Identification of immune-related genes expressed in the fat body of Ixodes ricinus ticks

Fat body of invertebrate animals is next to the hemocytes the primary tissue producing a number of immune-related molecules that serve in humoral defense against microbes invading the hemocoel. In contrast to insects, nothing is known about immune-related molecules expressed in the fat body of ticks. The tick fat body cells are tightly associated to the tracheal trunks making their physical separation impossible. The RNAseq analysis was performed using four individual wild-caught Ixodes ricinus females that naturally fed on guinea pig for six days (semi-engorged state). This approach allowed a semi-quantitative expression profiling based on the FPKM (TPM) values of transcripts and evaluate expression variability in individual ticks.