Abstract: The invention provides methods for inhibiting immune responses by inhibiting the biosynthesis of the sialyl galactosides that are involved in immune responses. In particular, B lymphocyte-mediated immune responses are mediated by interfering with synthesis of &agr;2,6 sialylgalactosides, while T lymphocyte-mediated immune responses are inhibited by blocking synthesis of &agr;2,3 sialylgalactosides. The inhibition is accomplished by, for example, inhibiting the activity of a glycosyltransferase involved in synthesis of the respective sialyl galactoside.

Abstract: The invention relates to the use of genetically modified, very early haematopoietic and mesenchymal stem cells (negative for the expression of the surface molecule CD34) in the individual gene therapy of mono- or oligogenetic diseases or in cell therapy. Autologous CD34-negative adherently growing stem cell cultures from the peripheral blood of the patient are applied and efficiently tranfected or infected with genetic constructs. The gene products of these genes should substitute defective or absent proteins or factors in the patient organism in the long term. After expansion, the autologous stem cells can also be used for cell therapy (organ replacement therapy).

Abstract: The Na+/H+ exchanger isoform 1 (NHE-1) is primarily responsible for the regulation of the intracellular pH (pHi). It is a ubiquitous amiloride-sensitive growth factor activatable exchanger. There is a direct correlation between the pHi and cell cycle status of normal hemopoietic and leukemic cells, with leukemic cells having a higher pHi than normal hemopoietic cells. A method is provided to sort cells by flow cytometry into subpopulations of proliferating and non-proliferating cells and to induce apoptosis in proliferating leukemic cells by inhibiting the Na+/H+ exchanger, thereby lowering the internal pHi.

Abstract: Bacterial, yeast and animal cells and methods for overexpressing recombinant heparanase in cellular systems, methods of purifying recombinant heparanase therefrom and modified heparanase species which serve as precursors for generating highly active heparanase by proteolysis.

Abstract: Disclosed herein are hybridomas, antibodies produced thereby, antigens, and cells identified or isolated therewith. The dendritic like cells preferably have dendritic morphology and B cell phenotype. Methods of utilizing the hybridomas, antibodies, antigens, and cells are also discussed herein.

Abstract: Superantigens, including staphylococcal enterotoxins, are useful agents for killing tumor cells, enhancing antitumor immunity and treating cancer in a tumor-bearing host. Other useful superantigens include Streptococcal pyrogenic exotoxin, toxic shock syndrome toxins, mycoplasma antigens, mycobacteria antigens, minor lymphocyte stimulating antigens, heat shock proteins, stress peptides and derivatives thereof. The immune system of a subject with cancer is contacted with tumor cells that have been transfected with a nucleic acid encoding a superantigen or biologically active polypeptide of a superantigen. Alternatively, transfected accessory cells, inmunocytes or fibroblasts are used. Expression of the superantigen in the host induces T cell proliferation leading to increased antitumor immunity and tumor cell killing. The superantigen encoding nucleic acid may be administered to the tumor in vivo to transfect tumor cells, wherein superantigen expression induces a tumoricidal immune response.

Abstract: The present invention provides methods of proliferating B cells as a means of obtaining large numbers of B cells. The present invention further provides methods of differentiating a proliferating B cell population to antibody producing cells.

Abstract: A method of preparing an undifferentiated cell is described. The method comprises contacting a more committed cell with an agent that causes the more committed cell to retrodifferentiate into an undifferentiated cell.

Abstract: Provided by the invention are novel methods, vectors and cells for the recombinant production of desired gene products. In particular, the invention relates to increased production of desired gene products by inducibly arresting cell proliferation. The invention also provides novel multicistronic expression vectors that are useful not only for recombinant gene expression, but also for other applications such as gene therapy, tissue engineering and metabolic engineering.

Abstract: The invention provides a novel retroviral packaging system, in which retroviral packaging plasmids and packagable vector transcripts are produced from high expression plasmids after stable or transient transfection in mammalian cells. High titers of recombinant retrovirus are produced in these transfected mammalian cells and can then transduce a mammalian target cell by cocultivation or supernatant infection. The methods of the invention include the use of the novel retroviral packaging plasmids and vectors to transduce primary human cells, including T cells and human hematopoietic stem cells, with foreign genes by cocultivation or supernatant infection at high efficiencies. The invention is useful for the rapid production of high titer viral supernatants, and to transduce with high efficiency cells that are refractory to transduction by conventional means.

Abstract: The invention is directed to a method for the preparation of a conditionally immortalized immortalization-helper cell (fuseme), the fusemes generated by said method, hybridoma cells prepared using said fusemes as well as a method for immortalization of mammalian cells using said fuseme cells. Further, the invention relates to the generation of T cells directed agaist tumor cells using a fuseme cell.