Scanning Microscopy


Various forms of cellular injury, whether induced by immune effector cells, aberrant metabolic processes, chemotherapeutic drugs or temperature shifts, result in common morphological changes consisting of the formation and shedding of membrane vesicles from the injured cell surfaces, i.e., apoptosis. This dynamic cell surface membrane behavior appears to be dependent on the disruption of cytoplasmic microtubules. Concomitant with the altered cell surface morphology, certain physiological and biochemical events have been found to be associated with cell injury. These include changes in membrane permeability, elevated oxygen consumption rates and nuclear DNA fragmentation. However, it remains to be experimentally established which of these biological changes defines a state of irreparable cell injury and/or programmed cell death (PCD).

Selective cell injury and death is the goal of many therapeutic modalities aimed at the destruction of malignant cells. On the other hand, prevention of cell injury is desirable in autoimmune diseases such as systemic lupus erythematosus, thyroiditis, insulin dependent diabetes and many others. Injury to the vascular endothelium may play a role not only in thrombosis, atherosclerosis and hypertension, but may also provide the avenues for the metastasis of malignant cells.

The objective of the present review is to compare and evaluate the cell injury process induced by effector lymphocytes with that caused by low temperature. The latter mimics most, if not all, the currently known criteria of immune effector cell mediated PCD of target tumor cells.

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