thymopoietin-iii and Leukemia--Lymphoid

The capacity of ubiquitin (UB) and thymopoietin II (TP) related peptides (TP 5 and TP 13) to interfere with the specific binding of [3H]FTS on intact 1301 cells or on 1301 plasma membrane preparations was studied. All 3 peptides significantly inhibited the binding of [3H]FTS to its receptors on intact 1301 cells at concentrations 20 to 100 times higher than FTS itself. Conversely, none of the 3 peptides provided a significant inhibition of the specific [3H]FTS binding to plasma membrane preparations of 1301 cells compared to control peptides. These contrasted results suggest that TP-related peptides and, to a lesser degree, UB may share the same target cells with FTS and interfere with FTS effects on T cells, but this interaction probably does not involve direct high affinity binding to the FTS receptors.

Topics: Animals; Binding, Competitive; Cattle; Cell Line; Cell Membrane; Cell Transformation, Neoplastic; Chromosomal Proteins, Non-Histone; Enkephalin, Leucine; Glucagon; Humans; Leukemia, Lymphoid; Peptide Fragments; Receptors, Cell Surface; Receptors, Immunologic; Thymopentin; Thymopoietins; Thymus Hormones; Ubiquitins