Amplifying,Cloning,Sequencing And Analysis Of Canine Interleukin-21

Interleukin (IL) , at first, means that it was secreted by the leukocyte and played the role between leukocytes as a kind of cytokine, but afterwards it was reported and discovered that Interleukin not only can also be produced by other cells , but also can have an effect on other cells. Now Interleukin refers to one kind of cytokine, secreted by activated mononuclear macrophages and the lymphocytes. It can affect the activity of lymphocyte, the macrophage or other cells, be responsible for the signal transmission, connect with different leukocytes group. It can also modulate the cell activation, multiplication and differentiation . When the interleukin binds with the receptor on the surface of cells, this kind of continual intercellular interaction , may amplify and modulate the immune response.IL-21 (interleukin-21) was one of recently discovered cytokine. In 2000, Julia and some other experts, from American Washington University, when they constructed one forecast signal peptide which has the amphoteric molecular spiral expression sequence, accidentally discovered IL-21 receptor . Subsequently, IL-21 was successfully cloned from activated CD₃⁺ T cells.Since IL-21 was discovered, as a result of its important biology function, it has been received world medicine reseacher's attention . Until now, many biological function of IL-21 has been discovered and announced to the public. IL-21 with the anti-CD₄ antibody may costimulate and promote the multiplication of mature B cells; IL-21 with the anti-CD₃ antibody costimulates and strengthens the multiplication of T cells. In vitro, IL-21 can be able to strengthen the multiplication and maturation of NK cells which originate from the marrow. NK cells participate in the natural surveillance of immunity system against malignant tumor, and thus it is helpful to the control of transferability tumor. Furthermore, it is essential to resist against microorganism pathogens (in particular virus). After marrow transplantation, they also influence the effect of transplanting anti-leukemia capability, and participate in the moderation of haematogenesis function. It indicated that IL-21 has the widespread treatment potential. For example, prevent oneself from bacterium and viral infection, treats autoallergic disease, enhance the effect of vaccines, and so on. Because of these, IL-21 has the very large development potential and the important practical significance.In this research, RNA which was separated from canine leukocytes,was reverse-transcribed, amplified by PCR, cloned into T plasmid and then sequenced, so canine IL-21 coded sequence was obtained. With DNAstar software, canine IL-21 coded sequence and its deduced amino acid sequence were analysized and compared with the published IL-21 coded sequence of human and house mouse.The result indicated that, the homology of canine IL-21 and human IL-21 nucleotide and the amino acid is highest (88.9%), but that of the canine and house mouse's IL-21 nucleotide and the amino acid is relatively low (77.1%). It means that IL-21 of canine and human has closer kinship than that of canine and house mouse.Because canine IL-21 has non- specific immunological enhancement , it may be together used with a variety of nucleic acid vaccines, because of the present unsatisfaction with nucleic acid vaccines . Therefore, it is very promising to use both together.Through this experiment, canine IL-21 was obtained. Next step, the cDNA of canine IL-21...