Objective To inve stigate the function of the αvβ5 integrin in hematopoietic cells1 Met h o ds Tissue culture, integrin expre ssion vectors, gene transfer, polymera se chain reaction ( PCR), apopto sis analyse s and cytometic analysis were made on hematopoietic cells1 Re s ult s Theβ5 integrin cDNA wa s not expre ssed in hematopoietic cells following expo sure to the β5 integrin retrovirus vector p Gβ5CHT1 Unbalanced expre ssion of the αvβ3 and αvβ5 integrins occurred during apopto sis induced by serum depletion and upon differentiation1 The treatment of hematopoietic cells with anti2αvβ5 monoclonal antibody inhibited apopto sis induced by serum depletion1 Inducible expre ssion of the β5 integrin cDNA in the hematopoietic cell line K562 caused cellular proliferation inhibition1 Co nclusion The αvβ5 integrin cDNA in hematopoietic cells can inhibit the proliferation of the hematopoietic cell, cause the differentiation of the hematopoietic cells and induce the apopto sis of the hematopoietic cells.