Partial overlap of anti-mycobacterial, and anti-Saccharomyces cerevisiae mannan antibodies in Crohn’s disease

Figure 6 ASCA strongly cross-react with mycobacterial antigens in a subgroup of ASCA-positive CD patients. A: Eight sera from highly ASCA-positive CD patients were incubated with membrane sections of yeast mannan Western blots containing the ASCA-reactive material, and bound antibodies were eluted. Eluted antibodies were titrated to yield comparable extinction values in the ASCA ELISA as with the original serum (approx. 100%, empty columns) and used at the corresponding dilution to assess reactivities against mycobacterial antigens. As a specificity control for affinity purification, eluted antibodies were also tested in a tetanus toxoid (TT) ELISA. B: The same 8 patients’ sera were also affinity purified on nitrocellulose membranes decorated with M smegmatis lysate. In analogy to A, eluted antibodies were adjusted for equal reactivity with M smegmatis as the original sera (approx. 100%, empty columns) and tested at the corresponding dilution for reactivities against yeast mannan and TT.