The Mechanism of T Cell Mediated Cytotoxicity. V. Morphological Studies by Electron Microscopy
The ultrastructural changes occurring when T cells specifically immune to antigens interact with P815 mastocytoma cells and EL4 lymphoma cells are described and related to changes previously observed by timelapse cinematography (Sanderson 1976b). In confirmation of work by others, pale T cells can c...
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Published in | Proceedings of the Royal Society. B, Biological sciences Vol. 198; no. 1132; p. 315 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
The Royal Society
05.09.1977
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Online Access | Get full text |
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Summary: | The ultrastructural changes occurring when T cells specifically immune to antigens interact with P815 mastocytoma cells and
EL4 lymphoma cells are described and related to changes previously observed by timelapse cinematography (Sanderson 1976b).
In confirmation of work by others, pale T cells can clearly be incriminated as cytotoxic cells. Dark T cells also form contacts
with target cells, and tend to project lamellipodia over the surface of the target cell. The possibility is discussed that
these represent a subset of non-cytotoxic, antigen-reactive T cells involved in other T cell functions. T cells form two types
of contact: relatively small point contacts, and large areas where the two plasma membranes are in close apposition. No structures
resembling specialized junctions or membrane fusions were observed in areas of contact between T cells and target cells. Close
contact between pale T cells and target cells is more regular than contact with dark T cells. Many contacts were seen between
morphologically normal target cells and pale T cells, and these were thought to occur in the phase between contact and target
cell death. Some of these pale T cells in contact show projections towards the centre of the target cell which invaginate
the cell membrane, but do not penetrate it. Remarkable T cell projections were also seen which had penetrated deeply through
the membrane of one target cell. These projections appeared to have disrupted the membrane and had penetrated into apparently
intact cytoplasm, suggesting that this penetration may be an early event in the lytic mechanism. The possibility that this
phenomenon is the cause of cell death is discussed. Changes corresponding to the phase of zeiosis of the target cell are described.
These commence with the formation of surface blebs, accompanied by a general mis-shapening of the cell outline and followed
by vacuolation and loss of cytoplasmic organelles. Breakdown of the nucleus appears to be a later, post mortem event. |
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ISSN: | 0962-8452 1471-2954 |
DOI: | 10.1098/rspb.1977.0100 |