Table 2.

Hematologic responses to 3 different conditional signaling proteins

Response	F36VFGFR1	F36VMpl	V′ VJak2
In vitro
Sustained expansion in culture	+	+	-
Expansion of stHSCs	+	-	ND
Survival of ltHSCs	+	-	ND
In vivo
Red cells	+++	++	+
Platelets	+++	+	-
Granulocytes/monocytes	+++	+/-	-

+ indicates present; -, absent; ND, not done; +++, strongest effect; ++, strong effect; +/-, variable and modest effect.