Local Pathological Reactions and Immune Response of Chickens to ISA-70 and Other Adjuvants Containing Newcastle Disease Virus Antigen

SUMMARY. Chickens were examined for gross and microscopic changes at the injection site for 16 weeks after an intramuscular injection of the following oil adjuvant emulsions containing inactivated Newcastle disease virus (NDV) antigen: ISA-70, Freund's incomplete adjuvant (FIA), Freund's complete adjuvant (FCA), and aluminum phosphate gel (APG). The reactions induced by ISA-70 emulsion were characterized by proliferation of macrophages, epithelioid cells, and fibroblasts around the small cysts in the muscle. Infiltration of lymphocytes and plasma cells also was present. These changes peaked 2 weeks postinjection and were milder than lesions due to the Freund's adjuvants. FCA induced the most severe granulomatous lesions with abscess formation. The reactions to APG were characterized by proliferation and accumulation of macrophages. The serological results revealed that the enhancing effect of ISA-70 on NDV antigen was the same as that of FIA.