Erythropoietin-like activity in vivo of the fusion protein rhIL-6/IL-2 (CH925).
CH925 is a novel cytokine of a fusion protein interleukin-6 (IL-6)/IL-2 exhibiting erythropoietin (Epo)-like effects in vivo and ex vivo, in addition to its enhanced effects compared to IL-2 and IL-6 reported by us previously, which indicates its potential clinical use. Our present study was undertaken to determine the Epo-like activity of CH925 in vivo. The reticulocyte response was observed in transfusion-induced polycythemic mice by using flow cytometry with pyronin Y staining. On day 2 after injection of CH925, the average number of reticulocytes was 2.11% in the group given 250 micrograms/kg/d and 1.01% for 100 micrograms/kg/d. The mean fluorescence intensity (MFI) also significantly increased. Longitudinal studies of CH925 were performed on days 2, 4, and 10, and reticulocyte counts increased up to a peak on day 4. Activity of CH925 (100 micrograms/kg/d) corresponds to 1 U of standard rhEpo in our study.
Department of Cell Biology, Sinochem Institute of Biotechnology, Beijing, China.
C
C
Zhao
P
P
Tang
N
N
Mao
S
S
Zhang
E
E
Fan
B
B
Dong
Q
Q
Li
D
D
Du
D000818:Animals; D001483:Base Sequence; D001803:Blood Transfusion; D002455:Cell Division; D015672:Erythroid Precursor Cells / Q000166:cytology; D004921:Erythropoietin / Q000494:pharmacology*; D005260:Female; D005434:Flow Cytometry; D007376:Interleukin-2; D015850:Interleukin-6; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D011086:Polycythemia / Q000097:blood / Q000209:etiology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000494:pharmacology*; D017701:Reticulocyte Count
D007376:Interleukin-2; D015850:Interleukin-6; D011993:Recombinant Fusion Proteins; C089276:recombinant fusion protein IL-6 - IL-2; D004921:Erythropoietin