Plant & Animal Genome VI Conference

P52

DISTRIBUTION OF LYMPHOCYTE ANTIGENS, ANTIBODY PRODUCTION AND PHAGOCYTIC ACTIVITY IN CHICKEN LINES DIVERGENTLY SELECTED FOR SERUM IMMUNOGLOBULIN M AND G LEVELS

Laboratory of Animal Breeding and Genetics, Faculty of Applied Biological Science, Hiroshima University, Higashi-Hiroshima 739, Japan

The purpose of the present study were to investigate the effect of divergent selection for serum immunoglobulin isotypes on the changes in lymphocyte populations and immmune response to chickens. Peripheral blood lymphocyte antigens were measured by flow cytometry at 17, 18, and 19 weeks of age. At 20 weeks of age 20 birds from all the lines were intravenously immunized with one ml of Brucella abortus (BA) antigen. In vivo phagocytosis was measured by carbon clearence assay at 25 and 30 weeks of age. The relative amount of carbon remain in the sample at 3 and 15 minutes after carbon injection was measured by spectrophotometer. Flow cytometry revealed generally more circulating B cells in the HIM and HIG lines than their low counterparts. CD4+ cells were significantly (P<0.05) higher in the LIM line than HIM and LIG lines at 19 weeks of age. On the contrary, CD8+ cells were comparatively higher in the LIM and LIG lines. Total and 2-mercaptoethanol resistant antibody titers to BA were significantly (P<0.01) higher in the HIM line than the LIG line at 7 and 14 day postimmunization. The phagocytic ability of carbon was significantly (P<0.01) higher in the HIM line than all other lines. From the result it is suggested that divergent selection of chickens for immunoglobulin isotypes has altered the immunocompetent cells and the catabolic activity of macrophages has greatly been affected resulting immune differences in the selected lines.