NONSPECIFIC-BINDING OF IMMUNOGLOBULINS TO SILICONE IMPLANT MATERIALS - THE LACK OF A DETECTABLE SILICONE SPECIFIC ANTIBODY

Recent studies have suggested that anti-silicone antibodies develop in patients implanted with silicone materials. The majority of these stu dies have utilized enzyme-linked immunosorbent assay(ELISA) methodolog y with a silicons material substrate as a means to detect the presence of the anti-silicons antibody. The current studies were undertaken to determine whether the binding of IgG to a silicons substrate was cons istent with an antigen-specific antibody interaction or the result of non-specific hydrophobic interactions. While significant differences w ere detected in serum from silicons antibody ''positive'' and ''negati ve'' patients when the ELISA was conducted using a phosphate buffered saline (PBS)-0.05% Tween 20 (Tween) blocking system, the difference in the responses was attenuated when protein blocking systems were used or when incubation times were decreased. Furthermore, ELISA studies, u sing purified mouse and human IgG, demonstrated a concentration-depend ent binding of IgG to silicone elastomer substrate which was also atte nuated when a protein blocking system was used in lieu of Tween. In co ntrolled animals studies in which female B6C3F1 mice were implanted wi th silicone gel or silicone elastomer for 180 days, no difference was observed between the implanted animals and the PBS control animals wit h respect to binding of IgG to the silicons substrate. Similar studies in female Fischer 344 rats implanted with silicone gel for 84 days al so failed to demonstrate the presence of anti-silicone antibody. Colle ctively, the results suggest that the binding of IgG to silicone impla nt materials is non-specific in nature, consistent with the well-recog nized interactions between hydrophobic molecules (IgGs) and hydrophobi c surfaces (silicones) in an aqueous-based system.