Research Article

Low-Dose Cyclophosphamide Synergizes with Dendritic Cell-Based Immunotherapy in Antitumor Activity

Figure 1

Increase in the proportion of regulatory T cells in a murine model for mesothelioma. (a) Left: The transcription factor Foxp3, a hallmark of naturally arising CD4+CD25+ Tregs, was expressed inside the tumor (red staining). Cells were counterstained with haematoxylin. [Magnification 2 0 0 × ] Right: A higher magnification ( 4 0 0 × ) shows the appearance of Foxp3+ cells as indicated by arrows. (b) Tregs (blue staining) were occasionally present in the near vicinity of CD8+ cells (red staining) [Magnification 1 0 0 0 × ]. (c) and (d) Percentage of Tregs (defined as CD4+CD25+Foxp3+ cells) from total CD4+ T cells in the peripheral blood and draining lymph nodes is significantly higher at day 10 in tumor-bearing mice compared to healthy mice as observed by flow cytometry. (e) A positive correlation was found between the total tumor weight and the percentage of Tregs, measured in the lymph nodes of tumor-bearing mice. Five mice were euthanized at day 10 (tumor weight varied from 0.1 gram to 1 gram) and three mice at stage with ill health (tumor weight 1.5 to 2.1 gram). Correlation coefficient of the trend line ( 𝑅 -squared) is 0.780 ( 𝑃 v a l u e i s . 0 0 3 9 ).