SEROLOGICAL ASSAYS FOR THE IDENTIFICATION OF OESOPHAGOSTOMUM-DENTATUMINFECTIONS IN PIGS

Oesophagostomum dentatum antigen preparations of third (L-3) Or fourth (L-4) stage larvae were characterised by Western blotting. Panels of sera obtained from pigs infected with O dentatum and Ascaris suum, res pectively, reacted with the same bands of L-3 antigen. In contrast hig h specificity against a characteristic band, was observed when L-4 ext ract was employed as antigen. To establish an enzyme-linked immunosorb ent assay (ELISA), a panel of homologous and heterologous sera was tes ted against O dentatum L-4 extract. The best combined specificity and sensitivity was obtained when horseradish peroxidase (HRP) goat anti s wine IgG conjugate was used rather than HRP rabbit anti swine Ig conju gate. Testing series of sera from pigs infected with single doses of e ither 2000, 20,000 or 200,000 infective larvae by the ELISA, a signifi cant dose dependency in the antibody response was observed between the low and high dosage groups. This assay may be useful in future studie s of the immune-mechanisms against nodular worm infections in pigs.