Preface

The aim of this special issue of Current Protein and Peptide Science is to provide a useful range of validated peptide-based tests potentially useful for diagnosis or for studying at the eptitope level the reactivity of antibodies. The authors also discuss some aspects of the T cell response. This issue starts off with a comprehensive introductory chapter to epitope mapping principles. The next manuscripts demonstrate that peptide-based immunoassays hold a lot of promise for the diagnosis of various autoimmune (chapter 2), neurological (chapter 3) and infectious (chapters 4-6) diseases. Always more specificity, more sensitivity, rapidity, and extent and diversity of available antigen libraries are required for developing accurate and relevant diagnostic tests. This is achieved by a growing diversity of methods and new technologies involving highly sensitive miniaturised sensors. In this context, synthetic peptides are candidates of choice because there can be produced in large amount in a completely controlled manner, they can be chemically modified with natural or unnatural residues, and their structure can be changed by cyclization or multipresentation on chemical or inert supports and carriers developed to increase their antigenicity. An extraordinary potential also comes from the development of peptide mimics and mimotopes. Novel approaches aimed to improve the stability of peptides to proteases have also been described. Selected synthetic peptides can thus advantageously replace natural proteins, which are rare or difficult to purify, and recombinant proteins, which sometimes also pose some problem of purification and antigenicity. Future work will certainly give us more analytical tools to cover the diversity of expected response useful for a precise and early diagnostic. The objective of this issue was twofold. First to provide in a condensed package a forum for the description of recent advances in the domain of antigenicity of proteins and peptides presented under the form of individual chapters dealing each with a specific focus. At the frontier of immunology, biochemistry and chemistry, the information is generally available in a large range of scientific and clinical journals and it is often impossible to keep apace this information overload. Second to discuss the potential of old or novel technologies in the domain of peptide-based diagnosis with their respective scope and limitations. The contributors have illustrated their approach with results from their own research as well as from the literature. Their conclusion is often a message of hope claiming that from a specific and early diagnosis, can emerge a better and a shorter-term treatment with less side effects and an improved patients' quality of life. We hope that these informative articles will provide some stimulus for further discovery.