Abstract: The present invention provides novel compositions and methods useful in the, modulation or selective suppression of host immune responses to an immunogen of interest, particularly exogenous antigens and allergens such as urushiol, the active plant component causing poison ivy/oak contact sensitivity. The subject compositions are antibody molecules of either Ab.sub.1 or Ab.sub.2 (anti-idiotypic) reactivity with respect to the sensitizing antigen. Other compositions include specific T cell receptor (TCR) molecules either as T cell clones or hybridomas or as TCR preparations. Immunogenic peptides corresponding to some or all of the complementary determining regions or hyper-variable regions of the TCR are also employed. Such compositions suppress host immune responses to antigen by a variety of pathways including anti-idiotypic interactions with cells involved in antigen processing and stimulation of the immune network.

Abstract: The present invention provides novel compositions and methods useful in the modulation or selective suppression of host immune responses to an immunogen of interest, particularly to immunogens which are exogenous antigens or allergens. Subject compositions include antibody, antibody derived, and antibody-like molecules of primary antigen reactivity with respect to the immunogen of interest. Antibodies or antibody-like or antibody-derived molecules include antibody fragments such as Fab, and complementarity determining region peptides (CDRs) which may be grafted into a framework region of any species, particularly human. They also include human antibodies, derived from sensitized human lymphocytes produced by cell fusion with heterohybridomas, or by DNA cloning and expression. Other compositions include T cell receptor (TCR) molecules, obtained either from T cell clones or hybridomas or as purified TCR preparations.