Development of an enzyme-linked immunosorbent assay, using a monoclonal antibody against alpha(2)-macroglobulin, for the diagnosis of systemic lupus erythematosus

Objectives: To develop an enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody (mab) directed against abnormally glycosylated serum a lpha(2)-macroglobulin (alpha(2)-M) from patients with systemic lupus erythe matosus (SLE). Design and methods: Serum alpha(2)-M purified by HPLC from patients with SL E was injected in a Balb/c, CB6 F1 female mouse and hybrid cell lines were screened using alpha(2)-M Glu-C fragments derived from SLE and normal donor s (NHS). A mab was selected and used to develop an ELISA by which sera from NHS (n = 14), SLE (n = 34), rheumatoid arthritis (n = 15), Sjogren's syndr ome (n = 11), mixed connective tissue diseases(n = 12), and liver diseases (n = 11) were analyzed. Results: The affinity of the mab for alpha(2)-M from SLE, but not from the other diseases, was higher compared to NHS, as demonstrated by immunoblotti ng and ELISA, Conclusions: The ELISA was capable of recognizing changes of glycosylation of alpha(2)-M in SLE and may be useful for its differential diagnosis. Copy right (C) 1999 The Canadian Society of Clinical Chemists.