Effects of BF-Sensitization on Immune Responses at Different Stages of Development in Chicks
1999 Volume 36 Issue 6 Pages 354-363
Details
1999 Volume 36 Issue 6 Pages 354-363
Effects of administration of two antigens, sheep red blood cell (SRBC) and Brucell abortus (BA), via the bursa of Fabricius (BF-sensitization with antigens) on immune responses were studied in growing chicks. The effects of BF-sensitization with a bacterial antigen (BA) on IgA-producing cell count in the lamina propria of the jejunum were also examined. Antibody titers were significantly increased by BF-sensitization from 1 weeks of age to 11 weeks of age. Maximal augmentations of anti-SRBC and -BA antibody productions were observed in chicks BF-sensitized at 6 to 8 weeks of age. Responses after 4 and 7 days of intravenous booster injection of SRBC in chicks received the BF-sensitization at 1 and 6 weeks of age were higher than those of control chicks which received the i.v. administration alone. The responses were also higher than the control in chicks received the BF-administration of BA at 1, 6 and 11 weeks. Augmentation of antibody productions after the i.v. booster injection were maximal in chicks received the administration via the BF at 6 weeks of age, except for the response at 4 days after the i.v. injection of BA. Number of anti-SRBC-antibody-producing cells were increased by BF-sensitization from 1 week of age to 15 weeks of age, with maximal augmentation in chicks sensitized at 6 weeks of age. The counts after booster i.v. injection were also increased in chicks BF-sensitized from 1 week of age to 15 weeks of age. The counts received the i.v. booster injection were also maximal in chicks BF-sensitized at 6 weeks of age. Numbers of IgA-producing cells in the lamina propria of the jejunum were significantly increased by BF-sensitization with BA at 9 weeks of age as compared with those of age-matched untreated chicks. These results suggested that follicle-associated epithelium (FAE) of the BF contributed to establishment of the intestinal defence mechanism by IgA-producing lymphocytes as estimated in M cells of ruminants.
