Lipoprotein (a) and plasminogen are immunochemically related.

This study provides evidence that the antigen specific to lipoprotein (a), a lipoprotein known for its high potential to lead to plaque build-up in arterial walls, shares immunochemical relations with plasminogen, a protein involved in the breakdown of blood clots. This relationship was demonstrated via tests involving antisera and antibodies, and highlighted lipoprotein (a)’s distinct interaction with a substance known as lysine-Sepharose and its impact on fibrinolysis, the process of clot breakdown.

Immunochemical Relationship Between Lipoprotein (a) and Plasminogen

• The main finding of this research is the immunochemical relationship that exists between lipoprotein (a) and plasminogen, two proteins that play significant roles in cardiovascular physiology. Specifically, lipoprotein (a) is an atherogenic lipoprotein, meaning it can contribute to the formation of atherosclerotic plaques in blood vessels, while plasminogen is involved in the dissolution of blood clots in the body.
• These immunochemical relations were shown using antisera (the part of the blood that contains antibodies) obtained from various animals including rabbits, sheep, and horses, as well as monoclonal antibodies (laboratory-produced molecules engineered to attach to specific cells) from mice.

Lipoprotein (a) Interactions and Mechanisms

• Adsorbers specific to lipoprotein (a) were utilized revealing the complete and selective absorption of plasminogen from both lipoprotein (a)-positive and apparently lipoprotein (a)-negative plasma. This underpins the immunochemical relationship between the two entities.
• Besides having an immunochemical relationship with plasminogen, lipoprotein (a) also shares a selective binding trait with plasminogen to a material called lysine-Sepharose. The relationship, however, is not as strong, indicating a lower affinity.

Influence of Lipoprotein (a) on Fibrinolysis

• The study further shows that lipoprotein (a) has a notable effect on fibrinolysis – the body’s process of breaking down blood clots – when challenged with a compound called streptokinase, which is often used in medicine to dissolve blood clots. Under certain experimental conditions, fibrinolysis was significantly prolonged by lipoprotein (a).