Fluor 20/0.45 objective lens (Nikon) and a Magnafire digital charge-coupled device camera.Biodistribution Studies in 5TGM1 Tumor-bearing Mice5TGM1 tumor bearing mice were sacrificed at 2 or 24 h after the injection of the radiopharmaceutical, 64Cu-CB-TE1A1PLLP2A. Blood, marrow, fat, heart, stomach, intestines, lungs, liver, spleen, kidneys, muscle, bone, pancreas, and tumor were harvested, weighed, and counted in the c-counter. For the in vivo blocking studies, an additional group of mice was injected with the radiopharmaceutical premixed with 
,200-fold excess of LLP2A to serve as a blocking agent and sacrificed at the respective time point. The percent injected dose per gram of tissue ( ID/g) was determined by decay correction of the radiopharmaceutical for each sample normalized to a standard of known weight, which was representative of the injected dose.5TGM1 cells demonstrated high expression (.85 of cells staining positive) of a-4 by flow cytometry when normalized to the isotype control (Figure 2A). The cellular uptake (sum of the cellinternalized and cell surface-bound fractions) at 37uC of 64Cu-CBTE1A1P-LLP2A in 5TGM1 cells in the presence and absence of the blocking agent (non-radiolabeled ligand, LLP2A) was significantly different (p,0.0001, Figure 2B). The in vitro binding affinity of 64Cu-CB-TE1A1P-LLP2A was investigated by determining the equilibrium dissociation constant (Kd) and the maximum specific binding (Bmax) of the radiolabeled conjugate to 5TGM1 cells in saturation binding assays. A large excess (200-fold excess) of unlabeled LLP2A was added to a parallel set of cells to MedChemExpress Potassium clavulanate saturate receptor binding sites and account for non-specific binding. A representative saturation binding curve and Scatchard transformation of 64Cu-CB-TE1A1P-LLP2A to 5TGM1 cells is shown in Figure 2C. The data show that in the concentration range of 0.5?5.5 nM, 64Cu-CB-TE1A1P-LLP2A is bound to a single class of binding sites with a Kd of 2.2 nM (60.9) and Bmax of 136 pmol/mg (619).Biodistribution of 64Cu-CB-TE1A1P-LLP2A in 5TGM1 Tumor Bearing Immunocompetent/KaLwRij MiceIn vivo biodistribution of 64Cu-CB-TE1A1P-LLP2A was evaluated in KaLwRij mice bearing subcutaneous 5TGM1 tumors (Figure 3). Uptake of the radiotracer was high in the 5TGM1 tumors (12.0464.50 ID/gram). As expected, tracer uptake was highest in the VLA-4 rich hematopoietic organs, spleen (8.861.0 ID/gram) and marrow (11.662.1 ID/g). In a separate cohort of tumor-bearing mice, excess of cold LLP2A ligand was co-administered with 64Cu-CB-TE1A1P-LLP2A. In the presence of the blocking agent, the radiotracer uptake was significantly reduced in the tumor, spleen and bone (p,0.05), demonstrating the in vivo binding specificity of 64Cu-CB-TE1A1PLLP2A (Figure 3, open bars). Biodistribution of 64Cu-CBTE1A1P-LLP2A in non-tumor bearing KaLwRij mice was simi.Amber apparatus using pre-casted QuickGels (Helena Laboratories) 1379592 according to manufacturer’s instruction. Densitometric analysis of the SPEP traces was performed using the clinically certified Helena QuickScan 2000 workstation, allowing a precise quantification of the various serum fractions, including the measurements of gamma/albumin ratio.Cu-CB-TE1A1P-LLP2A Binding to VLA-4 in 5TGM1 Murine Myeloma CellsHistological AnalysisAfter sacrifice from the biodistribution and the small animal imaging studies, the tumor sections were stained with hematoxylin and eosin (H E) and visualized under a Nikon Eclipse TE300 microscope equipped with a Plan Fluor 20/0.45 objective lens (Nikon) and a Magnafire digital charge-coupled device camera.Biodistribution Studies in 5TGM1 Tumor-bearing Mice5TGM1 tumor bearing mice were sacrificed at 2 or 24 h after the injection of the radiopharmaceutical, 64Cu-CB-TE1A1PLLP2A. Blood, marrow, fat, heart, stomach, intestines, lungs, liver, spleen, kidneys, muscle, bone, pancreas, and tumor were harvested, weighed, and counted in the c-counter. For the in vivo blocking studies, an additional group of mice was injected with the radiopharmaceutical premixed with ,200-fold excess of LLP2A to serve as a blocking agent and sacrificed at the respective time point. The percent injected dose per gram of tissue ( ID/g) was determined by decay correction of the radiopharmaceutical for each sample normalized to a standard of known weight, which was representative of the injected dose.5TGM1 cells demonstrated high expression (.85 of cells staining positive) of a-4 by flow cytometry when normalized to the isotype control (Figure 2A). The cellular uptake (sum of the cellinternalized and cell surface-bound fractions) at 37uC of 64Cu-CBTE1A1P-LLP2A in 5TGM1 cells in the presence and absence of the blocking agent (non-radiolabeled ligand, LLP2A) was significantly different (p,0.0001, Figure 2B). The in vitro binding affinity of 64Cu-CB-TE1A1P-LLP2A was investigated by determining the equilibrium dissociation constant (Kd) and the maximum specific binding (Bmax) of the radiolabeled conjugate to 5TGM1 cells in saturation binding assays. A large excess (200-fold excess) of unlabeled LLP2A was added to a parallel set of cells to saturate receptor binding sites and account for non-specific binding. A representative saturation binding curve and Scatchard transformation of 64Cu-CB-TE1A1P-LLP2A to 5TGM1 cells is shown in Figure 2C. The data show that in the concentration range of 0.5?5.5 nM, 64Cu-CB-TE1A1P-LLP2A is bound to a single class of binding sites with a Kd of 2.2 nM (60.9) and Bmax of 136 pmol/mg (619).Biodistribution of 64Cu-CB-TE1A1P-LLP2A in 5TGM1 Tumor Bearing Immunocompetent/KaLwRij MiceIn vivo biodistribution of 64Cu-CB-TE1A1P-LLP2A was evaluated in KaLwRij mice bearing subcutaneous 5TGM1 tumors (Figure 3). Uptake of the radiotracer was high in the 5TGM1 tumors (12.0464.50 ID/gram). As expected, tracer uptake was highest in the VLA-4 rich hematopoietic organs, spleen (8.861.0 ID/gram) and marrow (11.662.1 ID/g). In a separate cohort of tumor-bearing mice, excess of cold LLP2A ligand was co-administered with 64Cu-CB-TE1A1P-LLP2A. In the presence of the blocking agent, the radiotracer uptake was significantly reduced in the tumor, spleen and bone (p,0.05), demonstrating the in vivo binding specificity of 64Cu-CB-TE1A1PLLP2A (Figure 3, open bars). Biodistribution of 64Cu-CBTE1A1P-LLP2A in non-tumor bearing KaLwRij mice was simi.