Collagen fragments modulate innate immunity.

Activation of the innate immune response in diseases such as rheumatoid arthritis and atherosclerosis leads to the production of proinflammatory cytokines that can promote collagenolysis. While a number of studies suggest that inflammation plays a major role in initiating collagen degradation, the effect of collagen and collagen-degradation fragments on the inflammatory response is not well understood. We now demonstrate that different collagen fragments can either augment or suppress IL-1beta production from human peripheral-blood monocytes. These data have wide-ranging implications for how amino acid variation in collagen affects disease and suggest that collagen degradation leads to the production of peptides that can modulate inflammation.