16/19) of the ALV-J layer isolates displayed less than 92.5% sequence homology to those of the ALV-J broiler isolates, although the transcriptional regulatory elements that are typical of avian retroviruses were highly conserved. Several unique nucleotide substitutions in the env gene, the U3 region, and the E element of most of the ALV-J layer isolates were detected. These results suggested that the env gene, E element, and U3 region in the ALV-J layer isolates have evolved rapidly and were significantly different from those of the ALV-J broiler isolates. These findings will contribute to a better understanding of the pathogenic mechanism of layer tumor diseases induced by ALV-J.

Severe acute respiratory syndrome (SARS) is a recently discovered viral disease, characterized by fever, cough, acute fibrinous pneumonia and high infectivity. Specific pathogen-free (SPF) chickens were immunized with inactivated SARS coronavirus and their eggs were harvested at regular intervals. Yolk immunoglobulin (IgY) was extracted using the water dilution method, followed by further purification on a Sephadex G-75 column. SDS-polyacrylamide gel electrophoresis (SDS-PAGE), Western blot and neutralization test results showed that the IgY obtained was of a high purity and had a strong reactive activity with a neutralization titer of 1:640. Lyophilization and stability tests showed that lyophilized anti-SARS coronavirus IgY had promising physical properties, with no significant reduction in reactive activity and good thermal stability. All these data suggest that the anti-SARS coronavirus IgY could be a new useful biological product for specific antiviral therapy against SARS.

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