Fig. 3

Inhibition of autophagy by HCQ and CQ triggers apoptosis: Autophagy is often utilized by cells as a survival mechanism to prevent apoptosis. Normal autophagy process includes the fusion of autophagosomes with the lysosome, followed by the degradation and recycling of the internal components like damaged organelles. Accumulation of HCQ and CQ increases the pH inside the lysosomes and prevents the normal autophagy process. This prevention of autophagy triggers apoptosis in memory T-cells and this is one of the fundamental mechanisms of immunomodulation by HCQ and CQ. Also, not shown in the diagram, inhibition of autophagy can also reduce antigen presentation via MHC class II molecules