Electroimmunoassay of human serum lipoproteins containing Apo A-I by monoclonal antibodies.

Three monoclonal antibodies to human serum apolipoprotein (Apo) A-I (4A12, 4B11 and 2G11) were produced by Sanofi. They were directed to three distinct epitopes of the Apo A-I molecule, present on the surface of the lipoprotein particles. They were able to precipitate individually some lipoprotein units from the serum. Only the mixture of the three monoclonal antibodies could allow a precipitation of all Apo A-I containing particles. An electroimmunoassay using this oligoclonal mixture was assessed to standardize the Apo A-I measurement in serum. Results agreed well with those obtained by electroimmunoassays using polyclonal antisera. Moreover no pretreatment of serum samples with dissociating agents or detergents was required. Therefore, this specific, rapid (7-8 h), precise (within- and between-assay precisions were 4.25 and 3.1%, respectively) immunoassay is routinely available for apolipoprotein A-I measurement in serum.