Browsing by Author "Pardhasaradhi, B V"
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Item Conjugate formation between effector and target as a function of cytotoxicity in antibody-dependent killing of AK-5 tumor.(1995-03-01) Kausalya, S; Pardhasaradhi, B V; Manogaran, P S; Khar, AThe present study was carried out to mechanistically view a possible correlation between the process of, conjugate formation and its relation to target cell death. AK-5 killing is mediated by CD8+ natural killer cells through ADCC. Immune effectors on exposure to antibody primed AK-5 tumor cells formed tight conjugates. Ability of various cell types (NK, T, monocytes and macrophages) to form conjugates was evaluated. Marked increase in the number of NK cells binding to the target as compared to the other cell types was observed. Cytotoxicity of free and bound effectors against antibody tagged AK-5 cells demonstrated a reduced cytotoxic ability of the former in contrast to a significantly high lytic potential of the bound effectors. The results highlight the requirement for priming of NK cells which mediate killing of AK-5 tumor and provide additional evidence that formation of stable conjugates acts as the first signal for triggering lymphocyte activation and effective target cell lysis.Item Increased apoptosis in AK-5 tumor cells after transfection with wild type p53 gene.(1996-10-01) Pardhasaradhi, B V; Khar, AAK-5 tumor cell death is mediated through necrosis and apoptosis. The apoptotic activity in AK-5 cells has been studied after introduction of wild-type p53 gene. Apoptotic activity both in vitro and in vivo is significantly increased in p53 transfected cells. Similarly there is fragmentation of tumor cell DNA after undergoing apoptosis. These observations suggest an active participation of p53 in inducing apoptosis in AK-5 tumor cells.Item Induction of apoptosis in AK-5 cells by rotenone involves participation of caspases.(1999-04-05) Khar, A; Ali, A M; Begum, Z; Pardhasaradhi, B V; Varalakshmi, CAK-5 tumour cells undergo apoptosis after treatment with rotenone an electron transport inhibitor and oligomycin which inhibits mitochondrial ATPases. Apoptotic process involves the induction of caspases 2 and 3, whereas caspase 1 does not seem to be participating in rotenone/oligomycin induced apoptosis. DEVD which is a specific inhibitor of caspase 3, inhibited apoptosis in AK-5 cells. We have also observed a significant lowering of intracellular pH in AK-5 cells which are induced into the apoptotic process by rotenone. These results suggest an important role for mitochondrial electron transport in the induction of apoptosis in AK-5 tumour cells.