Sendai virus
Encyclopedia
Sendai virus also known as murine parainfluenza virus type 1 or hemagglutinating virus of Japan (HVJ), is a negative sense, single-stranded RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

 virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...

 of the Paramyxoviridae family, a group of viruses featuring, notably, the Morbillivirus
Morbillivirus
Morbillivirus is a genus belonging to the Paramyxoviridae family of viruses in the order Mononegavirales. Many members of the genus cause diseases, such as rinderpest and measles, and are highly infectious.- External links :* *...

and Rubulavirus
Rubulavirus
Rubulavirus is a genus of the Paramyxoviridae family of infectious viruses. The genus includes the mumps virus and parainfluenza type 2, 4a and 4b viruses.-External links:* http://www.biology-online.org/dictionary/Rubulavirus*...

genera. SeV is a member of the paramyxovirus subfamily Paramyxovirinae, genus Respirovirus, members of which primarily infect mammals.

SeV is responsible for a highly transmissible respiratory tract infection in mice, hamsters, guinea pigs, rats, and occasionally pigs, with infection passing through both air and direct contact routes. The virus can be detected in mouse colonies worldwide, generally in suckling to young adult mice. Epizootic
Epizootic
In epizoology, an epizootic is a disease that appears as new cases in a given animal population, during a given period, at a rate that substantially exceeds what is "expected" based on recent experience . Epidemic is the analogous term applied to human populations...

 infections of mice are usually associated with a high mortality rate, while enzootic
Enzootic
Enzootic is the non-human equivalent of endemic and means, in a broad sense, "belonging to" or "native to", "characteristic of", or "prevalent in" a particular geography, race, field, area, or environment; native to an area or scope....

 disease patterns suggest that the virus is latent and can be cleared over the course of a year. Sublethal exposure to SeV can promote long-lasting immunity to further lethal doses of SeV.

A novel and well-recognized use for SeV is the fusion of eukaryotic cells, especially to produce hybridoma
Hybridoma
Hybridoma technology is a technology of forming hybrid cell lines by fusing a specific antibody-producing B cell with a myeloma cell that is selected for its ability to grow in tissue culture and for an absence of antibody chain synthesis...

 cells capable of manufacturing monoclonal antibodies
Monoclonal antibodies
Monoclonal antibodies are monospecific antibodies that are the same because they are made by identical immune cells that are all clones of a unique parent cell....

 in large quantities.

Diagnosis and Prophylaxis

SeV induces lesions within the respiratory tract, usually associated with bacterial inflammation of the trachea and lung (tracheitis
Tracheitis
Tracheitis is an inflammation of the trachea.Although the trachea is usually considered part of the lower respiratory tract, in ICD-10 tracheitis is classified under "Acute upper respiratory infections".-Bacterial tracheitis:...

 and bronchopneumonia
Bronchopneumonia
Bronchopneumonia or bronchial pneumonia or "Bronchogenic pneumonia" is the acute inflammation of the walls of the bronchioles...

, respectively). However, the lesions are limited, and aren't indicative solely of SeV infection. Detection, therefore, makes use of SeV-specific antigens in several serological
Serology
Serology is the scientific study of blood serum and other bodily fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum...

 methods, including ELISA
ELISA
Enzyme-linked immunosorbent assay , is a popular format of a "wet-lab" type analytic biochemistry assay that uses one sub-type of heterogeneous, solid-phase enzyme immunoassay to detect the presence of a substance in a liquid sample."Wet lab" analytic biochemistry assays involves detection of an...

, immunofluorescence
Immunofluorescence
Immunofluorescence is a technique used for light microscopy with a fluorescence microscope and is used primarily on biological samples. This technique uses the specificity of antibodies to their antigen to target fluorescent dyes to specific biomolecule targets within a cell, and therefore allows...

, and hemagglutination assays, with particular emphasis on use of the ELISA for its high sensitivity (unlike the hemagglutination
Hemagglutination
Hemagglutination, or haemagglutination, is a specific form of agglutination that involves red blood cells . It has two common uses in the laboratory: blood typing and the quantification of virus dilutions.-Blood Typing:...

 assay) and its fairly early detection (unlike the immunofluorescence assay).

Eaton et al. advises that, when controlling an outbreak of SeV, disinfecting the laboratory environment and vaccinating the breeders, as well as eliminating infected animals and screening incoming animals, should clear the problem very quickly. Imported animals should be vaccinated with SeV and placed in quarantine, while, in the laboratory environment, breeding programs should be discontinued, and the non-breeding adults isolated for two months .

Symptoms

  • Sneezing
  • Hunched posture
  • Respiratory distress
  • Porphyrin
    Porphyrin
    Porphyrins are a group of organic compounds, many naturally occurring. One of the best-known porphyrins is heme, the pigment in red blood cells; heme is a cofactor of the protein hemoglobin. Porphyrins are heterocyclic macrocycles composed of four modified pyrrole subunits interconnected at...

     discharge from eyes and/or nose
  • Lethargy
  • Failure to thrive in surviving babies and young rats
  • Anorexia

Sendai Fusion

One recognized feature of the Sendai virus, shared with members of its genus, is the ability to induce syncytia formation in vitro in eukaryotic colonies. The mechanism for this process is fairly well understood and is very similar to the fusion process employed by the virion to facilitate cellular entry. The activities of the receptor binding hemagglutinin
Hemagglutinin
Influenza hemagglutinin or haemagglutinin is a type of hemagglutinin found on the surface of the influenza viruses. It is an antigenic glycoprotein. It is responsible for binding the virus to the cell that is being infected...

-neuraminidase
Neuraminidase
Neuraminidase enzymes are glycoside hydrolase enzymes that cleave the glycosidic linkages of neuraminic acids. Neuraminidase enzymes are a large family, found in a range of organisms. The most commonly known neuraminidase is the viral neuraminidase, a drug target for the prevention of the spread...

 protein is solely responsible for inducing close interaction between the virus envelope and the cellular membrane. However, it is the F protein (one of many membrane fusion proteins) that, when triggered by local dehydration and a conformation change in the bound HN protein, actively inserts into the cellular membrane, which causes the envelope and the membrane to merge, followed shortly by virion entry. When the HN and F protein are manufactured by the cell and expressed on the surface, the same process may occur between adjacent cells, causing extensive membrane fusion and resulting in the formation of a syncytium.

This behavior of SeV was utilized by Köhler and Milstein, who published an article in 1975 outlining a revolutionary method of manufacturing monoclonal antibodies
Monoclonal antibodies
Monoclonal antibodies are monospecific antibodies that are the same because they are made by identical immune cells that are all clones of a unique parent cell....

. In need of a reliable method to produce large quantities of a specific antibody, the two merged a monoclonal B cell
B cell
B cells are lymphocytes that play a large role in the humoral immune response . The principal functions of B cells are to make antibodies against antigens, perform the role of antigen-presenting cells and eventually develop into memory B cells after activation by antigen interaction...

, exposed to a chosen antigen, and a myeloma tumor cell to produce hybridoma
Hybridoma
Hybridoma technology is a technology of forming hybrid cell lines by fusing a specific antibody-producing B cell with a myeloma cell that is selected for its ability to grow in tissue culture and for an absence of antibody chain synthesis...

s, capable of being grown indefinitely and of producing significant amounts of an antibody specifically targeting the chosen antigen. Though more efficient methods of creating such hybrids have since been found, Köhler and Milstein first used Sendai virus to create their revolutionary cells .

External links

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