Abstract: A method for detecting and quantifying of the frequency of T cells to multiple antigenic peptide epitopes comprising: measuring intracellular Ca2+ signaling in individual T cells that are labeled with Ca2+ sensitive fluorophore; wherein said T cells are placed on the glass bottom of a well-covered with antibodies or other capturing proteins specific for non-stimulatory T cells' surface receptors and wherein a peptide antigens are injected into the well and the peptide binds to MHC molecules on the T-cell surface, wherein an increase in the intracellular concentration of Ca2+ in responding T cells leads to rise in intracellular fluorescence that is detected by fluorescent microscope and wherein the response rate of said detected fluorescence can be utilized to determine the quantity of responding T cells and the efficiency of said cells.

Abstract: A method for detecting and quantifying of the frequency of T cells to multiple antigenic peptide epitopes comprising: measuring intracellular Ca2+ signaling in individual T cells that are labeled with Ca2+ sensitive fluorophore; wherein said T cells are placed on the glass bottom of a well-covered with antibodies or other capturing proteins specific for non-stimulatory T cells' surface receptors and wherein a peptide antigens are injected into the well and the peptide binds to MHC molecules on the T-cell surface, wherein an increase in the intracellular concentration of Ca2+ in responding T cells leads to rise in intracellular fluorescence that is detected by fluorescent microscope and wherein the response rate of said detected fluorescence can be utilized to determine the quantity of responding T cells and the efficiency of said cells.

Abstract: A method for detecting and quantifying of the frequency of T cells to multiple antigenic peptide epitopes comprising: measuring intracellular Ca2+ signaling in individual T cells that are labeled with Ca2+ sensitive fluorophore; wherein said T cells are placed on the glass bottom of a well-covered with antibodies or other capturing proteins specific for non-stimulatory T cells' surface receptors and wherein a peptide antigens are injected into the well and the peptide binds to MHC molecules on the T-cell surface, wherein an increase in the intracellular concentration of Ca2+ in responding T cells leads to rise in intracellular fluorescence that is detected by fluorescent microscope and wherein the response rate of said detected fluorescence can be utilized to determine the quantity of responding T cells and the efficiency of said cells.

Abstract: The present invention relates to a method of inhibiting graft-versus-host disease in allogeneic hematopoietic stem cell transplant (HSCT) patients by using L-leucyl-L-leucine methyl ester (LLME) to eliminate selective cytotoxic T cells in donor lymphocyte infusions (DLI). LLME has been shown to inhibit GVHD in animal models by selectively inducing apoptosis in natural killer cells and cytotoxic T cells. The application of LLME to the human clinical HSCT situation, however, has been hampered by HSC toxicity when unseparated marrow is treated at the concentrations necessary to purge GVHD-inducing T cells prior to infusion. In the present invention, this problem is circumvented by the LLME ex vivo treatment of DLI administered following transplantation of T cell-depleted HSC. In this setting, the effects of LLME on HSC contained within the DLI are irrelevant for clinical outcome.