Figure 4

Interactions of Acvr1b with other proteins in secondary infection. Acvr1b, Smad2 and Smad3 were found to be important in secondary infection. Smad7, an inhibitory SMAD protein, interacted with Acvr1b in secondary but not primary infection. This disparity suggests that TGF-β signaling may play a role in the control of innate and adaptive immune responses.