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Updated: May 13, 2026
Optimized Protocols for Mycobacterium leprae Strain Management: Frozen Stock Preservation and Maintenance in Athymic Nude Mice
Published on: March 23, 2014
[Preservation for vaccinal strains of Leptospira at liquid nitrogen]
Borrero Maura Reinier1, Niurka Batista Santiesteban, Kirenia Blain Torres
1Instituto Finlay, Centro De Investigación-Producción de Vacunas, Ciudad de La Habana, Cuba. rborrero@finlay.edu.cu
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 of Leptospira.
