MeSH note : factor in supernatant of alloantigen-activated T cells which reversibly binds to IgG,
interfering with IgG complement activation; also suppresses IgA synthesis by T cell
hybridomas; suppresses polyclonal human IgE response; can also enhance IgE synthesis;
also a serine protease; see also record for Mac-2 antigen (IgE-binding protein);