**2.1.3 Cell host invasion and intracellular survival by** *Trypanosoma cruzi*

Once *T. cruzi* reaches blood torrent, it invades a great variety of cells in the host. When parasiting non phagocytic cells, *T. cruzi* uses some surface glycoproteins to attach to cell: gp82, gp30 and gp35/50. All three glycoproteins are known to induce calcium mobilization from intracellular reservoirs. Gp82 is linked to the phospholipase C (PLC) and inositol 1,4,5 – triphosphate (IP3). Gp 35/50 is associated to increasing intracellular levels of cyclic AMP. On the other side, cruzipain, a protein known to be secreted by *T. cruzi*, acts on kininogen and produces bradykinin, which binds to its receptor, further increasing intracellular calcium. Increased intracellular calcium produces modifications in cytoskeleton that lead to parasite endocytosis (Yoshida & Cortez, 2008).

In the parasitoforous vacuole, mainly by the action of gp85/TS a glycoprotein with transsialidase action, and TcTox, a protease, the parasite degrades the membrane of the vacuole, escapes from it and proliferates within the cell (Alves & Colli, 2007).
