[Effects of FPIL6/IL2 on the differentiation and proliferation of lymphoid in the ML-IC assay].
OBJECTIVE
To develop an in vitro assay that allows the culture and identification of a single human bone marrow progenitor closely related to hematopoietic stem cell, which is more primitive than LTC-IC, and to find an efficient culture conditions for NK-IC expansion.


METHODS
Fusion protein IL6/IL2 was reconstructed and expressed in E. coli DH5 alpha. ML-IC was determined by watching if the single cell can give rise to secondary progenitors with both LTC-IC and NK-IC characteristics. LTC-IC frequency was determined by the CFC clonogenic methylcellulose assay. NK-IC frequency was determined by phenotyping CD56 positive NK cells. The effect of FPIL6/IL2 on the expansion of NK-IC was examined by comparing the colony number of NK cells before and after the culture.


RESULTS
After the initial 4-week expansion culture, we showed that (25.75 +/- 5.68)% of freshly sorted Lin-/34+/DRdim cells were able to generate functional NK-IC in one or more secondary FPIL6/IL2 cultures, whereas (6.81 +/- 1.97)% in the control. A total of 102 NK-IC cells were present when were cultured for 6-7 weeks in FPIL6/IL2 expansion medium, which was much higher than the 33 NK-IC cells in the control.


CONCLUSIONS
ML-IC assay will prove useful to assess a very primitive hematopoietic cell with multilineage generative capacity. FPIL6/IL2 is capable of initiating and promoting NK-IC expansion greatly in ex vivo cultures in terms of net-conservation and net proliferation.
Fan
Er-jin
EJ
State Key Lab of Experimental Hematology, Institute of Hematology, CAMS, PUMC, Tianjin 300020, China.
Song
Jun-min
JM
Xu
Shi-rong
SR
Zhao
Chun-hua
CH
D000818:Animals; D001681:Biological Assay; D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D018920:Coculture Techniques / Q000379:methods; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis / Q000235:genetics* / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics* / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D017154:Stromal Cells / Q000166:cytology
D007376:Interleukin-2; D015850:Interleukin-6; D011993:Recombinant Fusion Proteins