Edwards M F, Stocker B A
Department of Microbiology and Immunology, Stanford University School of Medicine, California 94305.
J Bacteriol. 1988 Sep;170(9):3991-5. doi: 10.1128/jb.170.9.3991-3995.1988.
Salmonella typhi strains with two deletion mutations, each causing an attenuating auxotrophy, have been constructed from strains Ty2 and CDC 10-80 for possible use as oral-route live vaccines. An aroA(serC)::Tn10 transposon insertion was first transduced from a Salmonella typhimurium donor into each wild-type S. typhi strain. Transductants of the Aro- SerC- phenotype were treated with transducing phage grown on an S. typhimurium strain with an extensive deletion at aroA; selection for SerC+ yielded transductants, some of which were delta aroA. A his mutation was next inserted into a delta aroA strain in each line by two steps of transduction. Two deletions affecting de novo purine biosynthesis were used as second attenuating mutations: delta purHD343, causing a requirement for hypoxanthine (or any other purine) and thiamine, and delta purA155, causing an adenine requirement. The purHD343 deletion was introduced into the delta aroA his derivatives of each strain by cotransduction with purH::Tn10, and the purA155 deletion was introduced into the CDC 10-80 delta aroA his derivative by cotransduction with an adjacent silent Tn10 insertion by selection for tetracycline resistance. Tetracycline-sensitive mutants of each of the three delta aroA his delta pur strains were isolated by selection for resistance to fusaric acid. The tetracycline-sensitive derivative of the CDC 10-80 delta aroA his delta purA155 strain, designated 541Ty, and its Vi-negative mutant, 543Ty, constitute the candidate oral-route live-vaccine strains used in a recent volunteer trail (M. M. Levine, D. Herrington, J. R. Murphy, J. G. Morris, G. Losonsky, B. Tall, A. A. Lindberg, S. Stevenson, S. Baqar, M. F. Edwards, and B. A. D. Stocker, J. Clin. Invest. 79:885-902, 1987). Tetracycline-sensitive mutants of the delta aroA his delta purHD derivative of strains Ty2 and CDC 10-80 may also be appropriate as live vaccines but have not been tested as such.
已从Ty2菌株和CDC 10 - 80菌株构建出带有两个缺失突变的伤寒沙门氏菌菌株，每个突变都会导致营养缺陷型减毒，这些菌株有可能用作口服活疫苗。首先将aroA(serC)::Tn10转座子插入从鼠伤寒沙门氏菌供体转导到每个野生型伤寒沙门氏菌菌株中。对Aro - SerC - 表型的转导子用在aroA处有广泛缺失的鼠伤寒沙门氏菌菌株上生长的转导噬菌体进行处理；选择SerC + 得到转导子，其中一些是ΔaroA。接下来通过两步转导将his突变插入每个品系的ΔaroA菌株中。两个影响嘌呤从头合成的缺失用作第二个减毒突变：ΔpurHD343，导致对次黄嘌呤（或任何其他嘌呤）和硫胺素的需求，以及ΔpurA155，导致对腺嘌呤的需求。通过与purH::Tn10共转导将purHD343缺失引入每个菌株的ΔaroA his衍生物中，通过与相邻的沉默Tn10插入共转导并选择对四环素的抗性，将purA155缺失引入CDC 10 - 80 ΔaroA his衍生物中。通过选择对镰刀酸的抗性，分离出三个ΔaroA his Δpur菌株中每个菌株的四环素敏感突变体。CDC 10 - 80 ΔaroA his ΔpurA155菌株的四环素敏感衍生物，命名为541Ty，及其Vi阴性突变体543Ty，构成了最近志愿者试验中使用的候选口服活疫苗菌株（M. M. Levine、D. Herrington、J. R. Murphy、J. G. Morris、G. Losonsky、B. Tall、A. A. Lindberg、S. Stevenson、S. Baqar、M. F. Edwards和B. A. D. Stocker，《临床研究杂志》79:885 - 902，1987）。Ty2菌株和CDC 10 - 80菌株的ΔaroA his ΔpurHD衍生物的四环素敏感突变体也可能适合作为活疫苗，但尚未进行此类测试。
