The goal of the proposed work is to further our understanding of the differences between the immune responses of previously- immunized (secondary) and naive (primary) animals to T-dependent antigens. The system to be used is the response to the hapten, fluorescein, and both B cell and Cytotoxic T Lymphocyte (CTL) responses will be studied. It is hypothesized that, since the eventual effector phase of the B cell immune response involves an antibody molecule, whereas the end-stage of the CTL response resides in a cell-cell mediated interaction, the modes of maximizing the effectiveness of the two types of secondary immune responses may differ. The work to be carried out includes an analysis of the molecular basis of memory in the IgM response to fluorescein. These experiments are prompted by the observation of an apparent dichotomy of V region gene use in the primary and secondary IgM responses to fluorescein. Investigations of the CTL anti-fluorescein response will include limiting dilution analyses of primary and secondary CTLs, immunofluorescent studies of the density and arrangement of a variety of molecules on the surface of CD8-positive T cells, and an genetic study of the T cell receptor molecules used in primary and secondary CTL responses. There is a great need for such an in-depth analysis, which is expected to lead to an understanding of differences between primary and secondary immune responses. The CTL projects, in particular, are likely to yield fundamental advances in the field. In addition, since the work will be carried out in a predominantly undergraduate setting, with student collaborators-in-training, the projects will have enormous impact in terms of its contribution to science education at the undergraduate level.
