Aujeszky's disease in the guinea pig: cellular and humoral responses following immunization.

The fatal disease caused by virulent ADV in guinea pigs was found to be identical to that seen in sheep and cattle. Intramuscular (i.m.) injection of an avirulent strain of ADV (Bartha) yielded better immunity to challenge after 3 weeks than did intranasal (i.n.) immunization, and this was reflected in differences in histopathological changes in the brain. Serum antibodies active in antibody-dependent cell-mediated cytotoxicity (ADCC) were titrated using polymorphonuclear leukocytes as effector cells. ADCC correlated fairly well with virus neutralization and was a far more sensitive technique. There was good, but not complete, correlation between ADCC and protection. Lymphocyte responsiveness to virus antigens in vitro was assessed by 3H-thymidine uptake and lympholine tests. Lymphocyte stimulation and mitogenic factor responses were low grade but blood lymphocyte stimulation was more pronounced in the better-protected animals. Macrophage migration inhibition correlated neither with serum ADCC nor with protection, being equally demonstrable in the two immunized groups.