Retinoic acid-induced modulation of il-2 mrna production and il-2 receptor expression on t cells

Background: Retinoic acid (RA) has important immune-modulating effects on both T and B cell function. Our laboratory has shown that RA can enhance in vitro polyclonal B cell immunoglobulin (Ig) response. Investigating cytokines known to affect B cell differentiation, we have recently shown that IL-6 production is augmented by RA. In the present study we have examined the immune modulating effects of RA on IL-2 mRNA, another important cytokine for B cell immunoglobulin production, the expression of IL-2 receptors on T cells, and the RA nuclear receptors. Methods: Purified T cells were obtained from adenoidal tissues, and incubated with RA (10⁷ M) or DMSO solvent/media control for 0, 6 to 8, and 24 h. Total mRNA was extracted from T cells, and using RT-PCR, changes in the production of IL-2 and RA receptors (RAR)αβγ mRNA were determined. The effects of RA on IL-2-α receptor expression was determined by flow cytometry on T cells. Conclusion: These studies suggest that RA can augment IL-2 mRNA production by T cells with a possible paracrine effect on IL-2R-α expression. These changes appear to be mediated by RAR-α. Thus, IL-2 may be another important cytokine modulated by RA in the immune response.