Antigen-specific downregulation of T cells by doxorubicin delivered through a recombinant MHC II−peptide chimera
Sofia Casares1, Alexandru C. Stan2, Constantin A. Bona1
& Teodor- D. Brumeanu1
1
Mount Sinai School of Medicine, Department of Microbiology, New York, NY 10029.
2
Institute of Neuropathology, Hannover Medical School, Hannover 30625, Germany.
Correspondence should be addressed to Teodor- D. Brumeanu brumet01@doc.mssm.eduCD4 T cellsMHC class II−peptide chimeradoxorubicinT-cell downregulation
As the number of drugs with potential therapeutic use for T-cell-mediated diseases increases, there is a need to find methods of delivering such drugs to T cells. The major histocompatibility complex (MHC)−peptide complexes are the only antigen-specific ligands for the T-cell receptor (TCR) expressed on T cells, and they may be an appropriate drug delivery system. We engineered a soluble bivalent MHC class II−peptide chimera on the immunoglobulin scaffold (I-Ed/Fc2a/HA110-120, DEF) that binds stably and specifically to CD4 T cells recognizing the HA110-120 peptide. Doxorubicin, a powerful antimitogenic anthracycline, was enzymatically assembled on the galactose residues of a DEF chimera. The DEF-gal-Dox construct preserved both the binding capacity to hemagglutinin (HA)-specific T cells, and the drug toxicity. Brief exposure of HA-specific T cells to DEF-gal-Dox construct in vitro was followed by drug internalization in the lysosomes, translocation to the nucleus, and apoptosis. Administration of DEF-gal-Dox to mice expressing the TCR-HA transgene reduced the frequency of TCR-HA T cells in the spleen and thymus by 27% and 42%, and inhibited HA proliferative capacity by 40% and 60%, respectively. It has not been demonstrated previously that pharmacologically active drugs able to modulate T-cell functions can be delivered to T cells in an antigen-specific manner by soluble, bivalent MHC II−peptide chimeras.
/Fc
2a/HA110-120, DEF) that binds stably and specifically to CD4 T cells recognizing the HA110-120 peptide. Doxorubicin, a powerful antimitogenic anthracycline, was enzymatically assembled on the galactose residues of a DEF chimera. The DEF-gal-Dox construct preserved both the binding capacity to hemagglutinin (HA)-specific T cells, and the drug toxicity. Brief exposure of HA-specific T cells to DEF-gal-Dox construct in vitro was followed by drug internalization in the lysosomes, translocation to the nucleus, and apoptosis. Administration of DEF-gal-Dox to mice expressing the TCR-HA transgene reduced the frequency of TCR-HA T cells in the spleen and thymus by 27% and 42%, and inhibited HA proliferative capacity by 40% and 60%, respectively. It has not been demonstrated previously that pharmacologically active drugs able to modulate T-cell functions can be delivered to T cells in an antigen-specific manner by soluble, bivalent MHC II−peptide chimeras.
