A mosquito juvenile hormone binding protein (mJHBP) regulates the activation of innate immune defenses and hemocyte development
Fig 3
Effect of mJHBP deficiency on innate immune responses after bacterial challenge.
A. mJHBP-/- (KO) mosquitoes are unable to control bacterial infection. Bacterial counts (CFU) from 3 biological replicates of 2–4 individual WT and KO mosquitoes infected with E. coli (OD600 = 0.1) 24 (n = 8), 48 (n = 10) and 72 h (n = 11) post-infection. Significance levels (Mann-Whitney U test) are indicated as asterisks (**** p ≤ 0.0001, *** ≤ 0.001, ** ≤ 0.01, * ≤ 0.05). Median values are shown as horizontal lines. Mortality of E. coli-injected mosquitoes was negligible. B. Effect of mJHBP deficiency on the survival of mJHBP-/- (KO) mosquitoes. Kaplan-Meier survival curves for WT (n = 20) and KO (n = 17, two biological replicates) females infected by S. marcescens (OD600 = 0.05) shows that KO mosquitoes succumbed earlier than WT females. The median survival between WT and KO mosquitoes was statistically significant (Log-rank test, p≤0.0001). C,D. Effect of mJHBP deficiency on the expression of the antimicrobial peptides defensin A (C) and cecropin A (D) in the fat body of E. coli-challenged females measured at 6, 24, 48 and 72 h post-infection (n = 9, 3 biological replicates of 3 individuals). mJHBP-/- (KO) mosquitoes exhibited a 24 h delay in the induction of both AMPs. Changes in expression were calculated by comparing the ΔCt of infected mosquitoes with that of LB-injected mosquitoes (2-ΔΔCt). Black arrow: time of induction to maximum expression level in the WT strain = 24 h; Magenta arrow: time of induction to maximum expression in the KO strain = 48 h. Data were analyzed using the Mann-Whitney U test (**** p ≤ 0.0001). Again, mortality of E. coli-infected mosquitoes was negligible.