Figure 2

L. lactis can bridge the gaps towards Ag-specific immune therapy. State of the art research on (auto-) immune diseases allows for mechanistic understanding of these pathologies, in terms of onset, precise localization (red circle), cellular compartment and specificity of the auto-Ag (Ag; wedge). The current standard of care exists of systemic immune suppression which may alleviate some aspects of the immune pathology but very often, due to its systemic and Ag-nonspecific nature, comes associated with moderate to even severe toxicity in otherwise non-affected organs. Purified Ag (blue triangle), delivered through the oral route, aims to make proficient use of inherent oral tolerance induction at the intestinal mucosal immune system to provoke Ag-specific suppression of the immune disease without affecting areas that do not share the Ag (X). This route of administration however suffers from major practical obstacles which make it difficult to administer sufficient, high quality Ag to the intestinal mucosa. To circumvent this, recombinant L. lactis expressing the Ag (blue circle holding white triangle) can be delivered through the oral route. These bacteria can then synthesize Ag of reproducible quality directly at the intestinal immune system and by co-synthesis of immune modulatory components can further enhance tolerance induction. In this way, Ag-specific oral tolerance induction is rendered practically feasible.