Structure-Activity Research Of Bursin-Like Peptides

Bursin was the first peptide extracted from bursal, which play an important role in the generation and maintenance of antibody, and could increase the humoral immune response and enhance cellular immunity in mass research. However, whose metabolism was not clear in the body, and clinical effects was not better enough.In ordor to explore the relationship between structure and immuno-enhancing activity of bursin-like peptides, single copy bursin (BS),30copies bursin in series (KG30) and30copies bursin in three branch (10copies per branch,MAP) were synthesised, and wer compared by test. The more activity peptide will be found and which was the foundation for further research and clinical application.1The effect of bursin-like peptides on lymphocyte proliferationTo research the immunity of different structure of bursin-like peptides, the lymphocyte proliferation rate of the three bursin-like peptides were testby MTT assay. Resulte showed that BS was the best, with the proliferation rate49.2%, and the next was MAP (P<0.05). Research showed that the single copy bursin can increase the lymphocyte proliferation rate significantly in the lymphocyte proliferation transformation trial in vitro.2The effect of bursin-like peptides on antibody-secreted by hybridomaThe hybridoma were incubated respectively with the three bursin-like peptides, and DMEM as control. The antibody-secreting of hybridoma were assayed by ELISA. The result showed that the best was MAP group with the antibody-secreting increased by14.83%, the next was BS (9.57%).3The effect of bursin-like peptides on T lymphocyte rosetteThe chiken blood lymphocytes were treated with the three bursin-like peptides, and physiological saline as control. Then he sheep red blood cells were added, and the Ea-rosette rate were calculated. The result showed that the Ea-rosette rate of BS and MAP group was better than KG30, those Ea-rosette rest were significantly increased by39.2%and29.2%conpared with the control group (P<0.05). This study proved that the bursin of BS and MAP can effectively increase rosette rest formation,and can improve the cellular immunity,and the best stimulation activity structure was BS. 4The effect of bursin-like peptides on PhagocytosisAfter inducing the macrophages to abdominal by starch, the mice were treated with the three bursin-like peptides, and physiological saline as control. Then1%chicken’s red blood to mice were injected. And then the peritoneal fluid were collected and stained with Giemsa. Finally, the Giemsa stained cells were counted. The result showed all the three bursin-like peptides can improve the phagocytic rate and phagocytic index of macrophages,took physiological saline ascontrol. BS was the best with the phagocytic index65.8%, and the next was MAP (57.72%, P<0.05).5The enhance effect of bursin-likes peptide on inactivated Newcastle vaccine100NDV-free chincken (1-day) were randomly divided into5groups, twenty per group.4groups were vaccinated with ND vaccine,and were intramuscularly injected with BS, KG30, MAP, respectively, and equal volum of physiological saline as control.10chickens were sampled randomly from each group for determining serum titer of HI antibody against the ND vaccine and IL-2, IL-4.The result showed all the three bursin-like peptides can significantly improve the bursal index and the level of antibody (P<0.05), the difference between MAP group and BS group was not significantly(P>0.05), and the MAP also can increase the secreting of IL-4significantly. The MAP was best of all.