CTLA4 and infection: Additionally, during several infections the expression of inhibitory molecules and E3 Ubiquitin ligases has been previously shown to be upregulated and to induce T cell hyporesponsiveness [51,52], with blocking CTLA-4 or neutralizing TGF-β during lymphatic filariasis restoring the ability to mount Th1/Th2 responses to live parasites and reversing the induction of anergy-inducing factors [51].