Wheat gliadin fractions and other cereal antigens reactive with antibodies in the sera of coeliac patients.
The mixed reverse solid phase passive antiglobulin haemadsorption test (MRSPAH) and the enzyme linked immunosorbant assay (ELISA) were found equally sensitive and fitted for the measurement of serum IgG antibodies against alcohol soluble gliadins. Using the ELISA method, three coeliac sera with elevated antibody titres against gliadins and two control sera with low titres were tested for IgG antibodies against the main groups of wheat proteins (acetic acid soluble glutenins, salt soluble albumins and globulins and alcohol soluble gliadins), eight fractions of gliadin and the alcohol soluble proteins of barley, rye, oat, maize and rice. As rice contained little alcohol soluble protein, a test against acid soluble rice proteins was included. In all three patient sera, titres higher than or equal to that for crude gliadin were found for wheat glutenin and for gliadin fractions seven and eight, both containing alpha gliadins. Similar high titres were found when these coeliac sera were tested against rye, barley and oat prolamines. Maize prolamines gave only low titres and no antibodies could be detected against rice proteins, in line with the tolerance of these latter two cereals by patients with coeliac disease. It would appear that sera from coeliac patients react with more than one antigenic fraction of protein in wheat and other cereals. Also sera from two normal persons appeared to have the same spectrum of reactivity against these cereal proteins as did the three sera from coeliac patients. The titres in normal sera were however much lower.