Preservation for vaccinal strains of Leptospira at liquid nitrogen

[摘要] INTRODUCTION: Leptospira interrogans strains of Cuban vaccine vax-SPIRAL®are preserved in Fletcher's semi-solid medium, which guarantees the preservation of the cell viability for a few months. OBJECTIVE: to evaluate the cryopreservation at liquid nitrogen of 6 different cryoprotectors as a long-term preservation method for Leptospira interrogans strains used as antigens in vaccine vax-SPIRAL® against leptospirosis. METHODS: viability was systematically evaluated according to the cell yield of the recently thawed strains in EMJH medium. Virulence stability was estimated in hamsters and antigenicity was evaluated by microscopic agglutination test using reference antisera from vaccinal serogroups. RESULTS: the use of 2.5% and 5% dimethyl sulfoxide, and 2.5% glycerol allowed quick recovery of the three strains without virulence or antigenicity depletion after 19 months of cryopreservation. CONCLUSIONS: the results showed the feasibility of the cryopreservation at liquid nitrogen using suitable cryoprotectant as a preservation method for vaccinal strains ofLeptospira.

[学科分类] 传染病学

[关键词] Leptospira interrogans;cepas vacunales;crioconservación