| abstract |
Natural suppressor (NS) cells secrete a soluble protein suppressor factor (SF) which suppresses the mixed lymphocyte response. NS cells as described herein are null, i.e., have the phenotype IL-2R?+, CD3-, CD4-, CD8-¿, TCRαβ?-, Ig-, MAC-1-¿, or are double negative suppressors (DNS); i.e., have the phenotype IL-2R?+, CD3+, CD4-, CD8-¿, TCRαβ+. Both NS and SF are useful in vivo to confer immunotolerance with respect to allogeneic transplants, and to effect immunosuppresion. They also enhance engraftment of transplanted cells. A population of cells can be provided using density gradient separation techniques which is enriched in progenitor cells as identified by the presence of CD34 surface markers. |