Analysis of immunosuppressive mechanism to cytotoxic T lymphocyte generation in patients with advanced cancer.
In vitro activation of cytotoxic T lymphocytes (CTLs) in peripheral blood mononuclear cells (PBMCs) of patients with advanced cancer is extremely difficult. The proportion of monocytes among PBMCs is high in this type of patient. We investigated monocytosis and the mechanism of suppression of CTL generation and obtained the following findings. 1. The cell fraction ratios of PBMCs were divided into two groups: those with a higher proportion of T cells (Group I), and those with a rapid increase in monocytes and a decrease in T cells (Group II). 2. CTL generation occurred in Group I, but was either extremely low or not observed in Group II. 3. Supernatant from the culture of monocytes obtained from Group II remarkably suppressed CTL generation. 4. Statistical analysis revealed that the cancer recurrence rate over a 2-year period was significantly higher in Group II than in Group I. These findings show that monocytes are associated with the recurrence and worsening of cancer. Furthermore, the monocytes exert this effect by releasing a humoral factor that suppresses CTL activation.
Maeda
N
N
Department of Obstetrics and Gynecology, Kochi Medical School, Japan.
Sagara
Y
Y
D005260:Female; D005833:Genital Neoplasms, Female / Q000276:immunology*; D006801:Humans; D007165:Immunosuppression Therapy; D008213:Lymphocyte Activation; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014407:Tumor Cells, Cultured