A QUANTITATIVE FOCUS ASSAY FOR TITRATION OF RETROVIRUSES THAT ENCODE HUMAN GRANULOCYTE–MACROPHAGE COLONY-STIMULATING FACTOR (GM-CSF)
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- 作者：Feldman ; Ricardo A.
- 刊名：Cytokine
- 出版年：1999
- 出版时间：June, 1999
- 年：1999
- 卷：11
- 期：6
- 页码：459-462
- 全文大小：176 K
文摘
Granulocyte–macrophage colony-stimulating factor (GM-CSF) is a haematopoietic growth factor that regulates proliferation, differentiation, and effector functions of monocyte-macrophages and granulocytic cells. Because of the ability of this cytokine to enhance immune functions of antigen-presenting cells, retroviruses encoding GM-CSF have been used to transduce GM-CSF into murine and human tumour cells as part of autologous tumour vaccine strategies. We have previously shown that NIH 3T3 cells engineered to express functional human GM-CSF receptors (hGMR-NIH 3T3), become fully transformed when these cells are incubated in the presence but not in the absence of human GM-CSF. In this study we have used these hGM-CSF conditional transformants to devise a sensitive focus assay to titrate retroviruses encoding hGM-CSF, using MFG-hGM-CSF/Ψ-CRIP as our model virus. This helper-free amphotropic retrovirus, which has been frequently used to transduce hGM-CSF into tumour cells, was quite transforming in our indicator cell line, exhibiting virus titres well above 105FFU/ml. The transformation-based assay described here allows rapid determination of the titre of hGM-CSF-viruses, and may serve as a model for development of quantitative assays for other cytokine-encoding viruses of clinical importance.