CONFORMATIONAL-CHANGES IN PH2-TREATED HUMAN INTERFERON-ALPHA-2 DETECTED WITH MONOCLONAL-ANTIBODIES

Monoclonal antibodies allowed to demonstrate the existence of alternat ive antigenic forms of the same molecule as of human interferon (IFN)- alpha 2. Exposure of recombinant IFN to pH 2, although not affecting i ts bioactivity, induced structural modulation of molecular surface, Th e antigenic structure of IFN-alpha 2 appeared to be built of the acid- stable and acid-labile epitopes, In general, the acid-stable sites det ermined subtype-specific antigenic properties of the protein, whereas the acid-labile determinants were responsible for antigenic characteri stics shared by some other human IFNs. Acidification of IFN-alpha 2 to on 2 for at least 1-2 h resulted in simultaneous structural rearrange ment of all acid-labile sites.