Abstract: The present study aims to investigate the genetic stability of the plasmid expressing chicken interleukin-2 (ChIL-2) and chicken interleukin-4 (ChIL-4) fusion genes carried by the DH5α/pUC57 recombinant strain during the large-scale production process, and to explore its potential as an immune adjuvant for live chicken coccidiosis vaccine in commercial batch production. The laboratory genetic stability identification of the recombinant DH5α/pUC57 was carried out by subculturing the recombinant plasmid for 30 consecutive generations. The results showed that after the recombinant strain being cultured for 30 consecutive generations on the lysic broth (LB) plates containing ampicillin (Amp+), the recombinant bacterias remained Gram-negative (G-), and could ferment glucose and mannitol to result in specific phenomena, whereas none fermented lactose was found.The homology of the 16S rDNA fragments between the recombinant bacteria and E. coli was greater than 95%, the supercoil ratio of the recombinant plasmids of each generation was greater than 90%, and the plasmid loss rate was 0. The expression product of the recombinant plasmid could stimulate the differentiation of spleen lymphocytes of SPF chicks. The above results indicate that there were essentially no changes in the structure of the 30 generations of continuous passages for the ChIL-2-ChIL-4 fusion gene recombinant bacteria and recombinant plasmids, and the plasmids can be isolated stably, which can provide material support for the expansion of production.
key words: ChIL-2; ChIL-4; recombinant plasmid; genetic stability; vaccine adjuvant
（Acta Laser Biology Sinica, 2021, 30(5): 475-480）