Study at the Harvard Medical School: Effect of gold on antigen-presenting cells

In this study performed by a group around Prof. Dr. Brian DeDecker at the Harvard Medical School with an amount of 110,000 USD and published in the renowned professional journal Nature Chemical Biology it has been proven that noble metals such as gold have a modulating effect on class II MHC proteins. These proteins “are essential for the normal function of the immune system but also drive many autoimmune responses”, among which are rheumatic diseases. “They bind peptide antigens in endosomes and present them on the cell surface for recognition by CD4+ T [helper] cells.” “This previously unknown allosteric mechanism may help resolve how gold(I) drugs affect the progress of rheumatoid arthritis and may provide a basis for developing a new class of anti-autoimmune drugs.”

In total about 28,000 (!) compounds and natural extracts have been investigated. Of these, only four exhibited an effect on class II MHC proteins: two platinum, one palladium and one gold salt compound, KAuIIICl4. By means of an allosteric mechanism, they strip peptides from human class II MHC proteins and block the ability of antigen-presenting cells to activate T cells. The authors regret in the article that they did not find a way for their in-vitro experiment to investigate pure metal complexes. However, in a second step they investigated the in-vitro effect of gold and platinum complexes in living human lymphoid cells. “Both metals showed significant inhibitory activity [upon antigen-presenting cells] at concentrations that have been shown to be present in patients.”

Comment by Team Ackermann:

Even if treatment with gold salts cannot be equated directly with gold implantation due to their severe side effects, the study nevertheless proves the fundamental effect of gold on inflammatory processes.

Link to the study: http://www.nature.com/nchembio/journal/v2/n4/full/nchembio773.html