Fig. (4) SasG, α-haemolysin and SplB are major immunodominant components of S. aureus liquid culture.Panel A. Immunoreactivity of SasG domains A, B and C. Purified MBP-tagged fragments of SasG (SasG-A, -B and -C) were assayed in SDS-PAGE with silver staining and Western blot with non-immune mouse serum, with mouse serum directed against absorbed staphylococcal anatoxin and with commercial monoclonal and-MBP antibodies. A plus-sign denotes non-specific band in SasG-B preparation reacted with the non-immune serum. Molecular mass markers are shown on the right. Asterisks on the right in SDS-PAGE section denote positions of the expected full-size products of the corresponding cloned genes.Panel B. Immunoreactivity of staphylococcal products with mouse and rabbit sera. Staphylococcal anatoxin and the purified recombinant proteins were tested in Western blot with the non-immune (- immunization) and absorbed staphylococcal anatoxin immunized (+ immunization) mouse (left panel) or rabbit (right panel) sera. Typical ladder-like appearance of SasG due to its cleavage/homo-oligomerization [26, 29, 47] is seen. Please note higher molecular mass of recombinant SplB in comparison to the wild type variant in the staphylococcal anatoxin sample because of the engineered 6xHis-containing peptide in the former protein.