Insect-malaria parasites interactions: the salivary gland

Mosquito salivary glands are organs specialized in the production of a complex mix of molecules that digest carbohydrates from plant nectars, and facilitate blood feeding by the lubrication of mouthparts and the inhibition of homeostasis. Malaria sporozoites invade salivary glands and are injected with the saliva into vertebrate hosts during blood feeding. Sporozoites utilize molecules on their surface coat and outer pellicle membrane to adhere and invade specific regions of the salivary gland lobes. They transverse the secretory cells and are stored in the salivary duct, where transcription of new genes prepares them for vertebrate host invasion. Although it is probably that specific carbohydrate molecules on the surface of salivary glands function as parasites receptors, these have not been identified, neither other molecules nor mechanisms used by the parasite to invade, survive and mature within these organs. The recent advances in the sequence of the genomes of Anopheles gambiae and Plasmodium falciparum, and new developments in genomics and proteomics may help to elucidate the participating molecules, their regulation and interactions.