TRANSDUCTION EFFICIENCY OF CELL-LINES AND HEMATOPOIETIC STEM-CELLS CORRELATES WITH RETROVIRUS RECEPTOR MESSENGER-RNA LEVELS

The low transduction efficiency of hematopoietic stem cells (HSC) usin g amphotropic retroviruses continues to plague gene therapy protocols. This low transduction efficiency may be related to a low level of amp hotropic retrovirus binding to target cell receptors. We have assayed murine and human cell lines as well as primary bone marrow HSC populat ions for mRNA encoding retrovirus receptors. Total cellular RNA was am plified by reverse transcriptase-polymerase chain reaction and the lev el of ecotropic and amphotropic receptor mRNA was compared to the leve l of beta 2-microglobulin mRNA in the same cell populations. Cell line s that are easily transduced by ecotropic and amphotropic retroviruses have high levels of receptor mRNA. In studies using murine HSC-enrich ed populations obtained from bone marrow, we observed a high correlati on between transduction efficiency and the level of ecotropic and amph otropic receptor mRNA. We predict from these findings that purificatio n of monkey and human HSC populations with high levels of amphotropic receptor mRNA will enable us to obtain improved efficiency of gene tra nsfer.