Date of Award:


Document Type:


Degree Name:

Master of Science (MS)



Committee Chair(s)

Reed P. Warren


Reed P. Warren


John Simmons


Dennis Odell


The purpose of this study was to identify the effects of the neurotransmitter, serotonin (SE), on the immune function of peripheral blood mononuclear cells (PBMC) of normal, healthy subjects. This was done as a preliminary investigation to studies on the association of SE with immune changes in autistic subjects.

The PBMC isolated from normal male subjects were treated with various concentrations of SE for 48 hrs. Their incubation in SE at a concentration of 10-3 M induced about a 35% decrease in DNA synthesis. However, incubation of the cells in lower concentrations (10-4 to 10-10) of SE produced no significant effect. The ability of natural killer (NK) cells to lyse K562 target cells was also examined after incubation with SE for 48 hrs. The NK activity was almost completely eliminated following incubation in 10-3M of SE, but the activity was not significantly decreased by exposure to lower concentrations of SE. The viability of PBMC was not altered following incubation with SE under identical conditions as those utilized in the NK assay.

Preliminary analysis using a fluorescence-activated cell sorter (FACS) of monoclonal antibodies directed against Tll (total T cell), T4 (helper T cell), T8 (suppressor and cytotoxic T cells), B-cell and NK cell markers indicated that the suppressive effect exerted by SE could be attributed to a decrease in the density of these markers or receptors on the cell surface. These findings provide additional evidence for a possible link between neurotransmitters, specifically SE, and immune function.



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