Purification and analysis of DNases of Tritrichomonas foetus: Evidence that these enzymes are glycoproteins

Reduction of Allergic Lung Disease by Mucosal Application of Toxoplasma gondii-Derived Molecules: Possible Role of Carbohydrates

Background

The hygiene hypothesis suggests a link between parasitic infections and immune disorders, such as allergic diseases. We previously showed that infection with Toxoplasma gondii or systemic application of T. gondii tachyzoites lysate antigen (TLA) in a prophylactic, but not therapeutic protocol, prevented allergic airway inflammation in mice. Here we tested the effect of prophylactic and therapeutic application of TLA via the mucosal route.

Methods

Mice were intranasally treated with TLA either i) prior to sensitization, ii) during sensitization and challenge, or iii) after sensitization with ovalbumin (OVA). Recruitment of inflammatory cells to the lung, cytokine levels in restimulated lung and spleen cell cultures as well as levels of OVA-specific antibodies in serum were measured. In parallel, the effect of native TLA, heat-inactivated (hiTLA) or deglycosylated TLA (dgTLA) on sensitized splenocytes was evaluated ex vivo.

Results

When applied together with OVA i) during systemic sensitization and local challenge or ii) exclusively during local challenge, TLA reduced infiltration of eosinophils into the lung, OVA-specific type 2 cytokines in restimulated lung cell cultures, and partially, type 2 cytokines in restimulated spleen cell cultures in comparison to allergic controls. No beneficial effect was observed when TLA was applied prior to the start of sensitization. Analysis of epitope sugars on TLA indicated a high abundance of mannose, fucose, N-acetylglucosamine, and N-acetylgalactosamine. Deglycosylation of TLA, but not heat-inactivation, abolished the potential of TLA to reduce type 2 responses ex vivo, suggesting a significant role of carbohydrates in immunomodulation.

Conclusion

We showed that mucosal application of TLA reduced the development of experimental allergy in mice. The beneficial effects depended on the timing of the application in relation to the time point of sensitization. Not only co-application, but also therapy in sensitized/allergic animals with native TLA reduced local allergic responses. Furthermore, we show that TLA is highly glycosylated and glycoconjugates seem to play a role in anti-allergic effects. In summary, given the powerful modulatory effect that TLA exhibits, understanding its exact mechanisms of action may lead to the development of novel immunomodulators in clinical application.

Variation in the saccharide lectin binding pattern from different isolates of Tritrichomonas foetus

Tritrichomonas foetus (T. foetus) is the causal agent of bovine tritrichomonosis (BT), a venereal disease that causes significant economic losses in the bovine livestock industry. The structural organization of T. foetus presents a cell membrane, an undulating membrane which extends along the parasite, three anterior flagella and a recurrent posterior flagellum. The interaction between the superficial glycoconjugates of the parasite and the host cell is one of the most relevant pathogenic mechanisms. In the present study, we analyzed the saccharide pattern through lectincytochemistry of the cell membrane, undulating membrane, cytoplasm and flagella of 28 isolates of T. foetus. Lectins that labeled most of the isolates were WGA, Con-A, RCA-I, LCA, GS-II and PHA-E showing the presence of D-mannose, D-glucose, N-acetylglucosamine and sialic acid. On the other hand, no labeling was observed in any of the structures with VVA, STA, LEA, Jacalin, GS-I, SJA, PHA-L, DSA, and weak labeling was observed with DBA, PNA, SBA and UEA I, showing therefore a low expression of N-acetylgalactosamine, L-fucose and galactose. In addition, GS II labeled in a granular pattern when lectincytochemistry was positive, whereas LCA strongly labeled the membranes and weakly the cytoplasms. The labeling variations observed among the isolates analyzed in the present work, could be related to differences in the pathogenic behavior of the isolates.