Molecular mechanisms of host-pathogen interactions and their potential for the discovery of new drug targets.

Vaccines and chemotherapy have undeniably been the discoveries in the field of biomedical research that have exerted the biggest impact on the improvement of public health. Nevertheless, the development of bacterial resistance to antibiotics has co-evolved over time with the discovery of new drugs. This entails the necessity for continuous research on new anti-infectious agents. The current review highlights recent discoveries in the molecular mechanisms of specific host pathogen interactions and their potential for drug discovery. The focus is on facultative and obligate intracellular pathogens (Mycobacterium, Chlamydia and Legionella) and their manipulation of host cells in regard to inhibition of phagosome maturation and cell death. Furthermore, the composition and role of the SecA2 and the ESX-1 secretion pathways in bacterial virulence and manipulation of infected host cells is discussed. The central hypothesis proposed in this review is that the characterization of bacterial proteins and lipids involved in host cell manipulation (modulins) will provide an abundance of new drug targets. One advantage of targeting such bacterial modulins for drug development is that these anti-modulin drugs will not disrupt the beneficial host microflora and therefore have fewer side effects.