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T cells and HIV-induced T cell syncytia exhibit the same motility cycle
A Sylwester1, D Shutt, D Wessels
1Department of Biological Sciences, University of Iowa, Iowa City 52242, USA.
Abstract:
Ameboid cells ranging in complexity from Dictyostelium amebas to human polymorphonuclear leukocytes (PMNs) translocate in a cyclical fashion. Using computer-assisted motion analysis, we have analyzed the motility of human lymphocytes of the immortal SupT1 cell line and of a peripheral blood mononuclear cell population highly enriched for CD4-positive cells (CD4-enriched PBMCs) on four substrates--plastic, dehydrated rat tail collagen, hydrated rat tail collagen, and bovine aortic endothelium. In addition, we have analyzed the motility on these substrates of syncytia induced by human immunodeficiency virus (HIV) in cultures of both cell types. It is demonstrated that both SupT1 cells and CD4-enriched PBMCs exhibit a motility cycle with a period of 1.6 min that is independent of substrate, independent of average cell velocity, and similar to the periods of translocating Dictyostelium amebas and PMNs. More surprisingly, it is demonstrated that HIV-induced SupT1 and PBMC syncytia with volumes 10 to 100 times those of single cells exhibit the same motility cycle as their single-cell progenitors. These observations support the generality of the motility cycle in animal cells and, for the first time, demonstrate that the cycle is independent of cell size.
Insights
Animal cells exhibit a cyclical movement pattern, with a consistent 1.6-minute cycle observed in human lymphocytes and even larger HIV-induced syncytia, regardless of substrate or cell size.
Area of Science:
- Cell Biology
- Biophysics
- Immunology
Background:
- Ameboid cell translocation is a fundamental biological process.
- Previous studies indicated cyclical movement in simpler organisms and certain human cells.
Purpose of the Study:
- To analyze the motility cycle of human lymphocytes and CD4-enriched PBMCs on various substrates.
- To investigate the motility of HIV-induced syncytia.
- To determine if cell size affects the motility cycle.
Main Methods:
- Computer-assisted motion analysis was employed.
- Motility was assessed on plastic, collagen (dehydrated and hydrated), and bovine aortic endothelium.
- Human lymphocytes (SupT1 cell line) and CD4-enriched PBMCs were studied, including HIV-induced syncytia.
Main Results:
- Both SupT1 cells and CD4-enriched PBMCs displayed a consistent motility cycle of 1.6 minutes.
- This cycle was independent of the substrate and average cell velocity.
- Surprisingly, larger HIV-induced syncytia (10-100 times cell volume) exhibited the same 1.6-minute motility cycle.
Conclusions:
- The 1.6-minute motility cycle is a general characteristic of animal cell translocation.
- Cell size does not influence the observed motility cycle, challenging previous assumptions.