[Formation of colonies of P-388 leukemic cells in semisolid agar]

Substrain P-388/A2 adapted to cultivation of agar gel in the form of compact colonies was obtained as a result of alternating passages of cells of ascitic mouse leukemia P-388 in the primary semifluid agar culture and in the mouse abdominal cavity. The efficacy of colony formation and the size of the colonies depended on the initial density of the cell suspension. In case of introduction into the agar medium of 100 cells/ml the planting efficacy constituted 20%, and the number of cells in the colony by the 8th--10th days of cultivation reached 13 000.