Abstract: The invention is based on the discovery that the cytosolic metalloendopeptidase, thimet oligopeptidase (TOP, EC3.4.25.15) has been found to play a key role in modulating levels of MHC class I-presented peptides, and in doing so, modulates the extent of antigen presentation on cell surfaces. Thus, compositions that affect the presence and/or levels of TOP, and processes to control the presence and/or levels of TOP, can be utilized to modulate antigen presentation on cell surfaces, and thereby enhance the acquisition of cell-based immunity, or alternatively, enhance cell-mediated killing of undesirable cells.

Abstract: The present invention relates to various methods of genetic immunization for the purpose of providing antigen-specific immunity in a mammalian host, including a human host. The invention is based on the ability to direct particulate polynucleotides which express an antigenic protein or protein fragment to the cytoplasm of host target cells, such as antigen presenting cells. A directed delivery of such particulate polynucleotides to the cytoplasm of antigen presenting cells will stimulate antigen-specific CTL production, thus promoting destruction of affected cells such as neoplastic cells and virally infected cells.

Abstract: The invention provides compositions and methods for inducing MHC class I-restricted cytotoxic T lymphocyte responses in a mammalian host by immunization with non-replicating protein antigens. The compositions of the invention comprise a two-component complex including a particle component, which is not a prokaryotic or eukaryotic cell, or a micellar, multimicellar, or liposome vesicle composed of detergents and/or lipids, ranging in size from about 10 nm to about 50 &mgr;m, and a non-replicating protein antigen. The non-replicating protein antigen is attached to the particle component through a covalent or non-covalent association to form particulate protein antigen complexes and the complexes are administered to a mammalian host in conjunction with a pharmaceutically acceptable excipient, in a CTL-stimulatory amount. The invention also provides non-replicating vaccines and methods of vaccinating a mammalian host for CTL immunity.

Abstract: The present invention relates to prophylactic and therapeutic methods of anti-tumor immunization. These methods are based on cross-priming a mammalian host to natural MHC class I restricted tumor antigens with an artificial tumor antigen. A primary tumor is resected from the patient and a population of tumor cells are cultured in vitro. These cultured tumor cells are loaded with an artificial target antigen. The loaded tumor cells are inactivated and introduced into the patient either simultaneous or subsequent to a direct immunization of the patient with the same or substantially the same artificial target antigen. This method of coupled host immunization promotes a tumor specific cytotoxic T lymphocyte (CTL) immune response against multiple, undefined natural tumor antigens expressed on the unmodified tumor cell surface.

Abstract: The present invention provides a method for enhancing the association of exogenous peptides with class I MHC molecules on the surface of antigen presenting cells to thereby sensitize the target cells for class I MHC-restricted cytotoxic T cell response. The method involves obtaining the peptides of interest and presenting the peptides to the appropriate antigen presenting cells in the presence of an elevated level of free .beta..sub.2 -microglobulin.The method of the present invention can also be used to prime naive populations of T lymphocytes for antigen-specific class I MHC-restricted cytotoxic T cell response with exogenous peptide and is useful in both in vitro and in vivo applications. A new use for purified .beta..sub.2 -microglobulin as an adjuvant for synthetic peptide vaccines is also provided.

Abstract: The present invention provides class I MHC-restricted T-T hybridomas, a novel T-T fusion partner therefor and an assay system that allows for the generation and detection of functional, class I MHC restricted T-T hybridomas. The fusion partner comprises a murine BW5147 cell line that has been transfected with a CD8 gene and stably expresses the CD8 gene product. The BW5147 transfectants are used to generate functional, class I MHC restricted T-T hybridomas which are permissive for lymphokine production. Functional class I MHC-restricted T-T hybridomas exhibiting the capability of producing lymphokines are prepared by fusing BW5147 cells expressing CD8 with T lymphocytes activated in a mixed leukocyte reaction (alloreactive T cells) or stimulated with antigen (antigen-stimulated T lymphocytes) and screening the resulting hybrids for the ability to produce lymphokines in response to appropriate antigenic stimulation.