Membrane receptors for the soluble ‘defense collagens’ — naturally occurring chimeric molecules that contain a recognition domain contiguous with a collagen-like triple helical domain and play a role in protecting the host from pathogens entering the blood, lung and other tissues – are being isolated. These receptors are key to understanding the mechanisms by which defense collagens influence cellular responses in order to either provide rapid ‘stealth clearance’ of cellular debris or to initiate the responses that lead to the destruction of harmful microbes.