Parasites' receptors for human transferrin and lactoferrin

Iron is an essential bio-element for all organisms including parasites. Within the human host, iron is sequestered to withhold it from pathogens. The iron binding proteins transferrin and lactoferrin, in particular, decrease the availability of iron for pathogenic micro-organisms in body fluids and mucosal surfaces. There is evidence that protozoan parasites possess specific receptors for the uptake of host transferrin and / or host lactoferrin to utilize these proteins as source of iron. The best characterized example is the transferrin receptor of Trypanosoma
brucei bloodstream forms which is a unique heterodimeric glycosylphosphatidylinositol-anchored protein complex. In this Chapter, the available information on transferrin / lactoferrin receptors of human protozoan parasites is summarized with particular emphasis on structure, biochemical properties and function of the well established T. brucei transferrin receptor.