Effects Of Chicken Interleukin-18Prokaryotic Expression Protein To Immune Function In Chickens

[Objective]:Cloing chicken interleukin18(ChIL-18) gene, and expressing ChIL-18protein in Escherichia coli BL21; according to animal experiments to study biological activity of ChIL-18and its effect on vaccine immunization with the aim to provide theoretical guidance for clinical application of ChIL-18.[Methods]:According to ChIL-18mRNA sequence published in GenBank, a pair of specific primers was designed; the total RNA which was extracted from chicken spleen was treated as templates and the target gene fragments was amplified by RT-PCR. Prokaryotic expression vector pET32a-ChIL-18was established, then expression product was renatured and purified. The chicken were immunized using ShenZhiLing and purified ChIL-18protein at the same time, and then detected the immune indexes periodically.[Results]:(1) The ChIL-18gene fragment of635bp is cloned by RT-PCR and the sequence is proved to be right by BLAST analysis in GenBank. The homology is99%and the analysis of the amino acid homology is100%, it showed that the cloing of ChIL-18gene was successful.(2) The double digests and the identification of PCR expressed that the recombinant plasmid pET32a-ChIL-18was successfully constructed;the result of SDS-PAGE showed that the induction expression protein was about40kD, the result was conformed to the expectation of experiment.(3) Animal test indicated that ChIL-18expression protein can enhance red blood cell C3b receptor ratio and reduce red blood cell IC receptor ratio, improve the peripheral blood T/B lymphocytes and NIB and ND vaccine antibody levels of the chicken, accelerate the growth of chicken, and protect the chicken from infecting NIB virulent strain.[Conclusions]:The ChIL-18protein obtained by prokaryotic expressing can enhance the immunity of the chicken and improve immune effect of NIB and ND vaccine.