Ro/SS-A (60 kDa; recombinant)

Cat. No.	Available in
17400	0,1 mg
17401	1 mg

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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.

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.

Traditional preparations of natural Ro/SS-A (60 kDa) protein purified from calf thymus have the common problem of high lot-to-lot-variation and inconsistent antigen quality. Previous recombinant approaches have failed to provide an antigenically reactive recombinant Ro/SS-A (60 kDa). Development work at DIARECT has opened the way to a recombinant human Ro/SS-A (60 kDa) antigen with full antigenic reactivity, as shown by comparisons to calf thymus-derived protein. Recombinant human Ro/SS-A (60 kDa) from DIARECT is expressed in E.coli.

The companion protein Ro/SS-A (52 kDa) is also available from DIARECT as a recombinant antigen.