The Gram-negative bacteria-binding protein gene family: its role in the innate immune system of anopheles gambiae and in anti-Plasmodium defence

Gram-negative bacteria-binding proteins (GNBPs) are pattern recognition receptors which contribute to the defensive response against Plasmodium infection in Anopheles . We have characterized the GNBP gene family in Anopheles gambiae at the molecular level, and show that they are functionally diverse components of the A. gambiae innate immune system. GNBPB4 is a major factor in the defence against a broad range of pathogens, while the other GNBP s have narrower defence specificities. GNBPB4 is associated with the regulation of immune signalling pathways and was found to interact with the Gram-negative Escherichia coli and weakly co-localized with Plasmodium berghei ookinetes in the mosquito midgut epithelium.