Chemotactic selection with insulin, di-iodotyrosine and histamine alters the phagocytotic responsiveness of Tetrahymena

Chemotactic selection is a method by which populations of cells exposed to ligands can be isolated and subsequently cultivated. We used Tetrahymena py riformis GL cultures selected by chemotactic selection to insulin (10 nM), histamine (0.1 nM) and di-iodotyrosine (T2, 10 nM) to study the phagocytoti c capacity under the induction of selector hormones. Our results show a lon g-lasting link between chemotactically selected cultures and phagocytotic a ctivity. Cells selected to histamine produced the highest phagocytotic acti vity upon a second exposure to the selector hormone. T2 selection was also strongly effective, however, the phagocytosis stimulation was not specific to the hormone given later. Insulin selected sub-populations had different phagocytotic responses to the control substance itself, whereas histamine s elected sub-populations seem to be heterogeneous in the phagocytotic respon se to histamine. For insulin, the increased endocytotic or metabolic activi ty was demonstrated by the lack of non-phagocytotic cells. These experiment s call attention to the evolutionary role of selection in the later develop ing receptor-hormone relationship. (C) 2001 Elsevier Science Inc. All right s reserved.