The role of autologous helper and suppressor T cells in the regulation of human granulopoiesis

Helper and suppressor T cells play a physiological role in immunoregulation and possibly in other biological systems. Previous studies have suggested that unfractionated T cells influence human blood cell formation in vitro. Subpopulations of such cells (T M and T G cells) were prepared by immune ox erythrocyte resetting techniques. Co‐cultures were established in semi‐solid agar with autologous null lymphocytes as a source of granulocyte—macrophage progenitor cells (CFU‐GM). T M (helper) cells produced an increase and T G (suppressor) cells a decrease in the expression of CFU‐GM as reflected in the number of GM colonies generated by comparison with cultures of null lymphocytes alone. These data point to a contribution from T lymphocyte subpopulations to the physiological regulation of human granulopoiesis.