1Gamal El-Saeid Eid and 2Fahad J Al-Shammary
1Microbiology and Immunology Unit, 2Clinical Biochemistry Unit, Department of Clinical Laboratory Sciences, College of Applied Medical Science, King Saud University, Riyadh.
Mononuclear immune cells were
separated from whole peripheral blood samples obtained from 75 male and female
volunteers of different age groups. The cells were in vitro
stimulated with PHA-mitogen at different concentrations (0, 2.5, 5.0 and 10 mg/ml). The
effect of different concentrations of melatonin (0, 10-7, 10-6,
10-4 and 10-3 M) on the PHA- stimulated cells was studied
through ELISA measurements of IL-2 and IFN-g production. The results indicated that
the effect of melatonin on PHA-stimulated cells is dose dependent, with a
concentration of melatonin of 10-7 to 10-6 M to induce
the highest IL-2 and IFN-g production levels from both PHA-treated and non-treated cells.
Furthermore, the activity of melatonin was reduced by increasing its dose, where
the highest concentration of melatonin (10-3 M) induced significant
reduction of IL-2 and IFN-g production levels from cells of all sex and age groups. The
highest IL-2 production levels were detected at 10-7 M concentration
of melatonin, especially with cells isolated from young males and young
females. In contrast, the highest production levels of IFN-g were detected
with cells isolated form old males and old females when compared with young
groups. The results revealed that melatonin effect could be age-related and
support the suggestion that melatonin modulate the physiological activities
through Th-1 cells, the producers of the cytokines IL-2 and IFN-g.