IL6 and colitis: At this point of understanding, it would be reasonable to breed double-deficient mice, which express neither IL-6 nor IL-6R (Il-6−/−/Il-6r−/−), and challenge them in comparison with Il-6−/−/Il-6r+/+, Il-6+/+/Il-6r−/− and Il-6+/+/Il-6r+/+ mice in a model of DSS-induced colitis.