977 ◽

Vol 1 (2-3) ◽

pp. 145-147 ◽

Cited By ~ 2

Author(s):

D. Hoelzer ◽

E.B. Harriss ◽

E. Kurrle

Keyword(s):

Leukaemic Cells

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Growth in vivo of l5178y-r murine leukaemic cells treated in vitro with cis-dichloro bis-(cyclopentylamine) platinum II

British Journal of Cancer ◽

10.1038/bjc.1981.18 ◽

1981 ◽

Vol 43 (1) ◽

pp. 116-117 ◽

Cited By ~ 2

Author(s):

I Szumiel ◽

E Niepokojczycka ◽

E Godlewska

Keyword(s):

Leukaemic Cells

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The Retroviral Capsid Domain Dictates Virion Size, Morphology, and Coassembly of Gag into Virus-Like Particles

Journal of Virology ◽

10.1128/jvi.79.21.13463-13472.2005 ◽

2005 ◽

Vol 79 (21) ◽

pp. 13463-13472 ◽

Cited By ~ 69

Author(s):

Danso Ako-Adjei ◽

Marc C. Johnson ◽

Volker M. Vogt

Keyword(s):

Nuclear Export ◽

Leukemia Virus ◽

Particle Diameter ◽

Particle Morphology ◽

Structural Protein ◽

Wild Type ◽

Virus Like Particles ◽

Gag Proteins ◽

Hiv 1

ABSTRACT The retroviral structural protein, Gag, is capable of independently assembling into virus-like particles (VLPs) in living cells and in vitro. Immature VLPs of human immunodeficiency virus type 1 (HIV-1) and of Rous sarcoma virus (RSV) are morphologically distinct when viewed by transmission electron microscopy (TEM). To better understand the nature of the Gag-Gag interactions leading to these distinctions, we constructed vectors encoding several RSV/HIV-1 chimeric Gag proteins for expression in either insect cells or vertebrate cells. We used TEM, confocal fluorescence microscopy, and a novel correlative scanning EM (SEM)-confocal microscopy technique to study the assembly properties of these proteins. Most chimeric proteins assembled into regular VLPs, with the capsid (CA) domain being the primary determinant of overall particle diameter and morphology. The presence of domains between matrix and CA also influenced particle morphology by increasing the spacing between the inner electron-dense ring and the VLP membrane. Fluorescently tagged versions of wild-type RSV, HIV-1, or murine leukemia virus Gag did not colocalize in cells. However, wild-type Gag proteins colocalized extensively with chimeric Gag proteins bearing the same CA domain, implying that Gag interactions are mediated by CA. A dramatic example of this phenomenon was provided by a nuclear export-deficient chimera of RSV Gag carrying the HIV-1 CA domain, which by itself localized to the nucleus but relocalized to the cytoplasm in the presence of wild type HIV-1 Gag. Wild-type and chimeric Gag proteins were capable of coassembly into a single VLP as viewed by correlative fluorescence SEM if, and only if, the CA domain was derived from the same virus. These results imply that the primary selectivity of Gag-Gag interactions is determined by the CA domain.

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Chimeric virus-like particles of universal antigen epitopes of coronavirus and phage Qβ coat protein trigger the production of neutralizing antibodies

Current Topics in Medicinal Chemistry ◽

10.2174/1568026621666210618145411 ◽

2021 ◽

Vol 21 ◽

Author(s):

Yukun Guo ◽

Ruizhen Guo ◽

Yingxian Ma ◽

Wenru Chang ◽

Shengli Ming ◽

...

Keyword(s):

Coat Protein ◽

Neutralizing Antibodies ◽

Vaccine Development ◽

Genetic Recombination ◽

Fluorescent Label ◽

Salting Out ◽

Virus Like Particles ◽

Chimeric Vlps ◽

Universal Epitope

Background: Virus-like particles (VLPs) are non-genetic multimeric nanoparticles synthesized through in vitro or in vivo self-assembly of one or more viral structural proteins. Immunogenicity and safety of VLPs make them ideal candidates for vaccine development and efficient nanocarriers for foreign antigens or adjuvants to activate the immune system. Aims: The present study aimed to design and synthesize a chimeric VLP vaccine of the phage Qbeta (Qβ) coat protein presenting the universal epitope of the coronavirus. Methods: The RNA phage Qβ coat protein was designed and synthesized, denoted as Qbeta. The CoV epitope, a universal epitope of coronavirus, was inserted into the C-terminal of Qbeta using genetic recombination, which was designated as Qbeta-CoV. The N-terminal of Qbeta-CoV was successively inserted into the TEV restriction site using mCherry red fluorescent label and modified affinity-purified histidine label 6xHE, which was denoted as HE-Qbeta-CoV. Isopropyl β-D-1-thiogalactopyranoside (IPTG) assessment revealed the expression of Qbeta, Qbeta-CoV, and HE-Qbeta-CoV in the BL21 (DE3) cells. The fusion protein was purified by salting out using ammonium sulfate and affinity chromatography. The morphology of particles was observed using electron microscopy. The female BALB/C mice were immunized intraperitoneally with the Qbeta-CoV and HE-Qbeta-CoV chimeric VLPs vaccines. Their sera were collected for the detection of antibody level and antibody titer using ELISA. The serum is used for the neutralization test of the three viruses of MHV, PEDV, and PDCoV. Results: The results revealed that the fusion proteins Qbeta, Qbeta-CoV, and HE-Qbeta-CoV could all obtain successful expression. Particles with high purity were obtained after purification; the chimeric particles of Qbeta-CoV and HE-Qbeta-CoV were found to be similar to Qbeta particles in morphology and formed chimeric VLPs. In addition, two chimeric VLP vaccines induced specific antibody responses in mice, and the antibodies showed certain neutralizing activity. Conclusion: The successful construction of the chimeric VLPs of the phage Qβ coat protein presenting the universal epitope of coronavirus provides a vaccine form with potential clinical applications for the treatment of coronavirus disease.

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A Novel MVA-Based HIV Vaccine Candidate (MVA-gp145-GPN) Co-Expressing Clade C Membrane-Bound Trimeric gp145 Env and Gag-Induced Virus-Like Particles (VLPs) Triggered Broad and Multifunctional HIV-1-Specific T Cell and Antibody Responses

Viruses ◽

10.3390/v11020160 ◽

2019 ◽

Vol 11 (2) ◽

pp. 160 ◽

Cited By ~ 4

Author(s):

Beatriz Perdiguero ◽

Cristina Sánchez-Corzo ◽

Carlos Sorzano ◽

Lidia Saiz ◽

Pilar Mediavilla ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Vaccine Candidate ◽

Hiv Vaccine ◽

Replication Capacity ◽

Virus Like Particles ◽

Modified Vaccinia Virus Ankara ◽

Clade C ◽

Membrane Bound ◽

Hiv 1

The development of an effective Human Immunodeficiency Virus (HIV) vaccine that is able to stimulate both the humoral and cellular HIV-1-specific immune responses remains a major priority challenge. In this study, we described the generation and preclinical evaluation of single and double modified vaccinia virus Ankara (MVA)-based candidates expressing the HIV-1 clade C membrane-bound gp145(ZM96) trimeric protein and/or the Gag(ZM96)-Pol-Nef(CN54) (GPN) polyprotein that was processed to form Gag-induced virus-like particles (VLPs). In vitro characterization of MVA recombinants revealed the stable integration of HIV-1 genes without affecting its replication capacity. In cells that were infected with Env-expressing viruses, the gp145 protein was inserted into the plasma membrane exposing critical epitopes that were recognized by broadly neutralizing antibodies (bNAbs), whereas Gag-induced VLPs were released from cells that were infected with GPN-expressing viruses. VLP particles as well as purified MVA virions contain Env and Gag visualized by immunoelectron microscopy and western-blot of fractions that were obtained after detergent treatments of purified virus particles. In BALB/c mice, homologous MVA-gp145-GPN prime/boost regimen induced broad and polyfunctional Env- and Gag-specific CD4 T cells and antigen-specific T follicular helper (Tfh) and Germinal Center (GC) B cells, which correlated with robust HIV-1-specific humoral responses. Overall, these results support the consideration of MVA-gp145-GPN vector as a potential vaccine candidate against HIV-1.

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