Open AccessComparative Study of Three Different ELISA to Measure the Antibodies Against Infectious Bronchitis Virus in Vaccinated and Unvaccinated Broilers
Author(s) -
Tereza Cristina Cardoso,
Carlos Oliveira,
Sel Da-Silva,
Heder Nunes Ferreira,
AA Pinto
Publication year - 2001
Publication title -
brazilian journal of poultry science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.323
H-Index - 25
eISSN - 1806-9061
pISSN - 1516-635X
DOI - 10.1590/s1516-635x2001000100010
Subject(s) - titer , serotype , virology , serology , antibody , heterologous , neutralization , biology , virus , immunology , biochemistry , gene
Broilers were spray-vaccinated (n=150) with H120 serotype at one-day-old, challenged after 28 days with M41 IBV serotype and after bled at day 28, 34 and 46 after challenged. The respective sera were tested by the indirect ELISA (I-ELISA), sandwich ELISA (S-ELISA), liquid phase blocking ELISA (LPB-ELISA) and the standard serum neutralization test (SNT). For this purpose, a total of 300 sera samples, 150 from non vaccinated and 150 from vaccinated broilers were titrated by all the serological methods and the correlation coefficients were determined. The correlation values (r) between LPB-ELISA x SNT, S-ELISA x SNT, I-ELISA x SNT found werer = 0.98, r = 0.79, and r = 0.74, respectively. Nevertheless, the r between LPB-ELISA x S-ELISA, LPB-ELISA x I-ELISA and S-ELISA x I-ELISA were r = 0.75, r = 0.69 and r = 0.79. In fact , the I-ELISA and the S-ELISA had almost the same correlation with S-ELISA and LPB-ELISA, in contrast with the I-ELISA and LPB-ELISA. It was concluded that LPB-ELISA showed better sensitivity than I-ELISA and S-ELISA, also after 46 days challenge with the heterologous serotype. However, these two last techniques demonstrated similar specificity when the titers were compared with those obtained in SNT, even though after the heterologous serotype challenge the SNT produced better results. This study demonstrated the close relationship between LPB-ELISA and SNT assays. No presente estudo, foram vacinados 150 frangos de corte de um dia de idade com sorotipo H120, e, após 28 dias desafiados à vacinação com o sorotipo M 41 do vírus da bronquite infecciosa das aves. Da mesma forma, foram obtidos 150 soros de aves não vacinadas para a análise. Os respectivos soros foram analisados 28, 34 e 46 dias após o desafio, examinados através das técnicas de ELISA indireto (ELISA-I), Sandwich ELISA (S-ELISA) e ELISA com bloqueio de fase líquida (ELISA-BFL) e comparados com a técnica padrão de soroneutralização (SN) para efeito de cálculo da especificidade e sensibilidade relativas, bem como os valores predictivos positivos e negativos. O cálculo do coeficiente de correlação também foi empregado para a análise de concordância. Assim, os valores da correlação encontrados foram r = 0.98 entre ELISA-BFL x SNT, r = 0.79 entre S-ELISA x SNT e r = 0.74 ELISA-I x SNT. No entanto, quando comparamos as técnicas de ELISA entre si, ELISA-BFL x S-ELISA, ELISA-BFL x ELISA-I e S-ELISA x ELISA-I os valores encontrados foram r = 0.75, r = 0.69 e r = 0.79. A técnica de ELISA-BFL demonstrou melhor sensibilidade relativa que as técnicas de S-ELISA e ELISA-I, mesmo 46 dias após o desafio com a estirpe heteróloga. Entretanto, apesar das técnicas de S-ELISA e ELISA-I apresentarem especificidade realtiva superiores, a melhor correlação observada foi entre as técnicas de ELISA-BFL e a SN