SSB (Phospho-Ser366)Colorimetric Cell-Based ELISA Kit

A colorimetric cell-based ELISA kit from Assay Genie is designed for the accurate detection of phosphorylated SSB (Phospho-Ser366) levels in cell lysates and tissue samples, with reactivity for human samples. The assay is intended for adherent cells and offers high sensitivity and specificity. Phosphorylated SSB (Phospho-Ser366) is described as a critical protein involved in DNA repair and maintenance, supporting genomic stability, and its dysregulation has been linked to cancer, genetic disorders, and autoimmune conditions. The NCBI summary notes that autoantibodies reacting with this protein are found in the sera of patients with Sjögren syndrome and systemic lupus erythematosus, making the kit a relevant tool for research into these conditions and potential therapeutic interventions.

The kit is a convenient, lysate-free, high-throughput assay that uses an indirect ELISA format. Phosphorylated SSB (Phospho-Ser366) is captured by target-specific primary antibodies, while HRP-conjugated secondary antibodies catalyze a colorimetric reaction read at 450 nm. The stated dynamic range is greater than 5000 cells. A monoclonal antibody specific for human GAPDH is included as an internal positive control for normalizing target absorbance values, and a Crystal Violet whole-cell staining method is provided to determine cell density so that plating differences can be adjusted.

SSB, also known as Lupus La protein, La autoantigen, La ribonucleoprotein, and Sjögren syndrome type B antigen (SS-B), is a nuclear protein encoded by Gene ID 6741 (UniProt ID P05455) with a molecular weight of 46,837 Da. According to UniProt, it plays a role in RNA polymerase III transcription, binding to the 3' termini of nascent polymerase III transcripts and associating with precursor forms of tRNA and 4.5S, 5s, 7s, and 7-2 RNAs. The kit is supplied in a microplate format and uses a Cell-Based ELISA workflow including fixation, quenching, blocking, overnight primary antibody incubation, secondary antibody incubation, substrate addition, and OD measurement.