Circulating regulatory T cells (CD4+CD25+FOXP3+) decrease in breast cancer patients after vaccination with a modified MHC class II HER2/neu (AE37) peptide.

Abstract Regulatory T cells (T Reg ), CD4 + CD25 + FOXP3 + , are implicated in suppressing tumor immune responses. We analyzed peripheral blood lymphocytes (PBL) from breast cancer patients receiving a modified HLA class II HER2/ neu peptide (AE37) vaccine for T Reg cells and correlated their levels with vaccine-specific immune responses. The mean CD4 + CD25 + FOXP3 + T Reg cells decreased in patients with vaccination with no significant difference in serum TGF-β levels. IFN-γ ELISPOT and DTH increased after vaccination with a good correlation between T Reg cell reduction and size of DTH to AE37. The T Reg cell reduction and associated immune response suggest that AE37 may be clinically useful.