The goal of this research is to determine how the antigen receptor repertoire of the population of antigen-specific cytotoxic T lymphocytes (CTLs) derived from a previously immunized animal differs from that recognizing the same antigen but obtained from an immunologically naive donor. The CTL response to fluorescein-coupled cells will be used as a model system. A variety of structural homologues of fluorescein can be coupled to the surfaces of stimulator and target cells and used to define the fine specificity of the responding CTLs. An extensive number of short term monoclonal fluorescein-specific CTL populations will then be determined by analysis of the reactivity patterns of each of the clones on the panel of fluorescein homologues as well as variants of the stimulating major histocompatibility molecule. Simultaneously, methodologies for the derivation of long term clones of primary and secondary CTLs will be refined in order to ascertain the use of particular receptor gene combinations in early and late CTL populations. One of the proposed techniques for the generation of long term CTL clones which will be tested involves a novel, and potentially extremely useful application of hybridoma technology, in which DNA derived from a tumor cell is transfected directly into an activated CTL. The overall goal of this research is to further understanding of the nature of immunological memory. In particular, it asks the question: "How does the population of antigen-specific cytotoxic T lymphocytes derived from a previously immunized animal differ from that recognizing the same antigen but obtained from an immunologically naive animal?" Previous results from this laboratory have shown that cytotoxic lymphocytes from previously immunized animals are capable of recognizing cell surface attached antigen at a lower density than are lymphocytes from non-immune animals. The current research is directed toward determining the factor(s) controlling this difference. The results of this research should increase our fundamental understanding of the mechanism of immunological memory.
