FIGURE 3.

Myeloid specific Cftr KO and KI and response to chronic infection. (A) Schematic of the Cftr ^fl10 or Cftr ^invfl10 alleles with and without Cre recombinase present. Primers P1-P4 were used to detect the different alleles (specifics in the methods section). The Cftr ^fl10 conversion to the KO allele is a one way reaction whereas the Cftr ^invfl10 conversion to the KI allele is bidirectional. (B) DNA amplification of the region surrounding exon 10 from various tissues of mice homozygous for Cftr ^fl10 or Cftr ^invfl10 with and without LysMCre. Mice carrying the Cftr ^fl10 allele display no deletion of exon 10 (408 bp) but with LysMCre display at least some of the deleted product KI (148 bp) in bone marrow derived macrophages (M), bone marrow (BM), BAL cells (B), lung (Lu), kidney (Ki) and Liver (Li). Mice carrying the Cftr ^invfll10 allele display the inverted exon 10 (563 bp) but with LysMCre display inversion of at least some of the KI allele (408 b+p) (C,D) Mice were infected with P. aeruginosa and followed for 10 days. Myeloid specific KI (n = 6) and KO (n = 6) models were compared with the WT control (n = 5) mice and each other for BAL neutrophil numbers (C) and P. aeruginosa CFUs (D). The KO had significantly elevated neutrophils (p ≤ 0.05) and more bacteria (p ≤ 0.05) in the BAL than the WT control, whereas the KI model had comparable levels of neutrophils and bacteria. The KI levels of neutrophils and CFUs were significantly less than the KO model (p ≤ 0.05).