Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:Indeed, it has been demonstrated that ADAM17 deficiency leads to protection against lethal shock by LPS (53, 54), whereas iRhom2-deficient mice, in which ADAM17 cannot be activated, failed to control the replication of the Gram-positive bacterium Listeria monocytogenes (55).
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