抗原性
毒力
突变体
微生物学
生物
马链球菌
基因
病毒学
遗传学
细菌
抗原
作者
Hongjie Fan,Tang Fu-yu,Ying Mao,Lu Chen
出处
期刊:Vaccine
[Elsevier]
日期:2009-01-01
卷期号:27 (1): 56-61
被引量:39
标识
DOI:10.1016/j.vaccine.2008.10.037
摘要
Streptococcus equi ssp. zooepidemicus (SEZ) causes serious disease in pigs. M-like protein (SzP) of SEZ is a virulence factor with opsonin function. To fabricate better vaccine against SEZ, We have generated a szp-knockout strain by homologous recombination. Two fragments, upstream and downstream of the szp gene, were obtained by genome walking. The vector was then used to delete a 1090 bp segment of szp gene from a strain of SEZ (ATCC35246). The mutant strain had 1000-fold decrease in LD50 as compared with wild type, and provided 85% protection against challenge with a virulent strain when administered as a live vaccine. Semi-quantitative RT-PCR analysis showed a marked increased in levels of IL-4 and IFN-gamma mRNA in immunized mice. These data demonstrate that szp-knockout strain is a better candidate for vaccine development.
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