What is the Difference Between CD55 and CD59?
🆚 Go to Comparative Table 🆚CD55 and CD59 are both glycoproteins that regulate the complement system, but they have distinct functions:
- CD55: This protein accelerates the degradation of C3 and C5 convertases and prevents the formation of new enzymes. It is encoded by the CD55 gene in humans.
- CD59: Also known as membrane inhibitor of reactive lysis (MIRL), CD59 interferes with membrane attack complex (MAC) formation. It is encoded by the CD59 gene in humans.
Both CD55 and CD59 are widely expressed in all circulating cells and most human tissues. They play crucial roles in regulating host immune responses and preventing excessive activation of the complement system, which could lead to damage to the body's own cells. Mutations affecting the GPI anchor can reduce the expression of both CD55 and CD59, resulting in a disease called paroxysmal nocturnal hemoglobinuria (PNH).
In summary, the main difference between CD55 and CD59 is their specific role in regulating the complement system: CD55 inhibits the aggregation of C3 and C5 convertases, while CD59 prevents the polymerization of C9 and the formation of membrane attack complexes.
Comparative Table: CD55 vs CD59
CD55 and CD59 are two proteins that regulate the complement system by inhibiting the formation of complement membrane attack complexes. They are both glycoproteins, and mutations affecting the GPI anchor can reduce their expression, leading to diseases like paroxysmal nocturnal hemoglobinuria. However, there are some differences between these two proteins:
| Feature | CD55 | CD59 |
|---|---|---|
| Function | Inhibits aggregation of C3 convertases of the classical complement pathway | Prevents C9 from polymerizing and forming a complement membrane attack complex |
| Gene | Encoded by the CD55 gene in humans | Encoded by the CD59 gene in humans |
A study investigating the expression of CD55 and CD59 on red blood cells in patients with anemia of chronic kidney disease found altered expression patterns for both proteins, which could play a role in the pathogenesis of anemia in these patients. Another study suggested that there is a preferential loss of CD59 expression, but not CD55 expression, on red blood cells during blood storage.