Comparison of IFA and ELISA in the Detection of Avain Leukosis Virus Subgroup J in DF-1 Cell Cultures

To evaluate three kinds of ELISA avain leukosis virus (ALV) p27 antigen kits A, B, C, an infectious clone rNX0101 of ALV subgroup J were inoculated into DF1 cells with three different doses (9×103, 9×102, 90TCID50 separately) and the supernatant of DF1 cell cultures were obtained at 1-6 days post inoculation and tested with three kinds of kits after freezing and thawing once. The infected cell was detected by ALV-J specific monoclonal antibody JE9 at 3 and 6 days post inoculation separately also. Results indicated the infected cells at 3 days and 6 days post inoculation all can be identified by IFA after inoculated with different dose, while only the kit A can detect the p27 antigen at 3 days post inoculation with the high dose and none of inoculated cells was detected positively if with B and C ELISA kits at the same time. All samples infected by different doses showed positive to ALV-J whether by three ELISA kits or by IFA 6 days post inoculation. The result indicated the sensitivity between A, B and C ELISA kits in the detection of ALV-J with three doses of inoculation and the IFA is more sensitive than commercial ELISA kit.