This dissertation comprises different aspects of acute and chronic bacterial infection of the lung with special interest in innate immunity and the role of antimicrobial peptides.
In the in vitro part, the influence of the antimicrobial peptides LL-37 and CRAMP on the activation of different immune cells isolated from mouse and human by TLR ligands were analyzed. It was found that LL-37 and CRAMP inhibit the activation of macrophages, neutrophils and dendritic cells by TLR2, 4 and 5 ligands. In addition, CRAMP knockout mice were analyzed in a pulmonary infection model with Pseudomonas aeruginosa. By comparing different parameters of inflammation between KO and WT mice, it was found that CRAMP KO mice possess a surprising advantage in combating a bacterial infection of the lung. The results show that CRAMP, known as antimicrobial peptide, also functions as a negative regulator of inflammation.
