FOXP3 and neoplasm: To address whether Tregs were playing a role in the promotion of neoplasia in this study, APCmin/+ mice were treated with anti-CD25 monoclonal antibody throughout infection and the effects assessed at day 18 p.i. Antibody treatment significantly reduced the numbers of CD4+CD25+FoxP3+ cells in the MLN and spleen of treated animals (S3 Fig).