This is a Career Advancement Award to support Dr. Owen's sabbatical studies in the laboratory of Dr. Andrew Caton at the Wistar Institute in Philadelphia. Dr. Owen's goal is to learn molecular genetic techniques such as gene sequencing, in order to apply them to her ongoing studies on the changes in ligand repertoire expression which accompany immune memory generation. By expanding her expertise in this way, Dr. Owen will be poised to make significant new contributions to the question of how immune memory and secondary immunization are translated into diversification of V region genes for a given hapten. The skills to be learned, and the results to be obtained from their application to Dr. Owen's research problem, are anticipated to significantly enhance Dr. Owen's career.