Sequential effects of interleukin 2-diphtheria toxin fusion protein on T-cell activation.
The interleukin 2-diphtheria toxin-related fusion protein (IL-2-toxin) rapidly inhibits protein synthesis in IL-2 receptor (IL-2R)-bearing phytohemagglutinin-activated T cells but transiently stimulates DNA synthesis. At 7 hr after interaction with IL-2R+ phytohemagglutinin-activated T cells, IL-2-toxin-treated cells bear augmented steady-state levels of c-myc, interferon gamma, and IL-2R mRNA; these effects are indistinguishable from those produced by recombinant IL-2. Amplification of IL-2 sequences by the polymerase chain reaction reveals an increased level of IL-2 mRNA in cell cultures treated with recombinant IL-2, IL-2-toxin, and cycloheximide. These results suggest that IL-2-toxin can affect de novo IL-2 gene transcription/mRNA stabilization through independent mechanisms exerted by both the IL-2R binding domain and ADP-ribosyltransferase activity of the fusion protein. After 20 hr of culture, IL-2R mRNA was markedly decreased in both IL-2-toxin- and cycloheximide-treated phytohemagglutinin-activated T cells. Although interaction of IL-2-toxin with IL-2R+ T cells initially mimics the stimulatory effects of IL-2 upon c-myc, interferon gamma, IL-2R, and IL-2 gene expression, the consequences of inhibition of protein synthesis mediated by the ADP-ribosyltransferase activity of the toxin dominate after 7 hr and are indistinguishable from those effects mediated by cycloheximide.
Walz
G
G
Charles A. Dana Research Institute, Beth Israel Hospital, Boston, MA.
Zanker
B
B
Brand
K
K
Waters
C
C
Genbauffe
F
F
Zeldis
J B
JB
Murphy
J R
JR
Strom
T B
TB
D001483:Base Sequence; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D004261:DNA Replication / Q000187:drug effects; D004167:Diphtheria Toxin / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D005796:Genes; D006801:Humans; D000922:Immunotoxins / Q000494:pharmacology*; D007376:Interleukin-2 / Q000235:genetics* / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects*; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*
C054780:DAB(486)-interleukin 2; D004167:Diphtheria Toxin; D000922:Immunotoxins; D007376:Interleukin-2; D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D004247:DNA