Changes in concanavalin A-reactive proteins in inflammatory disorders.

Quantitative changes of concanavalin A (Con A)-reactive proteins in serum samples obtained from rats with induced inflammation and from patients with inflammatory and autoimmune diseases were examined by use of lectin blots. Treatment of rats with a single dose of fermented yeast to induce inflammation caused an extensive increase in Con A-reactivity. These changes were time dependent and were similar in both sexes of the animals. When we examined serum samples obtained from patients with various inflammatory disorders for their Con A-reactive proteins as compared with normal donors, we noted that the Con A-reactivity increased in patients with rheumatoid arthritis and systemic lupus erythematosus. Among all the glycoproteins examined by lectin blots with use of Con A, a set of five proteins was selected for detailed analysis by densitometric scanning. These included alpha 2-macroglobulin, P-150, P-95, P-40, and P-35, of Mr 180,000, 150,000, 95,000, 40,000, and 35,000, respectively, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. Densitometric scanning analysis of the lectin blots revealed that the Con A-reactivity of these proteins increased during inflammation. Because alpha 2-macroglobulin is not an acute-phase protein in humans, an increase in Con A staining of this protein suggested that altered glycation is associated with autoimmune diseases. Thus, study of changes in Con A-reactive proteins in human sera may facilitate our understanding of the etiology and pathophysiology of autoimmune diseases