| 摘要 |
The invention involves the discovery that Chlamydia sp. strains can be cured of their plasmids by treatment with novobiocin, and that plasmid-deficient strains are defective in infecting cells under standard conditions, but can infect cells if centrifuged onto the host cells. The plasmid-deficient strains were able to infect mice with little or no pathological symptoms, and reduced the pathology in mice later challenged with the parental wild-type disease-causing Chlamydia strain. Thus, plasmid-deficient Chlamydia are effective vaccine strains. The invention provides a process for isolating a plasmid-deficient strain of Chlamydia sp., a process for developing a plasmid-deficient strain of Chlamydia sp. for use as a vaccine, a process for developing a highly infective plasmid-deficient strain of Chlamydia sp., isolated Chlamydia sp. strains, a method of expressing a recombinant nucleic acid in Chlamydia sp., and a method of immunizing a mammal against a Chlamydia infection. |
