My dissertation focuses on the effect of pH variations on the activity of two ion channels. In the first part, I demonstrate the presence of the pH-sensitive proton channel Hv1 in MDSC (myeloid-derived suppressor cells) using various biophysical, pharmacological, and imaging methods. In the second part, I investigate the effect of pH variations on KCa3.1 and its activators Riluzole and SKA-31, showing tha KCa3.1 is not immediately affected by pH, but its modulators are. In particular, I demonstrated that the intracellular acidification will impair the functionality of Riluzole and SKA-31.