Superoxide assay-leukocyte adherence inhibition test and a soluble factor which stimulates the adherence of macrophages.

A modified method for the leukocyte adherence inhibition test is described. Peritoneal cells from immune guinea pigs or peripheral mononuclear cells from cancer patients were incubated with immunizing antigen or tumor extract in a 4-mm-wide glass microcell for spectrophotometer analysis. Instead of visual cell counting, the cells adherent to the bottom of the microcell were stimulated with cytochalasin E and wheat germ agglutinin, and the amount of the superoxide (O2.-) generated from the adherent macrophages or monocytes was assayed. Antigen-specific adherence inhibition of peritoneal cells of the immunized guinea pigs was detected 2 weeks after immunization. In contrast, cell adherence was stimulated after 3 weeks. It was shown that a soluble factor was responsible for the adherence stimulation and that nonadherent cells were necessary for its production. Peripheral mononuclear cells of 70% of the tumor-bearing lung cancer patients reacted to the lung tumor extract (9 adherence inhibitions and 7 adherence stimulations per 23 patients). Twenty-five % (3 of 12) of tumor-free patients showed positive reactions, all with adherence stimulation. Of the 12 healthy donors, 3 cases of pneumonia, one case of angiosarcoma of the left flank, one case of hemangiopericytoma of the mediastinum, and 8 cases of breast cancer, non reacted with the lung tumor extract, and only one of 7 lung tuberculosis patients showed positive adherence stimulation.