This volume discusses various basic and advanced methods and prools that have been proven to be successful among certain bacterial species, or a family of species, in type III secretion systems (T3S system). The chapters in this book cover topics such as: site—directed mutagenesis and its application in studying the interactions of T3S components; use of transcriptional control to increase expression and secretion of heterologous proteins in T3S systems; fractionation techniques to examine effector translocation; detecting immune responses to T3S systems; mouse immunization with purified needle proteins from T3S systems and the characterization of the immune responses to these proteins; and detection of protein interactions in T3S systems using yeast 2—hybrid analysis. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step—by—step, readily reproducible laboratory prools, and tips on troubleshooting and avoiding known pitfalls. Practical and comprehensive, Type 3 Secretion Systems: Methods and Prools is a valuable resource for anyone interested in learning about the fascinating and ever—changing T3S systems.