Most biotechnological therapeutics used in the clinic today and under current development, are of protein nature. Eukaryotic expression systems (such as yeasts and mammalian cells) for these therapeutic proteins add carbohydrate moieties (glycans) to the proteins, and these glycans strongly modulate the protein's in vivo biodistribution and therapeutic efficacy. Until recently, no adequate tools were available to accurately control glycosylation structure in these expression systems, but bio-engineering research in our lab and elsewhere has now largely overcome this problem.In the GlycoTarget ERC Consolidator grant project, we aim at exploring the relation between the structure of the glycans on therapeutic proteins and the in vivo targeting properties of these modified proteins to different tissues/cells/subcellular organelles.As highly medically relevant test cases for this exploration, we have selected three diseases with strong unmet therapeutic need, that could potentially be treated with glyco-targeted biopharmaceuticals through three different routes of protein delivery: progressive liver disease (intravenous), allergic asthma (subcutaneous immunization) and active tuberculosis (intrapulmonary delivery).