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C Kasper

Publications and source records attributed to C Kasper.

41 records · Page 3Linked to original sources
PubMed1989

Studies of connective tissue mast cell-mediated cytotoxicity.

Although mast cells have been implicated in mediating antitumor activity, the kinetics, mechanism(s), and suspectibility of different tumors to mast cell-mediated cytotoxicity have not been defined. Rat connective tissue mast cells (CTMC) of greater than or equal to 99% purity were investigated in vitro and found to express maximal spontaneous cytotoxicity against the mouse fibrosarcoma cell line WEHI-164 (56.0% +/- 2.1 SEM), the ultraviolet B (UVB)-induced, cutaneous fibrosarcoma 5C25 (34.7% +/- 3.4 SEM), and the human renal cell tumor Currie (26.8% +/- 2.0 SEM) at an effector to target (E:T) ratio of 80:1. Kinetic studies of CTMC-mediated cytotoxicity demonstrated significant detectable lysis against these tumors within 8 h, which was maximal by 16 h. Binding experiments showed that CTMC formed conjugates with all three lytic-sensitive targets; however, CTMC also attached to the lytic-resistant target YAC-1, indicating that conjugate formation alone is not sufficient for mast cell-mediated cytotoxicity. At two different concentrations, mast cell granules (MCG) lysed WEHI-164 (36.5% +/- 6.8 SEM) and 5C25 (34.4% +/- 6.9 SEM), but were only slightly cytotoxic (5.7% +/- 2.9 SEM) against Currie. A potential role for tumor necrosis factor-alpha (TNF-alpha) in CTMC-mediated cytotoxicity also was investigated. Polyclonal antibodies to TNF-alpha greatly reduced CTMC and TNF-mediated lysis of WEHI-164, but only partially inhibited CTMC killing of the slightly TNF-sensitive 5C25 tumors, and had no effect on CTMC cytolysis of Currie. Thus, this study demonstrates that CTMC mediate cytotoxicity in vitro by both TNF-associated and TNF-independent mechanisms. We conclude that CTMC are capable of mediating antitumor activity and that this effect may be important for tumor surveillance in the skin and other sites.

Cell Line↗
PubMedDate not supplied

In vitro effects of recombinant human megakaryocyte growth and development factor on primary human tumour colony growth.

A study was made of the in vitro effects of recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) on breast, prostate, cervix and colon cancers. Tumour growth was assessed using a soft agar clonogenic assay. Stimulation of megakaryocyte numbers was seen in liquid culture following 10 ng/ml PEG-rHuMGDF. The same concentration led to no significant difference in colony-forming efficiencies for 22 of 25 tumour samples. A significant reduction in colony-forming efficiencies was seen for the remaining 3 specimens. These results suggest that PEG-rHuMGDF will not stimulate tumour growth in vivo.

Breast Neoplasms↗