Etablierung eines Nachweises direkter antibakterieller Wirkung humaner Defensine für die Untersuchung der Defensinproduktion im menschlichen Darm bei Patienten mit Morbus Crohn und Colitis Ulcerosa

As a part of the innate immunity, defensins support the preservation of the intestinal mucosal barrier which is affected in IBD patients. It is interesting whether a potential direct antibacterial activity of defensins in the bowel of IBD patients is changed compared to healthy persons. Since the mechanisms of defensin action are not fully understood, defensins themselves are the only reliable controls in respective studies. Using highly purified recombinant tagged human β2-defensin (hBD-2), a densitometric method for the detection of direct antibacterial activity was established. Although the fusion to glutathion-S-transferase did not affect the reduction of bacterial growth by hBD-2, its bioactivity was lost after altering the storage buffer conditions. This loss, possibly due to protein aggregation, might also occur in defensins extracted from human intestinal specimens and thus substantially impact the determination of their direct antibacterial activities.