Carcinoembryonic antigen (CEA)-related cell adhesion molecules are co-expressed in the human lung and their expression can be modulated in bronchial epithelial cells by non-typable Haemophilus influenzae, Moraxella catarrhalis, TLR3, and type I and II interferons

Klaile, Esther; Klassert, Tilman E; Scheffrahn, Inka; Müller, Mario M; Heinrich, Annina; Heyl, Kerstin A; Dienemann, Hendrik; Grünewald, Christiane; Bals, Robert; Singer, Bernhard B; Slevogt, Hortense

BALF samples with at an average concentration of 93 ng/ ml (± 48 ng/ml SD). In order to approach soluble CEACAM1 expression in human lung with an alternative method, normal human bronchial epithelial (NHBE) cells from healthy donors were used for transcription analysis. RT-PCR and subsequent sequencing of the obtained PCRproducts confirmed the expression of three soluble CEACAM1 isoforms, CEACAM1-4C1, CEACAM1-3 and CEACAM1-3C2 ( Figure 2B ). However, mRNAs of all three isoforms were not expressed at sufficient levels to allow for reliable quantification analysis by qPCR. To test for expressed and shedded soluble CEACAMs in NHBE cells, CEACAM1-, 5-, and 6-immunoprecipitations from cell culture supernatants were analyzed. Western blot analysis revealed soluble CEACAM6 and low amounts of soluble CEACAM1, but no soluble CEACAM5 ( Figure 2C ) in NHBE cell culture supernatants.