Construction and identification of the attenuated Salmonella typhimurium strains expressing mouse sperm cyritestin

Aim To construct a live oral Salmonella typhimurium vaccine strain expressing mouse sperm cyritestin. Methods The gene encoding the mature cyritestin protein was obtained by digestion of the plasmid TAZ83/13 using restrictive enzyme and was inserted into the plasmid pYA3149. The resulting recombinant plasmid pCFL was transformed into the delta cya, delta crp, delta asd attenuated Salmonella typhimurium vaccine strains X4632 and X4550, to construct the live vaccine strains X4632(pCFL) and X4550(pCFL). Results The recombinant plasmid pCFL was stable in the X4632(pCFL) and X4550(pCFL)strains under culture condition. The recombinant strain X4550(pCFL)could colonize and persist stably in Peyer's patches, mesenteric lymph nodes and spleens of BALB/c mice. The X4550(pCFL) could also colonize and persist stably in Peyer's patches. Both strains could express recombinant mature cyritestin protein recognized by the anti cyritestin monoclonal antibody and had no toxicity. Conclusions The live vaccine strains X4632(pCFL)and X4550(pCFL)are worthy to be studied as a contraceptive vaccine.