The Relative Levels of Neutralizing and Precipitating Antibodies Against Infectious Bursal Disease Virus and Their Correlation with Resistance to a Highly Virulent Challenge Strain
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چکیده
Maternai antibodies, even at relatively high levels protecting against mortality and gross bursal les ions, appeared to be inadequate in preventing infection with a highly virulent infectious bursal disease virus (IBDV) strain. A comparison between the sensitivity of a cell culture microtitre virus neutra/ization (VN) technique and a quantitative agar gel precipitation (QAGP) test, used to measure the relative antibody levels to IBD V, showed that the former technique was significantly more sensitive than the latter. False negative results, ranging from 2% to 100% (depending on VN antibody titres ), were found in the QAGP tests, while false positive reactions were not observed . Evaluation of two IBD /ive vaccines, one relating to so-called " intermediate " and the other to " hot" strains, indicated that these lacked sufficient invasiveness in breaking through moderately high antibody titres. Study of the susceptibility of maternally immune birds to a challenge revealed that, within the scope of this investigation, the rate of bursal infection, at a given VN antibody titre, did not differ markedly in the two genetic fines of light and heavy breeds of chickens. The speculative significance of this finding , in relation to the differences existing between susceptibility of the layer and broiler type chicks to the disease, has been discussed.
منابع مشابه
The Relative Levels of Neutralizing and Precipitating Antibodies Against Infectious Bursal Disease Virus and Their Correlation with Resistance to a Highly Virulent Challenge Strain
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تاریخ انتشار 2017