Native ldl did nor form associates during incubation with cultured cells. The relative size of lipopritein particles was one unit. As usually, native ldl did not cause cholesterol accumulation in cultured cells. In cell culture modified ldl formed associates with mean relative size about five units. As a result of incubation of cultured cell with modified ldl intracellular cholesterol was increased three-fold. Filtration of culture medium through filter with pore size four hundred fifty nanometers let to reduction of ldl associate size and to significant decrease of ldl atherogenicity. Filtration through two hundred twenty nanometers caused further reduction of associate size and ldl atherogenicity. And finally, one hundred nanometer pores eliminated ldl associates and prevent cholesterol accumulation completely. You can see very close relationship between ldl associate size and atherogenicity of modified lipoproteins.