Following infection by N. ceranae, a large number of genes coding for serine proteases were modulated (SP17, SP18, SP22, SP34, SP35, SP36, SP40, SP44, SPH19, SPH42,SPH50) at days 5, 10 and 15 P.I. The serine proteases are implicated in the immune response for Drosophila where 94 out of 201 serine protease genes are involved in diverse immune protease cascades [53]. This evidence concerns the gene PRDX3 and infection.