Analysis of pro and mature SP-B and SP-C in BALF. Patient A (Pt A). Molecular weights (MW, kDa) are indicated on the left side. 5 μg of total protein was added to each lane from lavage of a patient. All bands were analyzed under non-reducing conditions. A small amount of pro-SP-B was detected at 21 kDa in Pt A (second lane from left). As positive control pro-SP-B of a lavage from a healthy subject (Con, nl) is given (first lane from the left). SP-B was detected in fair amounts (third lane compared to the standard (STD) of which 20 ng was applied). Aberrant proforms of SP-C were not detected (third lane from the right). As positive control pro-SP-C of a lavage from a subject with SFTPC mutation I73T, which usually have aberrant pro-SP-C at about 14 kDa (Con, I73T) is given (fourth lane from the right). No SP-C was detected (second lane from the right; compared to the standard STD of 25 ng applied to the first lane from the right).