Immune response of chickens inoculated with a recombinant avian leukosis virus.

Specific-pathogen-free embryos (18-day incubation) and hatched chicks were inoculated with a recombinant avian leukosis virus (ALV) produced by recombinant DNA techniques. Enzyme-linked immunosorbent assays were used to measure the production of viral-protein-specific antibody and the viral protein, p27, in the serum at 2, 5, 8, 14, and 20 weeks of age. Of the inoculated chickens surviving to 20 weeks, 64% produced viral-protein-specific antibodies and 42% transiently produced the viral protein, p27. Chickens inoculated as embryos did not differ significantly from those inoculated at hatch with respect to antibody and viral protein production. Antibody production peaked at 5 weeks postinoculation and declined over the remaining 15 weeks of the study. No evidence of chronic tolerant infection or mortality due to neoplastic disease was found.