Antje Denise Paulikat

• The studies presented here in this thesis investigated the complex interplay of the human respiratory tract pathogens S. pneumoniae, S. aureus and IAV with human APCs from two different perspectives. On the one hand, our findings demonstrated that pneumococci were able to completely suppress the function of moDCs and alter the subsequent activation of T cells. This immune evasion strategy is mainly based on the release of the pneumococcal virulence factor Ply. Furthermore, pneumococcal lipoproteins are becoming increasingly prominent as potential new serotype independent vaccine candidates. We show the favorable basic potential of the pneumococcal lipoprotein DacB and the significant impact of the attachment of a lipid moiety in a human context. Both, the lipidated version of DacB and MetQ, demonstrated robust activation of human APCs and further induced the proliferation of human CD4+ T cells underscoring the potential adjuvant properties of the lipid moiety.