"Activated" monocytes in gastric cancer patients. II. Suppressor and cytostatic activity in vitro

Suppression of monocyte mediated anti U562 cytotoxicity by soluble factors in the serum of cancer patients and in the supernatant of K562 cell culture

Anti U562 cytotoxicity of monocytes isolated from blood of patients with alimentary tract cancer was shown to be depressed compared to monocytes of healthy individuals. A serum factor was demonstrated in the patients which depressed the cytotoxicity of healthy donor monocytes. Such suppressive factor was also produced by the K562 cell line and its production was blocked by indomethacin, a prostaglandin synthesis inhibitor, as well as by thymus preparations TFX and Thymex L.

Serial immunological testing in patients with gastric cancer

Standard immunological parameters measuring non-specific cellular immune reactivity were determined in 175 patients with different stages of gastric cancer prior to surgery and during follow-up. Several tests measuring monocyte activity were also employed. The total number of T cells and their subpopulations Ta and T29o was unchanged except depression of T29o in stage IV. The blastogenic response of lymphocytes to PHA as assessed by stimulation of protein synthesis was only depressed in stage IV. In contrast the PHA-induced lymphokine production was increased in all patients but the differences were significant for stage III and IV. Monocyte Fc receptor expression was increased in stages II-IV, while nitro blue tetrazolium reduction and antibody dependent cellular cytotoxicity of monocytes was elevated in stage IV. The number of extractable monocytes was not increased. Longitudinal studies suggested that most of the parameters normalized during follow-up. No major long-term impact of chemoimmunotherapy (5-FU + BCG) on the immune parameters was observed except a transient increase in PPD reactivity approximately 1 year after commencement of treatment. In patients with stage III gastric cancer the increased occurrence of suppressor cells (mostly monocytes) and elevated cytostatic activity of monocytes was associated with a longer survival while the increased lymphokine production and Fc receptor expression were seen in the group of patients succumbing earlier. We concluded that most of the changes in immune parameters were seen only in advanced disease and paradoxically disappeared in the course of disease. The determination of monocyte activity seems to be a sensitive indicator of immune system dearrangements in earlier stages of cancer and a useful prognostic factor in gastric cancer.

Study of spontaneous rosette formation and changes of sialic acid content in the surface glycoproteins of macrophages induced by hamster transplantable melanomas

The influence of two kinds of transplantable melanomas on the content of sialic acids in the surface glycoproteins of hamster peritoneal macrophages was studied, and the ability of these cells to form spontaneous rosettes. It has been found that the intensification of rosette formation by macrophages with SRBC depends on the melanoma line. No correlation has, however, been found between changes in the sialic acids content and the ability of macrophages to form rosettes under the influence of melanomas differing in malignancy.