Ref.CDVB014
96 tests/kit
PARAINFLUENZA 3
Bovine
General Information
PI 3 was first isolated in the USA from the nasal mucus or cattle
showing clinical signs of shipping fever. Its distribution in the cattle
has bee found to be worldwide. Most reports of Bovine PI 3 virus activity
have been in groups of young cattle with respiratory diseases such as
enzootic calf pneumonia and shipping fever. Bovine PI 3 virus infections
are not invariably associated with disease and subclinical infections
often occur. In European countries, PI 3 infection mostly occurs during
the months from October to March. PI 3 virus infection may be accompanied
by concurrent infection of the respiratory tract by other viruses such as
respiratory syncytial virus, adenovirus or BVDV. In outbreaks of Bovine
respiratory disease, it is not possible to diagnose PI 3 virus infection
on clinical grounds alone.
To establish a diagnosis, it is necessary to take paired sera from infected animals or to submit animals from the outbreak for necropsy to facilitate immunocytochemical examinations of the lower respiratory tract. PI 3 virus infection in an outbreak of respiratory disease can be detected by the demonstration of a rise in serum antibody titer to the virus between acute and convalescent phase serum samples (seroconversion).
Principle of the test
The Cypress Parainfluenza 3 test uses 96-well microtitration plates sensitized by monoclonal antibodies specific to one of the antigenic determinants of PI 3 virus. This antibody is used to trap the virus as well as to purify it from lysate of the cells in which the virus was grown.
The plates’ odd columns (1,3,...11) contain the virus, whereas the even columns (2,4,.....12) contain a lysate of GBK cell line that was used as a substrate to propagate the virus. We thus have a genuine negative control to differentiate the specific anti-viral antibody from the antibodies directed against the antigenic determinants of the testis cells used for its replication. Using such a control reduces the number of false positives considerably.
The test blood sera are diluted 1 : 100 in the buffer for dilution. The plate is incubated and washed, then the conjugate - a peroxidase labeled anti-Bovine IgG1 monoclonal antibody - is added to the wells. The plate is then incubated a second time at room temperature and washed again and the enzyme’s substrate (hydrogen peroxide) and the chromogen tetramethylbenzidine (TMB) are added. This chromogen has the advantages of being more sensitive than the other peroxidase chromogens and not being carcinogenic.
If specific PI 3 immunoglobulins are present in the test sera the conjugate remains bound to the microwell that contains the viral antigen and the enzyme catalyses the transformation of the colorless chromogen into a pigmented compound. The intensity of the resulting blue color is proportionate to the titer of specific antibody in the sample. The signal read off the negative control microwell is subtracted from that of the positive microwell sensitized by the viral antigen.
Comparison of the signals obtained for the unknown samples with those obtained for a reference serum, supplied with the kit, make it possible to rank the serums positivity on a five point scale.
Rev.09.95
