Tube leukocyte adherence inhibition assay for the detection of anti-tumor immunity. I. Monocyte is the reactive cell.

Peripheral blood leukocytes (PBL) from breast cancer patients with early or localized cancer fail to adhere to glass in the presence of breast cancer extract. The same leukocytes do not react to unrelated tumour extracts. Enrichment and depletion of certain PBL populations from patients with apparently localized breast cancer indicated that the indicator and/or reactive cell manifesting non-adherence in the presence of appropriate tumour antigen was phagocytic, glass adherent in the absence of tumour antigen and had cell surface Fc-receptors. The cell involved, therefore, appears to be the circulating monocyte. These results show that in the tube LAI assay, the peripheral blood monocyte appears to react directly with the tumour antigen resulting in a loss of its property of adherence to glass.