The application of ELISA to serology virus typing in new cattle disease

anglais. Newcastle disease is the major viral disease of poultry, causing serious economic loss in most countries (except Australia and New Zealand). Serology is carried out using the haemagglutination-inhibition (HI) test and pathotyping is carried out by assay in chick embryos (mean death time), 1 day old chicks (intracerebral pathogenicity index) or 6-8 week old chickens (intravenous pathogenicity index). New serological assays involving ELISA technology were developed for the assay of antibody levels in chickens. An indirect ELISA was performed using purified Newscastle disease virus (NDV), coated directly onto inexpensive polystyrene plastes, followed by detection of bound antibody using a sheep anti-chicken-HRPO labelled conjugate. A standard curve was included on every plate, enabling conversion into ELISA units, which bore a direct relationship to HI titres. Monoclonal antibodies (MAbs) were used in blocking/competition assays to measure the levels of antibodies to the HN and NP proteins in chickens. MAbs were also used in typing NDV isolates. The binding patterns of a panel of MAbs were used to separate isolates into epidemiological groups, but these groups do not necessarily reflect the virulence of the isolates. Group creative MAbs were used to stain the chorioallantoic membrane (CAM) in NDV infected chick embryos. Only the endodermal cell layer stained for avirulent and low virulence isolates, whereas all cell layers stained for medium and high virulence isolates. Further studies are under way that might lead to simple ELISAs for pathotyping NDV isolates

inconnu. Tetelo (Newcastle disease) adalah penyakit virus yang utama pada unggas, yang dapat menyebabkan kerugian ekonomi yang tidak sedikit di banyak negara (kecuali Australia dan Selandia Baru). Uji hemaglutinasi inhibisi (HI) digunakan untuk uji serologi, dan tipe patogenitas virus dilakukan dengan uji pada embrio ayam (rata-rata kematian ayam), anak ayam umur 1 hari (indeks patogenitas secara intra serebral) atau ayam berumur 6-8 minggu secara intravena indeks patogenitas. Metoda serologi yang baru melibatkan teknologi ELISA yang dikembangkan untuk menguji titer antibodi pada ayam. Uji ELISA tidak langsung dengan menggunakan virus Newscastle disease (NDV) yang dimurnikan, langsung melapisi mikrotiter plat polistirene yang tidak mahal, dilanjutkan dengan penentuan antibodi yang telah diikat dengan konjugat domba anti ayam yang telah dilabel HRPO. Sebuah kurva standar dikutsertakan setiap plat untuk mengkonversikan titer antibodi menjadi ELISA unit, yang merupakan hubungan langsung dengan titer HI. Antibodi monoklanal (MAb) digunakan pada uji hambatan (bloking) untuk mengukur tingkat antibodi pada protein HN dan NP pada ayam