TLR4 and septic shock: On the other hand, natural LPS variants, or synthetic derivatives that are able to inhibit the activation of TLR4 by competing with toxic LPS or other agonists for TLR4/MD-2, are attractive candidates for drugs targeting pathogens that are caused by excessive TLR4 activation upon stimulation by bacterial LPS (sepsis and septic shock) [11,12,13,14,15].