111In-oxine labelling of tumour-cytotoxic macrophages generated in vitro from circulating blood monocytes: an in vitro evaluation.

The labelling of ex-vivo activated macrophages with doses of 111In-oxine sufficient for gamma camera imaging does not damage cell viability or the functional competence of cells (secretion of tumour necrosis factor-alpha and interleukin-6). The mean labelling efficiency was about 84%. Release of 111In equivalent to 15% occurred over 24 h under cell culture conditions, indicating good stability of the radioactive cell label. 111In-oxine-labelled macrophages are a suitable tool for biokinetic studies of adoptive immunotherapy.