Phorbol 12,13-dibutyrate (P(Bu)2)-treated human blood mononuclear cells bind to each other.
Treatment of human blood mononuclear cells with nanomolar concentrations of phorbol 12,13-dibutyrate (P(Bu)2) induced their aggregation. The phenomenon was seen within a few minutes and reached its maximum manifestation after 20 min. At this time, 20-30% of unfractionated and nylon wool-passed mononuclear leukocytes were in the aggregates. The influence of pretreatment with 2-deoxyglucose, NaN3, EDTA, cyclohexamide, or incubation at 4 degrees C on the phenomenon indicated that it is energy and temperature dependent, requires the presence of extracellular divalent cations, and is independent of protein synthesis. Nonaggregating 2-deoxyglucose-and NaN3-pretreated cells could still bind [3H]P(Bu)2 which rules out the possibility that the phorbol ester molecule acts as a bridge between the aggregated cells. Seventeen percent of the P(Bu)2-treated T-cell population bound untreated autologous and allogeneic cells. The binding property has a certain species specificity because only 4% of the cells interacted with mouse lymphocytes. At the ultrastructural level, the intercellular binding showed broad areas of surface contact (both between lymphocytes and lymphocyte-monocyte) and "trapping" by surface processes was not seen. Aggregated cells did not show cytopathogenic changes.
D000818:Animals; D002449:Cell Aggregation / Q000187:drug effects; D002450:Cell Communication / Q000187:drug effects*; D003513:Cycloheximide / Q000494:pharmacology; D003847:Deoxyglucose / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004734:Energy Metabolism / Q000187:drug effects; D006801:Humans; D007962:Leukocytes / Q000378:metabolism / Q000502:physiology*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000502:physiology / Q000648:ultrastructure; D051379:Mice; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000494:pharmacology*; D010704:Phorbols / Q000494:pharmacology*
D010703:Phorbol Esters; D010704:Phorbols; D015240:Phorbol 12,13-Dibutyrate; D003513:Cycloheximide; D003847:Deoxyglucose; D004492:Edetic Acid