Structure+-+Leishmaniasis

Leishmaniasis is caused bythe parasite //Leishmania.// The structure of //Leishmania// is similar to that of other kinetoplastids (single-cell flagellate protozoa): a free floating flagellum which has invagination, the flagellarpocket, asingular mitochondrion which includes a kinetoplast (a network of circular DNA - called kDNA), and several other common organelles.

On the outside, //Leishmania// have a lipophosphoglycan coat which covers the entire cell. Liphphosphoglycan is made up of two parts - a lipid and a glycan (polysaccharide), linked together by a strong "phosphodiester" covalent bond.

The layer is used by the parasite to modulate the immune response of the host; specifically, it helps the parasite continue to live within macrophages without being detected or killed by resisting the complement system, preventing natural killer cells from recognizing that the host macrophage is infected, and stopping the lethal oxidative burst from phagocytes.

When detected, lipophosphoglycan triggers Toll-like receptor 2, which then triggers an innate immune response.