Investigation of the role of CD70 in the development of experimental autoimmune uveitis in mice

Abstract

Purpose: The interaction between the TNF receptor family member CD27 on T cells and its ligand CD70 on antigen-presenting cells provides a costimulatory signal for T-cell activation. Blockade of CD70/CD27 is known to suppress Th1- and Th2-mediated diseases in several animal models. However, the role of CD70/CD27 interaction in autoimmune uveitis is unknown. Therefore, we investigated the effect of anti-CD70 antibody (Ab) on experimental autoimmune uveitis (EAU).

Methods: Female C57BL/6 mice were used. EAU was induced by active immunization with interphotoreceptor retinoid binding protein peptide (IRBP-p) 1-20 (day 0). Anti-CD70 monoclonal Ab (FR70) or control IgG was administrated intraperitoneally (300 µg/mouse/day) every two or three days from day -1 to day 7 (induction phase) or from day 8 to day 19 (effector phase). On day 20 after immunization, severity of EAU was assessed clinically and histopathologically. Activation of draining lymph node (LN) cells upon restimulation with IRBP-p in vitro was assessed by measuring proliferative response and production of cytokines (IFN-γ, TNF-α, IL-2, IL-5, IL-6, IL-10, and IL-17) in supernatant. Proportions of CD4⁺CD44^high, CD4⁺CD62L^high and CD4⁺CD25⁺Foxp3⁺ T cells were measured using a flow cytometer. In vitro effect of anti-CD70 Ab was assessed by measuring the proliferative response of LN cells isolated from EAU-induced mice cultured in the presence of IRBP-p with or without anti-CD70 Ab.

Results: Anti-CD70 Ab treatment from the induction phase of EAU apparently accelerated ocular inflammation, but not significantly (p=0.2). LN cells from anti-CD70 Ab-treated mice showed marked increases in proliferative response (p<0.01) and TNF-α and IFN-γ production upon restimulation with IRBP-p. Proportions of CD4⁺CD44^high, CD4⁺CD62L^high and CD4⁺CD25⁺Foxp3⁺ T cells were not different between two groups. In effector phase treatment, anti-CD70 Ab did not change severity of ocular inflammation (p=0.46) or LN cell activation. In vitro treatment with anti-CD70 Ab did not suppress the proliferative response of IRBP-p-reactivated LN cells from EAU-induced mice.

Conclusions: Anti-CD 70 Ab did not suppress EAU, but rather exacerbated EAU in induction phase treatment by increasing TNF-α and IFN-γ production from LN cells. Disease-specific inflammatory mechanism or different immunization protocol in different disease models may cause the diverse effects of anti-CD70 Ab.

Keywords: 746 uveitis-clinical/animal model • 432 autoimmune disease