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PubMedDate not supplied

[Effect of temperature on the infectivity of the iridovirus and densonucleosis virus of blood-sucking mosquitoes].

Mosquito densonucleosis virus and iridovirus were used to study the influence of temperature on their infectivity. Biological assays of mosquito densonucleosis virus were carried out in larvae of I-II instar of Aedes aegypti mosquitoes, those of mosquito iridovirus in larvae of Galleria mellonella. The rate of inactivation was found to be directly dependent on the dose of the heat treatment. Treatment at 60 degrees C led to complete loss of iridovirus infectivity; the virus activity declined considerably after treatment at 50 degrees and 40 degrees C for 60 min. Mosquito densonucleosis virus infectivity was eliminated completely at 65 degrees C. The decline of infectivity of both viruses was intermittent.

Aedes↗
PubMed1977

[Interactions between nuclear polyhedrosis viruses and vertebrate cells (author's transl)].

The influence of NPV on mammals was tested in animals and tissue cultures. Toxicity experiments were performed in rats: per os application (3 X 10(9) Virusinclusionbodies per kg body weight) and intravenous (5 X 10(8) Virusinclusionbodies per kg body weight). Skin irrition was performed in guinea pigs. In each tested animal no virus induced changes could be shown. Tissue culture studies were done in tissues of human (Hela Ohio), monkey (Vero) and rats (REC). The infectious unit was Ac NPV derived from infected, virus-producing insect tissue cultures. Three blind passages were done in each examined cell type and no signs of viral replication could be shown. An additional infectivity assay of cellfree extracts in insect cell cultures as indicator system remained negative.

Animals↗
PubMed1975

[Virus disease complexes: transmissible pathological entities in invertebrates].

Virus disease complexes of Galleria mellonella L. due respectively to a Parvovirus with a Baculovirus and a Parovirus with an Iridovirus have been transmitted to healthy larvae by ingestion of corpses of larvae affected by these disease complexes. The histological and cytological injuries observed are identical to those noted during the study of the initial complexes.

Adipose Tissue↗
PubMed1993

Expression of simian type D retroviral (Mason-Pfizer monkey virus) capsids in insect cells using recombinant baculovirus.

Mason-Pfizer monkey virus (M-PMV) is a primate retrovirus that shows type D morphogenesis in mammalian cells. Immature intracytoplasmic A type particles (ICAPs) preassemble in the infected cell cytoplasm migrate to the plasma membrane and are released by budding. This is in contrast to retroviruses that show type C morphogenesis, where assembly and budding occur concurrently at the plasma membrane. We expressed the M-PMV structural genes (gag-pro-pol) in insect cells using a recombinant baculovirus. The polyprotein precursors assembled predominantly intracellularly, although a small proportion also assembled at the membrane. The protease enzyme was active since mature particles were identified in the culture supernatant. We also expressed the M-PMV mutants, D26N and gag-STOP, which carry a nonfunctional protease or fail to express the protease gene, respectively. These baculovirus recombinants generated a homogeneous population of immature M-PMV capsids having exclusively type D morphogenesis. Sufficient quantities of polyprotein precursors were synthesized to be visualized directly on a Coomassie-stained protein gel, and the capsids were subject to purification. These results provide the first expression of type D retrovirus particles using the baculovirus expression system.

Animals↗
PubMed1996

Antigenic properties and diagnostic potential of puumala virus nucleocapsid protein expressed in insect cells.

Puumala virus (PUU) is a member of the genus Hantavirus in the family Bunyaviridae and the causative agent of nephropathia epidemica, a European form of hemorrhagic fever with renal syndrome. Sera of nephropathia epidemica patients react specifically with PUU nucleocapsid (N) protein. In order to safely provide large quantities of antigen for diagnostic purposes, PUU Sotkamo strain N protein was expressed by using the baculovirus system in Sf9 insect cells to up to 30 to 50% of the total cellular protein. The recombinant N protein (bac-PUU-N) was solubilized with 6 M urea, dialyzed, and purified by anion-exchange liquid chromatography. In an immunoglobulin M mu-capture assay purified and unpurified bac-PUU-N antigen showed identical results compared with the results of a similar assay based on native PUU antigen grown in Vero E6 cells. An immunoglobulin G monoclonal antibody-capture assay based on unpurified bac-PUU-N also showed results identical to those of an assay with native PUU-N antigen. Moreover, a panel of monoclonal antibodies reactive with eight different epitopes showed identical reactivity patterns with both natural and bac-PUU-N antigen, while two epitopes in PUU-N expressed as a fusion protein in Escherichia coli were not recognized. Puumala hantavirus N protein expressed by the baculovirus system offers a safe and inexpensive source of specific antigen for large-scale diagnostic and seroepidemiological purposes.

Animals↗
PubMed1980

Chemically-defined media for production of insect cells and viruses in vitro.

Two chemically-defined media are described. They support the growth of a) an established cell line of Spodoptera frugiperda cells and b) two established mosquito cell lines from Aedes aegypti and Anopheles gambiae. The replication of Autographa californica Nuclear Polyhedrosis Virus (ACNPV) in S. frugiperda cells grown in a defined medium is reported.

Aedes↗
PubMed2001

Recombinant hemagglutinin protein of rinderpest virus expressed in insect cells induces humoral and cell mediated immune responses in cattle.

Rinderpest virus causes a highly contagious and often fatal disease in domestic and wild ruminants. The surface glycoproteins, hemagglutinin (H) and fusion (F) proteins of this enveloped virus are known to confer protective immunity in cattle. We have reported the generation of a recombinant baculovirus expressing H protein and studied its protective properties in cattle. In this report, we demonstrate that the recombinant baculovirus encoded H protein expressed in insect cells gets incorporated into extracellular baculovirus. Single administration of low doses of purified recombinant extracellular virus with or without adjuvant induces virus neutralizing antibody responses and bovine leukocyte antigen (BoLA) class II restricted helper T cell responses in cattle.

Animals↗
PubMed1991

Retarded processing of influenza virus hemagglutinin in insect cells.

When expressed in Spodoptera frugiperda cells by a baculovirus vector, the hemagglutinin of fowl plague virus has been found to contain palmitic acid in covalent hydroxylamine-sensitive linkage, indicating that these cells have the capacity to acylate foreign proteins at cysteine residues. Centrifugation on sucrose density gradients and immune precipitation with conformation-specific antibodies were used to compare trimerization of the hemagglutinin in insect cells and in fowl plague virus-infected MDCK cells. Trimerization of the hemagglutinin was incomplete in insect cells, and the kinetics of this reaction were about three times slower than in vertebrate cells. Similarly, post-translational proteolytic cleavage occurred in insect cells with a half-time of 90 min, and a substantial fraction of the hemagglutinin persisted in uncleaved form. In contrast, hemagglutinin was almost completely cleaved in MDCK cells, and the half-time of cleavage was only 30 min. The data indicate that in insect cells trimerization and, as a result, the subsequent processing steps of the hemagglutinin, are retarded and less efficient. The possible roles of aberrant glycosylation, acidic milieu, and lack of other influenza virus proteins in hemagglutinin trimerization are discussed.

Acylation↗
PubMed1993

Glycoprotein E1 of hog cholera virus expressed in insect cells protects swine from hog cholera.

The processing and protective capacity of E1, an envelope glycoprotein of hog cholera virus (HCV), were investigated after expression of different versions of the protein in insect cells by using a baculovirus vector. Recombinant virus BacE1[+] expressed E1, including its C-terminal transmembrane region (TMR), and generated a protein which was similar in size (51 to 54 kDa) to the size of E1 expressed in swine kidney cells infected with HCV. The protein was not secreted from the insect cells, and like wild-type E1, it remained sensitive to endo-beta-N-acetyl-D-glucosaminidase H (endo H). This indicates that E1 with a TMR accumulates in the endoplasmic reticulum or cis-Golgi region of the cell. In contrast, recombinant virus BacE1[-], which expressed E1 without a C-terminal TMR, generated a protein that was secreted from the cells. The fraction of this protein that was found to be cell associated had a slightly lower molecular mass (49 to 52 kDa) than wild-type E1 and remained endo H sensitive. The high-mannose units of the secreted protein were trimmed during transport through the exocytotic pathway to endo H-resistant glycans, resulting in a protein with a lower molecular mass (46 to 48 kDa). Secreted E1 accumulated in the medium to about 30 micrograms/10(6) cells. This amount was about 3-fold higher than that of cell-associated E1 in BacE1[-] and 10-fold higher than that of cell-associated E1 in BacE1[+]-infected Sf21 cells. Intramuscular vaccination of pigs with immunoaffinity-purified E1 in a double water-oil emulsion elicited high titers of neutralizing antibodies between 2 and 4 weeks after vaccination at the lowest dose tested (20 micrograms). The vaccinated pigs were completely protected against intranasal challenge with 100 50% lethal doses of HCV strain Brescia, indicating that E1 expressed in insect cells is an excellent candidate for development of a new, safe, and effective HCV subunit vaccine.

Animals↗