*2.9. Adhesion Assay*

The adhesion of *E. histolytica* trophozoites to HeLa cells (a kind gift from T. Kleinberger, Faculty of Medicine, Technion) was measured using a previously described protocol [28]. *E. histolytica* trophozoites (2 × <sup>10</sup>5) were incubated with live *L. acidophilus* (2 × <sup>10</sup>8), with heat-killed *L. acidophilus* (DN) (2 × 108), with paraformaldehyde-fixed *L. acidophilus* (PLA) (2 × <sup>10</sup>8) and with/without catalase (50 <sup>μ</sup>g/mL) for 1 h at 37 ◦C and then transferred to paraformaldehyde-fixed HeLa cells monolayers for an additional hour of incubation at 37 ◦C. Trophozoites unattached to HeLa cell monolayers were washed once with phosphate buffer saline (PBS) buffer and the trophozoites attached to the HeLa cell monolayer were eluted with 500 μL of a solution of cold galactose (1%) in PBS and counted.

#### **3. Results and Discussion**
