IL9 and infection: In summary, the results of the present study suggest that the treatment of the AKR/OlaHsd mice susceptible to infection by T. muris, by the nasal immunization with the recombinant peptide rPP2A as a lipopeptide bound to OVS and administered at the outset of the chronic phase of infection, is able to activate a combined Th17/Th9 response orchestrated by the cytokines IL-25, IL-17 and IL-9, restraining egg release by intestinal worms and resulting in accelerated worm expulsion.