Abstract

BORRERO MAURA, Reinier et al. Preservation of vaccine strains of Leptospira at - 70 °C. Rev Cubana Med Trop [online]. 2006, vol.58, n.1. ISSN 0375-0760.

The goal of this study was to evaluate the cryopreservation at -70^oC with the use of 9 different cryoprotectants as a preservation method for the strains of Leptospira interrogans used as antigens in the leptospiral vaccine vax-SPIRAL^â. Viability was systematically evaluated according to the cell yield achieved by the just thawed strains in EMJH medium. Virulence stability was estimated in Hamsters and antigenicity was evaluated by microscopic agglutination test using reference antisera before and after cryopreservation. Only the use of 2,5% and 5% dimethyl sulfoxide or 5% skim milk allowed a quick recovery of the three strains without virulence or antigenicity depletions after 7 months of cryopreservation while glycerol had a variable effect on the degree of recovery of each strain. The results showed the feasibility of the cryopreservation at -70 °C with the use of a suitable cryoprotectant as a preservation method for vaccine strains of Leptospira.

Keywords : Leptospira interrogans; vaccine strains; cryopreservation.

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