Dictyocaulus viviparus in calves: quantitation of antibody activities in sera and respiratory secretions by immuno-enzymatic analysis.

An enzyme-linked immunosorbent assay (Elisa) which is in detail described here has been adapted to trace antibody production in different fluids from infected calves. Seven calves were infected both with Dictyocaulus viviparus, and with several intestinal nematodes. Antibodies against an antigen prepared from Dictyocaulus viviparus adult worms were first detected during the 5th week post-infection, both in serum and nasal secretions, and were also observed in bronchial washings of the same calves slaughtered 53 days post-infection. IgA antibodies were never evident in the serum but were found in limited quantities in nasal secretions. In bronchial washings at slaughtering, a significant part of antibody activity is accounted for by the local IgA production.