Molecular basis for the immunosuppressive action of stearic acid on T cells.

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

T. M. Buttke (Creator)

P. W. Tebbey (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Studies were performed to determine the mechanism by which stearic acid (18: 0) selectively inhibits T-dependent immune responses in vitro. Incubation of mitogen-activated B and T cells with 18:0 resulted in dissimilar patterns of incorporation of the saturated fatty acid into their membranes. High-performance liquid chromatography (HPLC) analyses of T cells showed an accumulation of desaturated 18:0-containing phosphatidylcholine (PC) that replaced normal cellular PC. Less significant quantities of the same PC species were seen to accumulate in B-cell membranes; rather they increased their proportion of oleic acid (18: 1)-containing PC. The different lipid compositions of the lymphocyte cell membranes after exposure to 18:0 were correlated with their plasma membrane potentials. In T cells the accumulation ofdesaturated 18: 0-containing PC coincided with a rapid (within 8 hr) collapse ofmembrane integrity as determined by flow cytometry. The collapse of membrane integrity was found to be time and dose dependent. No such depolarization was observed in B cells which by virtue of their desaturating ability were able to avoid incorporating large amounts of desaturated 18: 0-containing phospholipids into their membranes. It is proposed that a lack of stearoyl-CoA desaturase in T cells precludes them from desaturating exogenously derived 18:0 thus leading to increased proportions of 18:0-containing desaturated PC in their cell membranes. The increased abundance of this PC species may enhance membrane rigidity to an extent that plasma membrane integrity is significantly impaired leading to a loss ofmembrane potential and ultimately cell function and viability. Originally published Immunology Vol. 70 No. 3 July 1990

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Immunology. 70:3(July 1990) p. 379-386.

Language: English

Date: 2011

Keywords

stearic acid, T-dependent immune response, response mechanisms

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