I am greatly indebted to my doctor-father, Priv.-Doz. Dr. Peter Fischer, for guiding me through this work. I also thank Professor Saumweber, from the Department of Biology for his invaluable suggestions and support for me throughout this study. I heartily express my sincere gratitude to Professor Gaedicke and Dr. Uttenreuther-Fischer for their support and for making it possible for me to undertake this study at the laboratory of Pediatric Molecular Biology, Charite. I am also grateful to members of Dr. Fischerīs laboratory particularly Frau Lerch, for her excellent technical assistance particularly for the assay on the ‘binding of IVIG-selected Fabs to known B cell superantigens’. Also, I express my thanks to Professor Hagemeier and all others at the Pediatric Molecular Biology laboratory for their assistance and warm relationship during the course of this work. I wish also to say a big thanks to Henrike Zeller from Freiburg for translating the summary and conclusions in this thesis into German for me. I am also grateful to the Deutsche Forschungsgemeinschaft for funding the project.

I thank my Ghanaian Adventist friends in Berlin who made my stay in Berlin warmer, especially Mr. and Mrs. Boakye. I am also thankful to my parents in Ghana.

Last but not the least, I thank my wife, Nora, for her love, support, understanding, and encouragement, and our two lovely daughters Ivy and Kim who sometimes take off the weary from the laboratory. Nora, Ivy, and Kim thanks for being there when I needed you.