To the Editor – Eur. J. Immunol. 1/2006

Abstract

We read with great interest the recent article by Roncador et al. [1]. These authors report on the characterization of seven generated anti-FOXP3 monoclonal antibodies and the distribution of FOXP3 expressing CD4CD25 cells in vivo. In addition, a commercially available goat polyclonal FOXP3 Ab (Abcam, ab2481) was evaluated and described to label human FOXP3 protein only in frozen tissue. In contrast to Roncador et al., we were able to successfully apply the Abcam goat polyclonal FOXP3 Ab to routinely fixed paraffin-embedded tissues. In a study on peripheral and intestinal regulatory CD4 CD25 T cells in inflammatory bowel disease, we used an amplification method combining a secondary rabbit anti-goat Ab followed by the EnVision peroxidase kit (DakoCytomation) for the detection of FOXP3 protein [2]. We have confirmed the immunophenotype of the regulatory T cells by double-labeling FOXP3/CD3 and FOXP3/CD25. In line with Roncador et al., we also observed scattered FOXP3 cells within the interfollicular area of tonsils serving as controls (Fig. 1) and few positive cells