Western immunoblots of purified type 3 fimbriae from K. pneumoniae IApc35 transformants. The gels were probed with anti-type 3 fimbria-specific serum to detect the MrkA major subunit, stripped, and subsequently probed with the anti-MrkD1P serum. Lanes 1, 2, and 3 include fimbriae from transformants possessing pTS68, pTS71, and pTS72, respectively, and were overloaded with fimbrial proteins in order to demonstrate the absence of MrkD1P in these samples. Lanes 4 and 5 include fimbriae from pTS76 and pTS78.