Melatonin provides signal 3 to unprimed CD4+ T cells but failed to stimulate LPS primed B cells

Abstract

SUMMARYGrowing evidence has supported the conclusion that melatonin, a pineal hormone, modulates the immune function. In our previous study, we evaluated in vivo the potential role of melatonin in the regulation of the antigen specific T and B cells. In the present study, we observe that melatonin downregulated the expression of the co-stimulatory molecule B7-1 but not B7-2 on macrophages. Further, melatonin encouraged the proliferation of anti-CD3 antibody activated CD4 1 T cells only in the presence of antigen-presenting cells and promoted the production of Th2-like cytokines. Furthermore, it failed to influence the activity of B cells in a T-independent manner. Melatonin suppressed the release of TNF-a by LPS or IFN-g activated macrophages but failed to inhibit nitric oxide (NO) release. Thus the study shows that melatonin can engineer the growth of unprimed CD4 1 T cells if both the signals are provided by antigen-presenting cells. However, it could not regulate the function of B cells.

The Protective Effects of Melatonin Against Oxidative Stress and Inflammation Induced by Acute Cadmium Exposure in Mice Testis

“…Melatonin has been demonstrated to be an effective anti-oxidant and free radical scavenger [17][18][19]. In addition, it has also been shown to have an anti-inflammatory effect and suppresses pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and IL-6 [20][21][22][23][24][25]. Melatonin administration ameliorates the proinflammatory state and oxidative stress in diabetic fatty rats [26].…”

Novel lectins from rhizomes of two Acorus species with mitogenic activity and inhibitory potential towards murine cancer cell lines

“…It has recently shown that the CD80 and CD86 expressed on B-cell lymphoma may promote or retard the growth by expressing anti-apoptotic and pro-apoptic molecules [26]. Further, melatonin, a pineal gland hormone can regulate the growth of T-cell lymphoma and normal T cell differentially [27].…”

Circadian Disorganization in Experimental Arthritis

“…Besides the release of proinflammatory Th-1 cytokines, such as IFN-Á and IL-2, administration of melatonin to antigen-primed mice increased the production of IL-10, indicating that melatonin also activates antiinflammatory Th-2-like immune responses [124,125]. It is not yet clear whether melatonin acts only on Th-1 cells or also on Th-2 cells.…”