| Lymphocytes of birds consist of two major lineages: T or thymus derived cells and B or bursal cells. A tripeptide hormone bursin ( Lys-His-Gly-NH2 ) which occurs in the bursa of Fabricius possesses many bioactivities such as stimulates the production of antibody, promotes the normal growth of the bursa of Fabricius and resists immunodepressive factors, and these bioactivities mainly depend on finishing in vivo. In order to further studying the biological roles of bursin, sensitive methods of quantitative and qualitative measurement will be useful. An indirect inhibition enzyme-linked immunoadsorbent assay (ELISA) and an ultraviolet spectroscopy assay were described for immunoactive tripeptide bursin. First, synthesis bursin as standard sample could inhibit the reaction between antibody against bursin conjugated to bovine serum albumin (BSA) and bursin conjugated to human serum albumin (HSA), the standard curve and regression equation was obtained and used in measurement of bursin. Second, the light adsorption values of bursin with different concentrations at different wavelengths were observed by using ultraviolet spectropolarimeter. At the wavelength of 230nm, the regression equation was obtained between bursin concentrations and light absorption values. Comparison of the two methods indicated that indirect inhibition ELISA was more sensitive and more specific, while ultraviolet spectroscopy was simpler and more rapid. A model for assay of bursin biological activity in vitro was established according that proper concentration of bursin could promote hybridoma cells secreting monoclonal antibody. The model was simple and stable. Bursin of high concentration could induce hybridoma cells and calf testis cells apoptosis, while it had no effect on CEF. This bioactivity Q5 bursin inducing apoptosis had not been reported. This discoveiy will. have important significance on apoptosis induced by small molecule bioactive peptide. |
