Resistance and tolerance: two sides of the same coin

Interleukin 1 alpha (IL-1α) and Interleukin 1 beta (IL-1β) are signaling molecules that regulate inflammation and immunity in response to infection. They bind to the same receptor and were previously thought to be redundant. In a new study published in Science Advances, the lab of Pavel Kovarik has discovered that IL-1α and IL-1β exhibit tissue-specific expression patterns and have distinct functions in the defense against bacterial infections. Whereas IL-1β drives bacterial clearance and hence resistance, IL-1α is essential for host defense by promoting tolerance to infections.