This volume discusses various basic and advanced methods and protocols 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 protocols, and tips on troubleshooting and avoiding known pitfalls. Practical and comprehensive, Type 3 Secretion Systems: Methods and Protocols is a valuable resource for anyone interested in learning about the fascinating and ever-changing T3S systems.