Immune T lymphocyte to tumor cell adhesion. Magnesium sufficient, calcium insufficient.
The prelytic adhesion of immune cytolytic thymus-derived lymphocytes to specific antigen-bearing ascites tumor target cells has been studied. A new assay was used in which adhesions are permitted to form for 2.5 min; the cells are then dispersed to prevent further adhesion, and the predispersion adhesions are quantitated by subsequent 51Cr release from the tumor cells as a result of cytolytic activity of the adhering lymphocytes. There were the following new findings: (a) magnesium is sufficient to support optimal adhesion formation even when EGTA is added to remove contaminating traces of calcium; (b) calcium supports no adhesion formation when traces of contaminating magnesium are removed by pretreating the medium with a chelating ion exchange resin; (c) calcium synergizes with suboptimal magnesium, increasing the apparent adhesion-supporting potency of magnesium 20-fold in the presence of 50 microM calcium; (d) in the presence of optimal magnesium (2--4 mM), calcium has not effect on the properties of the adhesion by any of six criteria; and (e) manganese supports adhesion better than magnesium, and strontium is ineffective. A survey of previous literature indicates that these results are remarkably similar to the predominant pattern for nonimmunologic cell adhesion (e.g., fibroblasts) involving cells from a variety of tissues in late embryonic and adult avians and mammals. This suggests that a "magnesium sufficient, calcium insufficient" mechanism may be found among the latter types of cell adhesions when appropriately examined. Moreover, it seems that the present lymphocyte-tumor cell adhesion, although evoked by specific receptor-antigen recognition, relies predominantly on mechanisms common to nonimmunologic intercellular adhesion processes.
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects*; D002460:Cell Line; D004357:Drug Synergism; D004492:Edetic Acid / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000502:physiology*; D008274:Magnesium / Q000494:pharmacology*; D008345:Manganese / Q000494:pharmacology; D012515:Mast-Cell Sarcoma; D008670:Metals / Q000494:pharmacology; D051379:Mice; D013324:Strontium / Q000494:pharmacology
D008670:Metals; D008345:Manganese; D004533:Egtazic Acid; D004492:Edetic Acid; D008274:Magnesium; D002118:Calcium; D013324:Strontium