B cell responses in vaccination and chronic viral infection

In order to develop a suitable and tailored vaccine providing protection against a disease, it is key to understand the mechanisms that underly immune control of the infection as well as the mode of action of the vaccine. To address both elements, we first developed a tool to facilitate the study of lymphocyte subsets in vivo. Therefore, we engineered Adeno-associated viral vectors (AAVs) to deliver various depletion antibodies (depletion-AAVs) targeting lymphocyte subsets that allow for the long-term elimination of such after a single administration. Depletion-AAVs permit the simultaneous elimination of several lymphocyte subsets and can be administered to mice of different genetic background. By employing depletion-AAVs, we gained new insights into the mechanisms that underly immune control of chronic viral infection and identified the fundamental role of B cells therein. Furthermore, we provided a detailed characterization of the B cell response induced by a novel and promising vaccine candidate, the recombination Orf virus vector, which could ultimately serve to prevent chronic infection.