[Expression of IL-2 receptors on the surfaces of L1210 cells and bioactivity assay for IL-2-toxin fusion proteins].
OBJECTIVE
To confirm that L1210 cells surfaces express IL-2 receptors (IL-2R) and to establish experimental models for studying the cytotoxic effect of IL-2-toxin fusion protein in vivo and in vitro.


METHODS
IL-2R on mouse leukemia L1210 cells was analyzed with immunofluorescence stain and FACS. The cytotoxic effects in vitro of these fusion proteins IL-2-PEZNM and IL-2-K-PEZNM were assayed by MTT method; mice ascitic L1210 leukemia was induced by i.p. L1210 cells and the therapeutic effect of IL-2-K-PEZNM was observed.


RESULTS
86.3% of L1210 cells expressed IL-2R on their surfaces and the relative fluorescence intensity was 51.55. Two fusion proteins IL-2-PEZNM and IL-2-K-PEZNM showed dose-related cytotoxicities to L1210 cells in vitro with the IC50 of 0.51 and 0.67 microgram/ml respectively. IL-2-K-PEZNM (5 micrograms/d) showed significantly inhibitory effect on L1210 cells and prolonged the survival time of mice by 78.6%.


CONCLUSIONS
L1210 cells as a model system to measure the cytotoxic activity of IL-2-toxin fusion proteins both in vitro and in vivo is simpler, stabler, and safer model than those with other cells such as Hut102 and activated T lymphocytes.
Zhang
L
L
Department of Pharmacology, Institute of Medicinal Biotechnology, CAMS, PUMC, Beijing 100050, China. zhanglili@netease.com
Nie
L
L
Li
H
H
Li
S
S
Lu
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D000818:Animals; D007376:Interleukin-2 / Q000494:pharmacology*; D007939:Leukemia L1210 / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000494:pharmacology*; D014118:Toxins, Biological / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D011993:Recombinant Fusion Proteins; D014118:Toxins, Biological