[Interaction between tumor-associated macrophages (TAMs) and HUT-78 lymphoma cells]

This study was aimed to explore the effects of lymphoma cells on the differentiation of monocytes from peripheral blood to tumor-associated macrophages (TAM) and the effect of TAM on proliferation of lymphoma cells in vitro, and investigate the difference between newly diagnosed lymphoma patients and healthy volunteers. Blood samples were obtained from 15 newly diagnosed lymphoma patients and 8 healthy volunteers. Monocytes from peripheral blood were isolated by Ficoll- Hypaque density gradient centrifugation and CD14 immuno-magnetic beads. Then monocytes were directly co-cultured with HUT-78 lymphoma cells by using Transwell apparatus in vitro. Expression of the markers of TAM (CD68 and CD163) were detected by flow cytometry to analyse the proportion of differentiated TAM. Growth curve of HUT-78 cells was made by direct cell count. The IL-10 and VEGF levels in the co-culture system were detected by ELISA. The detection results of newly diagnosed lymphoma patients were compared with that of healthy controls. The results showed that the proportion of CD68(+), CD163(+) and CD68+CD163 (+) cells were significantly up-regulated after co-cultured with HUT-78 lymphoma cells in both patients and healthy controls (P < 0.05). There was no statistical significance in the increasing degree between patients and healthy controls. TAM differentiated from peripheral blood monocytes showed no significant promotion or inhibition on the growth of co-cultured lymphoma cells. For patients, the IL-10 and VEGF levels in the co-culture group were significantly lower than those in two single culture groups (P < 0.05) . For healthy controls, there was no significant difference between these two. It is concluded that lymphoma cells can promote the differentiation of monocytes to macrophages with M2-like phenotype. There is no difference in the promoting degree between patients and healthy controls. TAM differentiated from patients' monocytes significantly down-regulate levels of IL-10 and VEGF in the co-culture system, exhibited functions more like M1 macrophages. In contrast, TAM differentiated from monocytes of healthy controls show no such effects on the co-culture system.