[Preparation and bioactivity evaluation of streptavidin-tagged human interleukin-15 fusion protein].
OBJECTIVE
To obtain streptavidin-tagged human interleukin-15 (SA/hIL15) fusion protein and evaluate its bioactivity.


METHODS
pET24a-6His-SA-hIL-15 and pET32a-hIL-15-SA-6His plasmids were constructed and expressed in BL 21(DE3) host bacteria to generate the fusion protein. The recombinant fusion protein IL-15/SA was purified using Ni-NTA affinity chromatography and refolded, and the efficiency of surface modification of the fusion protein on biotinylated cells was examined by fluorescence-activated cell sorting. CCK-8 method was used to evaluate the effect of IL-15/SA fusion protein in inducing the proliferation of human peripheral-blood lymphocyte (PBL) cells stimulated by PHA.


RESULTS
The recombinant SA-hIL-15 and hIL15-SA fusion proteins were highly expressed in BL21(DE3) at about 20% of the total bacterial proteins. The purified hIL15-SA fusion protein exhibited a bifunctionality by promoting the proliferation of PBL cells activated by PHA and high-affinity binding to biotinylated cell surface mediated by SA, with a cell surface modification efficiency exceeding 95%. SA-hIL-15 showed a 4-fold higher hIL15 bioactivity than hIL15-SA.


CONCLUSIONS
SA/hIL-15 bifunctional fusion protein has been successfully obtained to facilitate the future development of hIL-15-surface-modified cancer cell vaccine.
Su
Hua
H
Wenzhou Medical College, Wenzhou, China. suhua_1@163.com
Chen
Yan-Li
YL
Chen
Su-Yun
SY
Wen
Bo
B
Yu
Hong-Sheng
HS
Hu
Zhi-Ming
ZM
Gao
Ji-Min
JM
D019496:Cancer Vaccines / Q000235:genetics / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005822:Genetic Vectors; D006801:Humans; D019409:Interleukin-15 / Q000096:biosynthesis* / Q000235:genetics; D008213:Lymphocyte Activation / Q000187:drug effects*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D019809:Streptavidin / Q000096:biosynthesis* / Q000235:genetics
D019496:Cancer Vaccines; D019409:Interleukin-15; D011993:Recombinant Fusion Proteins; D019809:Streptavidin