LCN2 and infection: A function of lipocalin-2 in the innate immune defense against bacteria was demonstrated shortly after the discovery of lipocalin-2 as a siderophore-binding protein [7], [18], [19], as mice deficient in lipocalin-2 are more susceptible to infections by E. coli[20]–[22], K. pneumonia[23], and M. tuberculosis[24], [25] than their wild-type litter controls.