Identification of Sendai virus mRNA species.

Cell-free translation of separated Sendai virus mRNA species identified the message for polypeptide M and suggested the identity of the message for polypeptide NP.     

Isolation and characterization of Sendai virus DI-RNAs.

When passaged at high multiplicity, four strains of Sendai virus all showed evidence that they contained defective interfering (DI) particles. RNA isolated from nucleocapsids of cells infected with the high multiplicity passage stocks was found to consist of only minor amounts of nondefective genome length RNA and major amounts of smaller RNAs, the DI-RNAs. These DI-RNAs were found to have unusual and variable sedimentation properties in sucrose gradients, but were found to represent unique segments of the viral genome by length measurements in the electron microscope and by hybridization. A striking feature of the DI-RNAs is their ability to form circular structures, indicating that the ends of the DI-RNA are complementary. The implications of this finding in terms of the mechanism of genome replication is discussed.     

Gene delivery systems using the Sendai virus.

Fusogenic liposome (FL) is a delivery system that can transfer encapsulated materials into living cells directly through membrane fusion. FL is a promising approach for gene therapy because it can deliver various genetic materials much more efficiently than other non-viral vectors without damaging the cell. FL-mediated gene transfer consists of two independent membrane fusion phenomena; generation of a FL by fusing a Sendai virus (SV) particle with a simple liposome encapsulating DNA, and successive fusion of the FL with cell membrane. The former requires viral F protein but no other special molecule on the liposomal membrane, whereas the latter may require the receptor (sialic acid) and unidentified assistant molecule(s) on the cell membrane. Further analysis suggests that these assistant molecule(s), not the receptor, may control the fusion and govern the cell specificity of FL-mediated delivery. This review has described a detailed analysis of these fusion phenomena and discussed possible applications of FL-mediated gene delivery to human gene therapy.     

Sendai virus stimulates chemiluminescence in mouse spleen cells.

Sendai virus stimulates chemiluminescence within a few seconds after it is added to a suspension of mouse spleen cells. Virus rendered non infectious by irradiation with ultraviolet light induces a similar burst of chemiluminescence. Heating or pronase treatment of the virus abrogate this reaction, as does sonication of the cells before the addition of the virus. The ability of the virus to stimulate chemiluminescence is correlated with its hemagglutination, neuraminidase, cell fusion and hemolytic properties. It is suggested that Sendai virus-induced chemiluminescence is initiated by the interaction of the virus envelope spike glycoproteins with the cell membrane.     

Sendai virus infection of mice with protein malnutrition.

Sendai virus pneumonia was produced in BALB/c mice fed protein-deficient diets in an effort to understand the severity of viral pneumonia in infants in developing countries. Animals on the deficient diet became clinically malnourished, and some aspects of cellular immunity were altered. In protein-deprived animals, the 50% lethal dose of intranasally administered Sendai virus was over 1,000-fold lower, pulmonary virus titers were higher, the infection was prolonged, and lung infection was established at a lower inoculum than in normal animals.     

Cytotoxic T-lymphocyte reactivity with individual Sendai virus glycoproteins.

Liposomes were constituted with affinity-purified Sendai virus glycoproteins HN and F and phosphatidylcholine (PC) or phosphatidylethanolamine: phosphatidylserine (PEPS). The glycoprotein-bearing recombinant vesicles (RV) were used to modify the surface of P815 mastocytoma cells (H-2d) or EL4 lymphoma cells (H-2b). The cells treated with HN-F-PCRV, HN-PEPSRV, or F-PEPSRV were shown by surface immunofluorescence to retain antigen for at least 2 h at 37 degrees C after treatment. The modified cells were used in cytotoxicity assays with effector spleen cells from either DBA/2 (H-2d) or C57BL/6 (H-2b) immunized by inoculation of active Sendai virus. Cells modified by treatment with HN/F-PCRV showed susceptibility to cytolysis similar to that in actively infected cells. Cells modified with HN-PEPSRV or with F-PEPSRV were also susceptible. The sum of reactivities of the anti-HN component and the anti-F components was close to that seen with HN- and F-bearing targets. Syngeneic but not allogeneic target cells expressing Sendai virus glycoproteins were bound and lysed by the effector cells, which was expected if the interactions were major histocompatibility complex restricted. The activity was attributed to cytotoxic T lymphocytes, since it was depleted by treatment with anti-Thy 1.2 antibody and complement.     

Immunoglobulin A monoclonal antibodies protect against Sendai virus.

Immunoglobulin A anti-Sendai virus HN protein monoclonal antibodies, generated via a mucosal immunization protocol, were shown to neutralize virus in vitro and, when passively administered to the mouse respiratory tract, to protect against Sendai virus in vivo. Thus, immunoglobulin A antibodies by themselves can protect against respiratory virus infection.     

Inhibition of Sendai virus by various snake venom.

Viperid, elapid and crotalid snake venoms were screened in vitro for antiviral activity against Sendai virus. The hemolysis of 10(8) human erythrocytes in 1 ml, caused by 70 HAU of Sendai virus, was abolished when the virions were pretreated with 10 ug of the viperid venom of Echis coloratus, and was considerably diminished when pretreated with 10 ug of the venom of Echis carinatus sochureki, the cobra venoms of Naja atra and Naja nigricollis nigricollis. These venoms did not affect the erythrocytes but inhibited the virions themselves irreversibly. All other examined snake venoms had low or no antiviral activity. There was no correlation between the proteolytic and the antiviral activity of the venoms.     

High-titer replication of nondefective Sendai virus in MDBK cells.

Egg-grown Sendai virus was adapted to growth in a bovine kidney cell line (MDBK cells) by serial passage under defined conditions. The adapted virus contained only 50S RNA and was highly infectious for MDBK cells. Infection of these cells with a high multiplicity of adapted virus resulted in a yield of 10(8) MDBK-infectious units/ml by 18 h, accompanied by severe cytopathic changes in the host. Cell fusion did not occur. Examination of the proteins of the adapted virus revealed that despite the high infectivity of this virus for MDBK cells the virions contained considerable quantities of Fo, the precursor to the F glycoprotein that is responsible for cell fusion and high infectivity in other systems.     

Effect of poliovirus superinfection on Sendai virus protein synthesis.

Poliovirus superinfection of Sendai virus-infected cells inhibited the syntheses of the structural P protein and the nonstructural C' and C proteins equally. As the Sendai virus P, C', and C proteins are all translated from the same mRNA by ribosomes which initiate on alternate AUGs and as non-poliovirus protein synthesis is inhibited in poliovirus-infected cells by inactivation of initiation factors responsible for cap group recognition, these results indicate that cap group recognition is important for ribosome initiation on AUGs which are not proximal to the 5' end of the mRNA.     

Infection of rabbits with Sendai virus

Rabbits were either inoculated with Sendai virus (SV), strain MN, or caged with virus-inoculated rabbits on the same day of the viral inoculation, and examined for viral shedding and detection of viral antigens in the respiratory tract, histopathologic changes, and serum antibodies. Infectious virus was recovered from nasal swabs at postinoculation day (PID) 3 and disappeared by PID 10. Viral antigens were detected by immunofluorescence in epithelial cells of the nasal cavities, but not of the trachea and lungs from PID 3 to PID 10, and antibodies were detected after PID 7. Rabbits had no clinical manifestations and only exhibited a moderate increase in goblet cells of the nasal epithelium. In the transmission study, virus was recovered from one of three uninoculated rabbits at postexposure day (PED) 10 and antibodies were detected at PED 15 in the same rabbit. These data suggest that, although viral multiplication was limited to the nasal epithelium, laboratory rabbits are susceptible to Sendai virus infection.     

Stimulation and modulation of adenylate cyclase by Sendai virus.

Stimulation of adenylate cyclase activity occurs in membranes prepared from toad erythrocytes preincubated briefly (at 37° or 4°) with ultraviolet light-inactivated Sendai virus. Stimulation occurs with as few as five virions per cell, and it is blocked by pretreating the virus with the membrane glycolipid, ganglioside GM₁. Virus treatment also alters modulation of adenylate cyclase by hormones, nucleotides and sodium fluoride. Interactions of viral envelope antigens with plasma membrane components may thus elicit functional changes possibly important in the pathogenesis of viral infections.