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

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-beta levels. IFN-gamma 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. Published by Elsevier Ltd.