Macrophages were incubated with apolipoprotein B-containing lipoproteins, the complexes of lipoprotein with dextran sulfate (DS) or antibodies (lipoprotein cholesterol 200 mg·L~(-1), dextran sulfate 0.4 mg or antibodies 0.1 ml) for 24 h. The cholesteryl esters (CE) in macrophages were determined by thinlayer chromatography. The results that native lipoprotein (a) did not give rise to any significant storage of intracellular cholesteryl esters (0. 9 mg·g~(-1) cell protein,p>0. 05); low density lipoprotein (LDL)increased CE formation in macrophages ( 4.0 mg·g~(-1) cell protein, p<0. 05); lipoprotein (a)-DS or LDL-DS complexes caused a significant enhance in CE formation in macrophages, which were 7. 7 ,and 8. 7 mg·g~(-1) cell protein ,respectively (P < 0. 01 ); similar result were observed when macrophages were incubated with both the complexes of lipoprotein (a) with antibodies against apolipoprotein (a) or apolipoprotein B and LDL with antibodies against apolipoprotein B,which were 19.9, 18.3 and 17. 4 mg·g~(-1) cell protein, respectively (p<0. 01 ) . The above data showed that the complexes of apolipoprotein B-containing lipoproteins with DS or antibodies could cause lipid accumulation in macrophages.