L1210 is a mouse lymphocytic leukemia cell line which is derived from the ascitic fluid of 8-month-old female mice. While they are lymphocytic B-cells they are more like lymphoblasts in morphology. L1210 is a mouse lymphocytic leukemia cell line which is derived from the ascitic fluid of 8-month-old female mice. While they are lymphocytic B-cells they are more like lymphoblasts in morphology.