ADRB1 and familial dilated cardiomyopathy: Moreover, using the immunofluorescence and radioligand-binding techniques, we could demonstrate that β1-AA isolated from DCM patients recognized β1-ARs expressed either on CD3+T cells or on H9c2 rat cardiomyoblast cells transiently transfected with β1-AR (Fig. S1C, Fig. 2), whereas after β2-ARs expressed on CD3+T cells were blocked by the specific β2-AR antagonist ICI118551, CD3+T cells can still be stained (Fig. S1B).