Differential expression of genes related to the immune response of Anopheles (Nyssorhynchus) darlingi in the Brazilian Amazon Basin
Anopheles (Nyssorhynchus) darlingi is the primary vector of human malaria in South America. Immune responses in mosquito vectors of malaria are mainly regulated by genes of the Toll and IMD pathways through the transcription factors NF-kappa-β, Rel1 and Rel2, which are controlled by the negative regulatory genes Cactus and Caspar. We measured the expression levels of Rel1, Rel2, Caspar and Cactus genes, which are related to the immune system, in adult females of A. darlingi after blood feeding compared to adult females without blood feeding (controls) due to their possible effects on the ability of becoming infected with species of Plasmodium and spreading malaria. Quantitative expression was determined by real-time PCR, using the reference genes GAPDH and β-actin. The expression levels of Rel1, Rel2, Caspar and Cactus varied significantly at 4, 8, 14 and 24 h in mosquitoes that had fed on blood compared to control insects (0 h), with significantly greater expression at 24 h after blood feeding. Relative expression levels among these genes varied at the different post blood feeding times. This information adds to our understanding of the insect immune response system and related questions involved in understanding the biology and control of this mosquito.