Research On The Regulations Of Humoral Immunity In Chicken Inclusion Body Hepatitis

In order to reveal the humorol immunity changes in avian inclusion body hepatitis (IBH), foul adenovirus type 8 (FAV-8) was diluted to 1:50(W/V). 100 one-day-old SPF chickens were innoculated at a dose of 0.3 mL per chicken. And 10 of experimental group and 10 of control group were killed at 1,3,5,7,9,12,15,20,25 and 30 days post inoculation (dpi) respectively. All the lymphocyte suspension of peripheral blood, thymus, Fabricius bursa and spleen were collected, then the changes of B lymphocyte were detected by FCM and IgG, IgM antibody were also detected by ELISA, dispersion nephelometry and virus neutralization. Then the liver and lymph tissue were collected to prepare paraffine embedded sections and stained with HE to reveal the pathological changes. The results show that:(1) The Bu-1a+ B lymphocytes in Fabricius were very significantly higher than control group (p<0.01)at 1, 3dpi, it is significantly lower than control group at 15dpi(p>0.05). The Bu-1a+ B lymphocytes in spleen have no significant difference with that of the control group (p>0.05). The Bu-1a+ B lymphocytes in blood were very significantly lower than the control group (p<0.01) it was significantly lower than the control group at 3, 20dpi(p<0.05) and were significantly higher than the control group at 12dpi(p<0.05). (2) The content of IgG in peripheral blood showed an slowly descending trend from 1 to 7dpi, it rised a little at 9dpi, after 9dpi it descended a bit but maintained on a stable level. The IgG content was very significantly lower than at 1, 20dpi(p<0.01), it was significantly lower than the control group at 7,15, 25dpi(p<0.05) but it was higher than control group at 12, 30dpi(p<0.05). It was consistant with the changes of Bu-1a~+B lymphocytes. (3) The content of IgM in peripheral blood were higher than 0.88mg/mL 1 to 3 dpi. Then it decreased dramatically to a very low level (lower than 0.10mg/ml) and last to the end. The others were little higher than control group but had little significance. (4) The content of neutralizing antibody appeared at 3 dpi, it rised slowly from 1 to 9dpi but the content maintained on a low level. From the 9dpi it rised significantly and got up to a peak in 20th day. The content of neutralizing antibody maintained on a high level from 15 to 25dpi and descended a little at 30dpi. (5) The IBH virus infected organs showed different extent of hemorrhage. Large amount of B lymphocyte ran off and injured, especially in the Fabricius bursal. The result above showed that when the Bu-1a+B cells in blood were attacked by virus, they were damaged seriously in one hand, in another hand the B lymphocytes transformed into plasmocyte which produced IgM and IgG, thus its content decreasd significantly. Meanwhile the...