Response of T lymphocytes to phytohaemagglutinin (PHA) and to cancer-tissue-associated antigens, measured by the intracellular fluorescence polarization technique (SCM test)

Abstract

Human peripheral-blood mononuclear cells, separated by Isopaque-Ficoll flotation and E-rosette formation, were tested by the fluorescein fluorescence polarization method of Cercek & Cercek (the SCM test). The response to stimulation with PHA or cancer tissue leads to a decreased polarization value TP). The responding cells were present in the T-cell fraction (E-rosette-forming cells), which contained less than 10% macrophages and less than 1% cells with surface-bound Ig. Control experiments with the non-T-cell fraction gave different response patterns. The response of T cells from apparently healthy donors and patients with and without cancer were compared. All of the group of 16 healthy persons had a polarization value (P) which decreased (mean +/- s.e. = 23% +/- 2) after PHA stimulation, compared with no or little decrease after stimulation with cancer tissue, giving cancer indices (P cancer/PPHA) of 1.15--1.56. In 13 patients with carcinoma of the colon, stimulation with PHA produced little decrease of polarization, while stimulation with colonic cancer tissue decreased the polarization in all cases (mean +/- s.e. = 25% +/- 2). The corresponding cancer indices were 0.61--0.86. Seven of 10 colonic-cancer patients tested against ovarian cancer tissue did not respond, whilst 3 patients in this group responded and had a cancer index less than 1.0. Three patients with non-malignant diseases had response patterns similar to those of healthy persons, except for the lack of PHA response in the patient with ulcerative colitis. This method seems to open up new possibilities for evaluation of cancer patients, although further studies including many more patients are needed before any conclusion can be drawn as to the validity of the test.