The mAb were also tested for their capacity to block the atypical cleavage of C5 by NE, a process that has been implicated in the generation of C5a and MAC at inflammatory sites such as in the rheumatoid joint and cystic fibrosis lung;37, 38, 39 mAb that inhibited this cleavage might therefore have additional value as therapeutics. This evidence concerns the gene C5 and cystic fibrosis.