Compartimentalisation of common mucosal immune system between gut and lung in trichinellosis

GENTILINI MV, CALCAGNO M, SARACINO P, FALDUTO G, VENTURIELLO SM

Simposio; Keystone Symposia X5 Mucosal Biology: A Fine Balance between Tolerance and Immunity. Immunity in the Respiratory Tract: Challenges of the Lung Environment (X6).; 2011

The parasite disease caused by Trichinella spiralis induces a response of the mucosal immune system (MIS) which leads to the rejection of adult worms (AW) from the intestine. We have recently demonstrated in Wistar rats that, simultaneously to this intestinal response an inflammatory lung tissue is generated, featured by humoral, cellular and functional changes that are finally biased towards a Th2-type immune response. Considering that this parasite has a migratory stage (ms) and that during its way to striated muscles from day 5 pi on it goes through different organs including lungs, the aims of this work were to evaluate the role of the lung as a site for parasite retention and destruction by analyzing: 1-the presence of specific antibody (Ab) isotypes to the ms surface in lung tissue extracts (LTE, n=8/dpi) by the indirect immunofluorescence test, 2-the cytotoxic capacity of lung cells and Ab against the ms by antibody-dependent cell cytotoxicity assays, and 3-the presence of ms in sections (H&E) and in enzymatic homogenates of the lung. Results showed 1-local production of anti-ms surface Abs of the infected rats: IgG2a, IgE, IgG1 and IgA. 2-cytotoxic capacity of lung cells in the presence of anti-ms Abs (ms mortality %: 87±13 vs. 13±1, with and without Abs respectively). Studies suggest the existence of a higher cytotoxic capacity of lung cells on day 6 pi in the presence of anti-ms Abs and 3-presence of ms in lung alveoli, parenchyma and enzymatic homogenates. These results postulate the lung as one of the parasite retention and destruction sites. Thus, the immunological protective mechanisms against T. spiralis during infection are developed at the intestinal (AW) and lung mucosal levels (ms). The correct stimulation of the host’s MIS by specific immunization protocols could lead to the protection against Trichinella infection.