| Based on the published nucleotide sequence of chicken interleukin-2 ,a pair of primers was designed and synthesized .With the technology of RT-PCR,a cDNA fragment of 441bp was amplified from the spleen lymphocytes actived with ConA of 30-day-old Chongren chicken and Leghorn SPF chicken respectively, and cloned to pMD-18T vector respectively. They are identified to be interleukin-2 cDNA with the methods of restriction enzyme digestion ,PCR and sequencing. They are identical to the nucleotide sequences reported in Genebank. Comparing with the sequences of chickens reported in Genebank,there are mutation nucleotides of one to five, and shared 85.9%and 86.6% homology with turkey respectively. Amino acid analysis indicated that there are changes of one to five amino acid comparing with other interleukin-2 sequences of chicken reported in Genebank ,and shared 98.6-99.7% homology with each other,shared 68.8%and 69.4% homology with turkey respectively. The predicted second structure of encoding amino acid indicated ,there is a leader sequence of 22 amino acid,and four conversed cysteines allowing the formation of intra chain disulfide, four a -helices being similarity to the ones of mammals The phylogenetic tree analysis and IL-2 antigenic analysis indicated that chicken IL-2s have evolutionary relationship with mammals TL-2s,so it confirmed the opinion that IL-2s have specificity of species.By the technology of DNA recombination ,the ChIL-2 cDAN was cloned toexpression plasmid pBV220 vector ,and transformed to E.coli. DH5 a .The recombinant protein was expressed by inducing with the changes of tempreture .The results of SDS-PAGE indicated that the production of recombinant IL-2 reached its peak about 4-5 hours after inducing at 42癈.and the expression protein can possess about 10 percent of the total protein. Most of the recombinant protein exists in sentiment,and a little in supernatant After ultrasonicated,the sentiment was isolated and purified primarily ,then renatured.followed The biological activity of supernatant and renatured protein was detected with lymphocyte transform assays.The results indicated that recombinant chicken IL-2 have the high ability to supply the propagation of spleen lymphocytes actived with ConA of chicken, peagon,duck,goose and quail,but the ability is low to rat. The experiments have identified that recombinant IL-2 has biological activity ,and provide the .evidences for further experiments in chicken or other avians.In this study, recombinant IL-2 expressed in prokaryotic was injected with oil vaccine.to study the effect on four in one oil adjuvant Inactivited vaccine.In the experiment,five groups were designed ,ten chickens for one group . the control group was immunized only with oil adjuvant vaccine ,the other four groups injected different dose of IL-2 at the same time, as follows O.OSmg ,0.1 Omg, 0.15mg,0.20mg. the experiment groups and the control groupwere all inoculated oil adjuvant vaccine 0.5ml respectively.Detecting the antibody titers of Newcastle disease and Avian influenza by HA and HI assay ,the results indicate that the recombinant IL-2 has strong effect on oil adjuvant vaccine , the titers of antibodys increased greatly by 2.4-2.8 titers and 2.3-3.0 titers respectively . During the whole experiment the toxic effects was not found .The results confirme that recombinant IL-2 is very effective in enhancing the immune antibody titers.
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