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In vitro selective depletion of CD4+CD25+ regulatory T-cells from PBMC using anti-tac-SAP.

Authors :
Akbari, Akbar
Rezaei, Abbas
Source :
Journal of Immunotoxicology; Dec2012, Vol. 9 Issue 4, p368-373, 6p
Publication Year :
2012

Abstract

It has been shown that naturally occurring regulatory T-cells (CD4<superscript>+</superscript>CD25<superscript>+</superscript> Foxp3<superscript>+</superscript> T-cells) have critical roles in tumor invasion and down-regulation of immune response against established tumors. High expression of CD25 (IL-2R α) by regulatory T (T<subscript>reg</subscript>) cells may cause an inefficient response when using IL-2-based cancer vaccines. It seems that selective elimination of T<subscript>reg</subscript> cells before treatment of tumor-bearing T-cells can strongly increase the efficacy of a vaccine. The aim of this study was to set up an efficient cost-effective protocol to eliminate CD4<superscript>+</superscript>CD25<superscript>+</superscript> T-cells-using the immunotoxin anti-tac-SAP. Peripheral blood mononuclear cells (PBMC) taken from colon cancer patients were treated with different concentrations (i.e., 0-100 µg/dl) of the immunotoxin. Flow cytometric analyses were then preformed to analyze expression of CD4, CD25, CD3, CD8, and CD45 surface markers; semi-quantitative fluorescent-PCR was used for the detection of Foxp3 expression before and after anti-tac-SAP treatment. The results indicated that anti-tac-SAP effectively eliminated CD4<superscript>+</superscript>CD25<superscript>+</superscript> T<subscript>reg</subscript> cells and that 25 µg/dl was the optimal concentration of anti-tac-SAP for selective depletion of these cells. These outcomes were verified by analyses of Foxp3 expression. The results also indicated that this immunotoxin had no non-specific effects on other T-cells, including CD4<superscript>+</superscript>CD25<superscript>−</superscript> and CD8<superscript>+</superscript>CD45<superscript>+</superscript> T-cells. Building on the work here, ongoing/future studies with the anti-tac-SAP will focus on functional assessments of the remaining (i.e., non-eliminated) T-cells (i.e., CD8, CD4; using proliferation and peptide sensitization assays) to ascertain if the immunotoxin inadvertently alters the functions of these cells-an untoward outcome. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
1547691X
Volume :
9
Issue :
4
Database :
Complementary Index
Journal :
Journal of Immunotoxicology
Publication Type :
Academic Journal
Accession number :
83183481
Full Text :
https://doi.org/10.3109/1547691X.2012.668974