Use of the air pouch model to investigate immune responses to a hookworm vaccine containing the Na-ASP-2 protein in rats.

Hookworms are gastrointestinal nematodes that affect approximately 600 million people in developing countries. Using the air pouch model, we have examined the effects of vaccination with the recombinant hookworm larval antigen Na-ASP-2 and the adjuvant Alhydrogel on the skin immune response to hookworms in Sprague Dawley rats. Following vaccination, rats were inoculated 100 Necator americanus L3 into the air pouch, and the exudates and cell infiltrates were collected from the pouch 24 h later. Larval inoculation induced leucocyte recruitment into the pouch. Exudates of rats vaccinated with Na-ASP-2 showed an increase of cytokines such as IL-4, IL-10, IFN-gamma and especially, IL-5, as well as IgG1 and IgG2 antibodies. The increased amount of antigen-presenting cells and cytokines in the pouch of vaccinated animals suggests that vaccination could potentially restrain this parasite to the inoculation site, avoiding its migration and establishment in the host. Moreover, the air pouch model could constitute an alternative to screen immune responses to L3 antigens.