The effects of the induction of differentiation were investigated on the expression of heat shock proteins (hsps) and thermotolerance. The synthesis of the major hsps in response to heat stress was markedly enhanced in HL-60 human leukemia cells after differentiation. An increased amount of mRNA transcripts for hsp70 was also noted. In addition, induction of differentiation resulted in acquisition of greater resistance to heat, which may be advantageous since cells in the peripheral blood must survive many stresses.
