Treatment with anti-CD86 costimulatory molecule prevents the autoimmune lesions in murine Sjögren's syndrome (SS) through up-regulated Th2 response

Abstract

Intraperitoneal administration with anti-CD86 (B7.2) MoAb into the murine model for primary SS in NFS/sld mutant mice resulted in dramatically inhibitory effects on the development of autoimmune lesions, while no significant effects were observed when the mice were administered with anti-CD80 (B7.1) MoAb. We found that spleen cells in the murine SS model treated with anti-CD86 MoAb showed a significant impairment of autoantigen-specific T cell proliferation. T cell activation markers (CD44high, CD45RBlow, Mel-14low) were significantly down-regulated in the spleen cells gated on CD4 in anti-CD86-treated mice. We detected a higher level of cytokine production of IL-4 from splenic T cells in anti-CD86-treated mice, but not of IL-2, and interferon-gamma (IFN-gamma), compared with those in the anti-CD80- and PBS-treated SS model. Moreover, serum autoantibody production against alpha-fodrin autoantigen was almost entirely suppressed in anti-CD86-treated mice. These data provide strong evidence that in autoimmune exocrinopathy resembling SS in NFS/sld mutant mice, the CD86 costimulatory molecule plays a crucial role in the initiation and subsequent progression of Th1-mediated autoimmunity in the salivary and lacrimal glands.

Fig. 1

Flow cytometric analysis of CD80 and CD86 expression on isolated mouse salivary gland cells and spleen cell suspensions from 3d-thymectomized (Tx) NFS/sld mice (control) gated on I-A^s. While no difference was observed between CD80⁺ (28%), and CD86⁺ (27%) cells in the isolated mouse salivary gland epithelial cells, a larger proportion of spleen cells was CD86⁺ (55%) than of cells expressing CD80 (10%). Three experiments in each group (8 weeks old) were performed.

Fig. 2

Preventive effect of i.p. injection of anti-CD86 MoAb. Anti-CD80 MoAb (100 μg) (n = 8), and anti-CD86 (n = 8) were injected intraperitoneally into 3d-thymectomized (Tx) NFS/sld mice once a week (treated with MoAb from 3–7 weeks). These groups were compared with controls treated with PBS alone (n = 7). Mice with treatment were examined histopathologically at 8 weeks. Mean grade of inflammatory lesions was expressed as described in Materials and Methods. *P < 0.01, Mann–Whitney U-test.

Fig. 3

Effect of in vivo treatment with anti-CD86 MoAb on proliferative T cell response to the recombinant α-fodrin autoantigen. A significant inhibitory effect on T cell blastogenesis to the recombinant α-fodrin autoantigen was observed in 3d-thymectomized (Tx) NFS/sld mice treated with anti-CD86 MoAb, but not in those treated with anti-CD80 (*P < 0.05, Student's t-test). No difference was observed in concanavalin A (Con A)-stimulated blastogenesis measured in spleen cells from each group of mice. Three experiments in each group of the same age were performed. Data are expressed as ct/min per culture ± s.d. in triplicate.

Fig. 4

Flow cytometric analysis of activation markers in spleen cells (a) and regional lymph node (LN) cells (b) from anti-CD86-treated and PBS-treated 3d-thymectomized (Tx) NFS/sld mice gated on CD4⁺. Down-regulation of activation markers (CD44^high, CD45RB^low, and Mel-14^low) was clearly observed in both splenic and LN CD4⁺ cells (more prominent in LN cells) from anti-CD86-treated mice, compared with PBS-treated mice. Five mice of the same age (8 weeks old) were analysed.

Fig. 5

Splenic T cell culture supernatants in 3d-thymectomized (Tx) NFS/sld mice treated with anti-CD86 MoAb contained a high level of IL-4, but a lower level of IL-2, and IFN-γ by ELISA (*P < 0.05, Student's t-test). Five mice from each group (8 weeks old) were analysed.