99mTc labelled human leukocytes. An in vitro functional study

A new method of human leukocyte labelling is described. 20 ml of human blood are allowed to sediment in a dextran solution and the remaining red blood cells are removed using NH4C1. The leukocyte-rich suspension is incubated with a Sn-pyrophosphate solution, and then labelled, using 20 mCi 99mTc pertechnetate. Labelling efficiency is about 30%. Functional activity was shown to be satisfactory: (1) appearance under electron microscopy was quite normal; (2) Klebsiella ingestion, zymosan-stimulated oxygen consumption and iodination were similar in labelled and unlabelled cells, and (3) chemotaxis revealed no alteration in cell migration.