ROLE OF THE HUMORAL IMMUNE-SYSTEM IN SALMONELLA-ENTERITIDIS PHAGE TYPE-4 INFECTION IN CHICKENS

The role of avian humoral immunity in the clearance of S. enteritidis was evaluated through bursectomy. After oral inoculation of bursectomi zed and sham-treated chickens with S. enteritidis, faecal excretion of S. enteritidis was examined. Organs were collected weekly until six w eeks postinoculation (pi) for bacteriological enumeration. Antibody is otypes in serum and bile were quantified by ELISA. Faecal excretion of S. enteritidis was significantly lower in controls from 13 days pi. N umbers of S. enteritidis in caeca from controls were significantly dec reased from three weeks pi. Numbers of S. enteritidis were significant ly decreased at two weeks pi in the spleen and the liver and at six we eks pi in the liver. Antibodies to S. enteritidis peaked at two weeks pi in controls and were absent in bursectomized chickens. These findin gs indicate that elimination of S. enteritidis partly depends on humor al immunity. The intestinal humoral response appeared more effective t han the systemic humoral response for elimination of S. enteritidis. ( C) 1998 Elsevier Science B.V. All rights reserved.