Ro/SS-A (52 kDa)

Cat. No.Available inproduct_image_10
127000.1 mg
127011.0 mg
 


Diseases:
Systemic Lupus Erythematosus (SLE)
Sjøgren Syndrome, Subacute Cutaneous LE

The Ro/SS-A antigen is a ribonucleoprotein complex and consists of two major proteins of 52 and 60 kDa, complexed with one specific RNA chain (either hY1, hY2, hY3 or hY5, which all are transcripts of RNA polymerase III); the Ro/SS-A (60 kDa) protein is the RNA-binding protein in the complex. The cellular function of this complex is still unresolved, as is the question whether the antigen is primarily located in the cytoplasm or in the nucleus or even shuttles between the 2 compartments. The Ro complex has recently been implicated in small RNA quality control and the enhancement of cell survival following exposure to ultraviolet irradiation.

Ro/SS-A antibodies occur with a prevalence of 60-90% in Sjøgren syndrome patients, but also with a prevalence of 25-50% in SLE patients and higher prevalences in subacute cutaneous LE patients. Neonatal lupus syndrome (congenital heart block, photosensitivity, skin lesions) is also associated with the presence of Ro/SS-A autoantibodies in the maternal and neonatal sera, in particular when these autoantibodies are directed to the 52-kDa antigen. There is a high risk of neonatal lupus if the mother is positive for Ro/SS-A (52 kDa) and La/SS-B antibodies. It should be noted that preparation of native Ro complexes from natural sources often contain substoichiometric and variable amounts of Ro/SS-A (52 kDa) protein, which complicates the detection of autoantibodies against the 52 kDa antigen and points to the usefulness of the recombinant Ro/SS-A (52 kDa) antigen.

Ro/SS-A (52 kDa) protein from DIARECT is expressed in the baculovirus expression system. Ro/SS-A (60 kDa), the other protein subunit of the complex, has recently become available in DIARECT's antigen panel as recombinant human antigen as well as highly purified natural antigen isolated from calf thymus.