Takanori Yasukochi

Therapeutic effects of antibodies to tumor necrosis factor-α, interleukin-6 and cytotoxic T-lymphocyte antigen 4 immunoglobulin in mice with glucose-6-phosphate isomerase induced arthritis

IntroductionImmunization with glucose-6-phosphate isomerase (GPI) induces severe arthritis in DBA/1 mice. The present study was designed to identify the cytokines and co-stimulatory molecules involved in the development of GPI-induced arthritis.MethodsArthritis was induced in DBA/1 mice with 300 μg human recombinant GPI. CD4+ T cells and antigen-presenting cells from splenocytes of arthritic mice were cultured in the presence of GPI. Tumor necrosis factor (TNF)-α, IFN-γ, IL-2, IL-4, IL-5, IL-6, IL-10, and IL-12 levels were assessed using cytometric bead array. Monoclonal antibodies to TNF-α, IFN-γ, IL-12, CD40L, inducible co-stimulator (ICOS), and cytotoxic T-lymphocyte antigen 4 immunoglobulin (CTLA-4Ig) were used to block TNF-α and IFN-γ production, examine clinical index in mice with GPI-induced arthritis, and determine anti-GPI antibody production.ResultsLarge amounts of TNF-α and IFN-γ and small amounts of IL-2 and IL-6 were produced by splenocytes from mice with GPI-induced arthritis. Anti-TNF-α mAbs and CTLA-4Ig suppressed TNF-α production, whereas anti-IFN-γ mAbs, anti-IL-12 mAbs, and CTLA-4 Ig inhibited IFN-γ production. A single injection of anti-TNF-α and anti-IL-6 mAbs and two injections of CTLA-4Ig reduced the severity of arthritis in mice, whereas injections of anti-IFN-γ and anti-IL-12 mAbs tended to exacerbate arthritis. Therapeutic efficacy tended to correlate with reduction in anti-GPI antibodies.ConclusionTNF-α and IL-6 play an important role in GPI-induced arthritis, whereas IFN-γ appears to function as a regulator of arthritis. Because the therapeutic effects of the tested molecules used in this study are similar to those in patients with rheumatoid arthritis, GPI-induced arthritis appears to be a suitable tool with which to examine the effect of various therapies on rheumatoid arthritis.

Use of laser microdissection in the analysis of renal-infiltrating T cells in MRL/lpr mice

To clarify the role of T cells in the kidneys of MRL/MpJ-lpr (MRL/lpr) mice, cytokine mRNA expression was analyzed, and tissue localization of T cells was examined by immunohistochemistry. Cells infiltrating the glomeruli, glomerular circumference, and perivascular areas in ten female MRL/lpr mice were captured by laser microdissection (LMD). Nested reverse transcription polymerase chain reaction (RT-PCR) of samples was performed with primers specific for β-actin, T-cell receptor β chain (TCR-Cβ), Thy-1, B220, CD4, CD8, interleukin (IL)-2, IL-4, IL-10, IL-13, IL-17, and interferon (IFN)-γ. Frozen sections of lesions were also stained immunohistochemically. B220, MAC-1, Thy-1, CD4, and CD8 staining was observed in glomeruli and perivascular areas, especially in glomerular circumference areas. T cells infiltrating the glomeruli, glomerular circumference areas, and perivascular areas produce INF-γ, IL-13, and IL-17 predominately. IL-10 positivity was identified in 60% of perivascular T cells but not in a substantial number of glomerular or periglomerular T cells. The results of our study suggest that the pathogenesis of renal lesions in MRL/lpr mice is complex and not due simply to the Th1 and Th2 balance. These findings also support the concept of different molecular mechanisms for glomerulonephritis and vasculitis in these mice.

Characterisation of Th1/Th2 type, glucose-6-phosphate isomerase reactive T cells in the generation of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disorder characterised by an unknown inflammatory process in multiple joints. The K/BxN T cell receptor transgenic mouse model is a striking model of inflammatory arthritis characterised by arthritic manifestations similar to those of RA.1 Matsumoto et al reported that arthritis could be provoked by linked T and B cell recognition of a ubiquitously expressed self antigen glucose-6-phosphate isomerase (GPI).2 Recently, immunisation with recombinant human GPI was reported to induce T cell dependent arthritis in DBA/1 mice,3 supporting the notion that GPI reactive T cells have a crucial role in the induction of arthritis. In our previous study we reported the presence of high titres of anti-GPI antibodies (Abs) in some patients with RA, although a few control subjects were also positive.4 To examine the role of GPI-specific T cells in …