A simple method for cryopreservation of Leishmania donovani promastigotes

Cryopreservation of promastigotes of L. donovani in NNN and Tobie's media was attempted. The media containing the promastigotes were kept directly at -80 degrees C. The cryopreserved media were examined for living promastigotes after 9, 12, 15, 20, 23, 26, 29, 32, 42, 56, 65 and 126 days after the culture tubes were brought directly from -80 degrees C to room temperature and examined after 30 min. All tubes showed living promastigotes which were used for further growth with no apparent morphological changes in subsequent subcultures. Viability was optimum. This method of short term cryopreservation is simple, reliable and reproducible for cryopreservation of culture adapted parasites and also important because different strains can be stocked without using any other chemical, or special equipment and liquid nitrogen chamber, for further use in immunological or other purposes.