Streptococcus pneumoniae capsular polysaccharide-mediated +CD4 T cell-dependent abscess formation requires IL-6 and TLR-4 Inaugural-Dissertation zur Erlangung des Doktorgrades Dr. nat. med. der Medizinischen Fakultät und der Mathematisch-Naturwissenschaftlichen Fakultät der Universität zu Köln vorgelegt von Sonja Meemboor aus Köln Köln, 2009 Gutachter: PD Dr. Pia Hartmann Prof. Dr. Karin Schnetz Tag der mündlichen Prüfung: 30. Oktober 2009 TTTToooo mmmm yyyy ppppaaaarrrreeeennnnttttssss Table of contents 1. Introduction............................................................................................................ 1 1.1 General introduction…………………………………………………………………. 1 1.2 Antigen-presenting cells …………………………………………………………….2 1.3 Antigen processing and MHC-dependent antigen presentation in APCs…...… 3 1.4 DCs stimulate T cell activation …………………………………………………….. 6 1.5 Superantigens and T cell-independent antigens…………………………………. 6 1.6 Zwitterionic polysaccharides as T cell-dependent antigens..…………………… 7 1.7 Peritonitis and abscess formation as a T cell-dependent immune response…. 8 1.8 Streptococcus pneumoniae………………………………………………………… 9 1.9 ZPS and Sp1 structure…………………………………………………………….. 10 + 1.10 ZPS-mediated CD4 T cell activation…………………………………………... 10 1.