Submitted to: Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: April 17, 1999
Publication Date: N/A
Technical Abstract: Retinoids have been shown to have a profound effect on cellular growth and differentiation. More specifically, retinoic acid compounds are immunoregulatory agents with demonstrated enhancement in proliferative action of both T and B lymphocyte populations. In the present study, various levels of 9-cis-retinoic acid, 13-cis-retinoic acid and all-trans-retinoic acid (RA) were evaluated in vitro for their ability to increase proliferation of 7TD1.B3 cells, an IL-6-dependent lymphoid cell line, to supplemental IL-6. Addition of RA compounds (2 to 20 ng/ml) with 1 or 2 IU/ml of rmuIL-6 significantly increased proliferative responses (62% and 46%, respectively) of 7TD1.B3 cells compared to cells with no added RA. To evaluate the RA-induced augmentation of cellular proliferation we measured expression of IL-6 receptors (IL-6r) on 7TD1.B3 cells by flow cytometry, ELISA and immunohistochemistry using an IL-6r antibody. A significant shift in cell populations stained with FITC-labeled anti-IL6r occurred after incubation of cells with 13-cis-RA for 24 hours prior to flow cytometric analysis. An increase in ELISA absorption values (A405nm) for soluble IL-6r and more intense cellular staining for IL-6r by immunohistochemical analysis of 7TD1.B3 cells after incubation with 13-cis-RA for various time periods was also noted. In summary, these data suggest that a potential immunomodulatory role of RA compounds may be an upregulation of IL-6r on lymphoid cell populations.