[Modification of a method for determining the cytotoxic activity of lymphocytes--natural killers in space experiments].

A space modification of a method for determining the cytotoxic activity of natural killers (NK) uses cultures of human lymphocytes and re-inoculated suspension of tumorous myeloblasts K-562. The 3H-uridine labeled target-cells fixated in 0.1 % formalin solution proved to be best suited to the conditions prohibiting regular recharge of cultural medium and utilization of radioactive agents. The following practical conclusions were made from the space-flown experiment: pre-launch procedures (lymphocyte isolation and delivery to the launch site) and time period till dock must not be longer than 5 days (1) and during transportation to the orbiting vehicle cell cultures must be kept at 18-20 degrees C (2). The modified method can be employed to study various aspects of cell interaction such as the NK ability to destroy target-cells in suspension cultured exposed in microgravity.