Ref ID : 4870
I. Finger, A. Lynn, and M. Bernstein; Identification of Regulators of Paramecium Surface Antigen Expression and of Regulator-Antigen Complexes. Arch.Protistenk 146:207-218, 1995
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Individual paramecia are capable of making about a dozen surface antigens (i antigens) but usually express only one at a time. A model for this mutual exclusion has suggested that antigen binds to an antigen-specific inhibitor acting at the transcription level, thus controlling its own synthesis. We have shown that a group of proteins of about 70 kD molecular weight present in conditioned media and in partially purified antigen preparations may act as the proposed inhibitors. These putative inhibitors can be identified in vitro through enzyme-linked immunosorbent assays. Antibodies against the 70 kD molecules can be recognized by the immobilization of cells exposed to antisera when secondary antibody against rabbit immunoglobulins is applied sequentially. In addition, immunoprecipitates of surface antigens have been analyzed by gel diffusion using antisera having antibodies against both surface antigens and "inhibitors". From these diverse approaches, we conclude that the "inhibitors" are probably surface bound and that they form complexes with specific surface antigens.