Mouse Anti-Human CR2 Hybridoma [UIC-6]

Natural killer (NK) cell-mediated cytotoxicity is traditionally measured using the chromium release assay, which measures the fraction of radioactive Cr-51 released from dying target cells co-cultured with NK cells. However, the time frame of (51)Cr2 release assays is limited to approximately 4 h due to spontaneous release of Cr-51. In the tumor microenvironment, interactions between NK cells and tumor cells occur over extended time periods, and NK cell-mediated cytotoxicity is modulated by cytokines produced by tumor cells and other immune cells. Here we demonstrate that the interaction of NK cells and tumor cells can be imaged and quantified over an extended period of time using a novel image cytometry method. Specifically, we imaged killing of human ZsGreen(+) melanoma cells by primary human NK cells in the presence of an antibody targeting MICA and MICB on the tumor cell surface. The number of live ZsGreen(+) A375 cells was counted in 96-well plates over a three day time frame, and the results were used to first calculate % specific killing at the 4 h time point to compare to Cr-51 release assay. Analysis of data from the 4 h time point demonstrated that both Cr-51 and image cytometry enable sensitive detection of NK cell-mediated killing of tumor cells. Image cytometry demonstrated that the combination of the MICA/B antibody and IL-2 induced near-complete eradication of A375 melanoma cells by NK cells at later time points. This novel image cytometry based approach will be suitable for the discovery of combination therapies that enhance the cytotoxic function of NK cells against tumor cells.

Five chromium(iii) chloride complexes, [2-{(Ar)N=CMe}-9-{N(Ar)}C10H10N]CrCl3 (Ar = 2,6-Me(2)C(6)H(3)Cr1, 2,6-Et(2)C(6)H(3)Cr2, 2,6-i-Pr(2)C(6)H(3)Cr3, 2,4,6-Me(3)C(6)H(2)Cr4, 2,6-Et-2-4-MeC(6)H(2)Cr5), each chelated by a sterically and electronically different cycloheptyl-fused N,N,N'-bis(imino)pyridine, have been synthesized by the reactions of CrCl3(THF)(3) with the corresponding ligand (L1/L1'-L5/L5'). The molecular structure of Cr2 highlights both the steric properties exerted by the inequivalent N-2,6-ethylphenyl groups and the puckering of the fused cycloheptyl ring; a distorted octahedral geometry is conferred about the metal center. On activation with methylaluminoxane (MAO) or modified MAO (MMAO), Cr1-Cr5 displayed their optimal activity for ethylene polymerization at temperatures between 70 and 80 degrees C with the least sterically demanding Cr1 proving the most productive (1.44 x 10(7) g (PE) per mol (Cr) per h). The polyethylenes formed are of low molecular weight (M-w range: 0.66-3.56 kg mol(-1)) with narrow molecular weight distributions and display high levels of end-group unsaturation. Furthermore, the amenability of these vinyl-terminated polyethylenes to undergo functionalization via epoxidation has been demonstrated.