The induction and possible subsequent effect of human antibodies against porcine enamel matrix derivative

Background: The amino acid sequence of porcine amelogenin, the major component of enamel matrix derivative (EMD), is ∼91% identical to that of its human counterpart. Whether porcine EMD (pEMD) can elicit neutralizing antibodies after the first surgery, thereby reducing the clinical effect of secondary surgery, has not been established. Methods: The sera of patients receiving periodontal surgery with or without pEMD were collected before and after surgery. The pEMD product was subjected to electrophoresis and transferred for a Western blot using the purified antibodies from patients as the primary antibodies. To clarify whether the antibodies in patients could inhibit the production of transforming growth factor-β1 (TGF-β1), we added different amounts of purified antibodies from pEMD patients (before versus after surgery) into the cell cultures of periodontal ligament fibroblasts. The conditioned media were then collected for an immunoassay of TGF-β1. Results: The result of the Western blot demonstrated that human antibodies against pEMD were elicited 10 days after surgery. Using mass spectrometry, a non-specific band on the Western blot appeared to be porcine immunoglobulin G (IgG). The results of the immunoassay showed the antibodies from pEMD-treated patients did not hinder the subsequent production of TGF-β1. Conclusions: The pEMD product was contaminated with porcine IgG. The application of the product could induce antibodies against different isoforms of porcine amelogenin in humans. However, the increased antibodies did not hinder theproduction of TGF-β1, one of the established in vitro functions of pEMD on periodontal ligament fibroblasts.