EFFECT OF AMINO-ACID MODIFICATION AND POLYMERIZATION ON THE IMMUNOCHEMICAL REACTIVITY OF COD ALLERGEN-M

The modification of the lysyl, tyrosyl, tryptophyl or arginyl side chains and the release of the two calcium ions, respectively, degraded the immunochemical reactivity of Allergen M. The IgE and IgG mediated activities were similarly diminished as assessed by RAST/RAST-inhibition for the former, and Farr/precipitin tests for the latter. The findings suggested, therefore, that the allergenic and antigenic sites on the Allergen M molecule, if distinct, are structurally homologous. Qualitative degradation of the native tertiary structure of Allergen M following specific chemical modification or removal of Ca2+ only somewhat reduced the immunochemical reactivity, emphasizing the sequential character of the determinants. Polymerization of Allergen M strongly reduced its immunochemical reactivity as well as its immunogenic potential in the rabbit. Carbodiimide cross linking of fragment TM 1 reduced its primary interaction with antibody while enhancing the formation of immune-complexes. In contrast, in all test systems used, cross linking of fragment TM 2 to a trimer polypeptide enhanced both allergenic and antigenic reactivity. © 1979.