Interleukin-2 fusion protein with anti-CD3 single-chain Fv (sFv) selectively protects T cells from dexamethasone-induced apoptosis.
Apoptosis of mature T cells may be an important pathophysiologic mechanism in diseases such as AIDS, cancer, and autoimmunity. In this study, in order to selectively protect T cells from dexamethasone (DEX)-induced apoptosis we constructed a fusion protein (anti-CD3sFv-IL-2) in which anti-CD3 single-chain Fv (sFv), the smallest unit of antibody recognizing the CD3 epsilon moiety of the T-cell receptor (TCR), was covalently linked to murine interleukin-2 (IL-2). Recombinant anti-CD3sFv protein was also expressed and used as a control. The purified anti-CD3sFv-IL-2 protein displayed IL-2 bioactivity in an IL-2 proliferation assay, which was inhibited by a neutralizing mIL-2 mAb. The anti-CD3sFv-IL-2 protein protected T lymphoma cells (S49.1) from DEX-induced apoptosis as demonstrated by oligonucleosomal genomic DNA fragmentation assay, and also recovered proliferation capacity of DEX-treated S49.1 cells and increased T cell composition both in DEX-treated spleen cell-populations and in DEX-treated mice, while the anti-CD3sFv protein did not. In addition, the anti-CD3sFv-IL-2 fusion protein was more efficient than a simple mixture of anti-CD3sFv and free rIL-2 in selectively protecting T cells from DEX-induced apoptosis. The levels of bcl-2 gene expression were significantly increased in DEX-treated T cells in the presence of the anti-CD3sFv-IL-2 protein. These studies indicate that the anti-CD3sFv-IL-2 fusion protein can selectively protect T cells from DEX-induced apoptosis and that the covalent linkage of anti-CD3sFv and IL-2 confines the anti-apoptotic effect of IL-2 to T cells.
Kim
E J
EJ
College of Pharmacy, Chonnam National University, Kwangju 500-757, South Korea.
Cho
D
D
Hwang
S Y
SY
Kim
T S
TS
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D017252:CD3 Complex / Q000276:immunology*; D003907:Dexamethasone / Q000494:pharmacology*; D005260:Female; D019254:Genes, bcl-2; D007128:Immunoglobulin Fragments / Q000494:pharmacology*; D007376:Interleukin-2 / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D011993:Recombinant Fusion Proteins / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects*
D017252:CD3 Complex; D007128:Immunoglobulin Fragments; D007376:Interleukin-2; D011993:Recombinant Fusion Proteins; C055966:immunoglobulin Fv; D003907:Dexamethasone