Giant cell formation by peripheral human monocytes

Peripheral monocytes from patients with breast carcinoma were incubated in vitro using an under agarose technique. The monocytes were incubated at 37 degrees C in a 5% CO2 atmosphere using a mixture of 0.75% agarose gel in Eagle's medium supplemented with 10% group AB pooled human serum and 50 micrograms/ml zymosan-activated serum. Significant giant cell formation occurred after 6 days incubation and was most marked after 9 days. The optimum pH for giant cell formation was between 7.0 and 7.4. The age of the subject (range 20-50 years), type of coagulant, delay in monocyte separation, storage of the monocyte preparation for up to 24 h at 4 degrees C, and freezing for up to 3 months, had no effect on giant cell formation. No giant cell formation was observed in control subjects.