Figure 5. Serum allo-antibody measurement in grafted animals. Bar diagram: Summary of allo-antibody screening in transplanted animals using a FACS based direct detection method. The presence of IgG1 infers a Th2 response, while the presence of IgG2a antibodies indicates a Th1-IFN-γ induced class switch in B-cells. For IgM detection IgM+ B-cell were excluded from analysis by CD45RA staining (see Figure 2B); IgA isotypes could not be detected. FACS plots: Display of the measurement method for direct binding of allo-antibodies to allogeneic target cells (PVG donor splenocytes); negative controls: serum from PBS injected animals harvested after day 14, positive controls: serum from animals injected with 1×10⁶ γ-irradiated thymic dendritic cells collected after day 14.