Figure 1.

Isolation and identification of ALV-J local chicken isolates. (A) The supernatants of DF-1 cells were assessed using ALV p27 antigen ELISA (42). Following OD₆₅₀ measurement, the S/P ratios were calculated and used to express the S/P ratio per sample. S/P values greater than or equal to 0.2 were considered positive. The red line indicates the cut-off value for ELISA. (B) Identification of 18 isolates by subgroup A-, B-, and J-specific multiplex PCRs. DF-1 cells infected with Rous-associated virus type 1 (subgroup A), Rous-associated virus type 2 (subgroup B), and HPRS-103 (subgroup J) were used as the positive control for PCR with primer pairs PF/AR, PF/BR, and PF/JR, respectively. Uninfected DF-1 cells served as the negative control. Abbreviation: ALV-J, Avian leukosis virus subgroup J.